October 2014 ijspt

IJSPT

INTERNATIONAL JOURNAL OF SPORTS PHYSICAL THERAPY

VOLUME NINE issue Five october 2014

IJSPT

INTERNATIONAL JOURNAL OF SPORTS PHYSICAL THERAPY

Editor in Chief Michael L. Voight, PT, DHSc, OCS, SCS, ATC, CSCS Belmont University Nashville, Tennessee – USA

Associate Editors, Thematic Issues: Robert Manske, PT, DPT, Med, SCS, ATC, CSCS Wichita State University Wichita, Kansas – USA

Senior Associate Editor Barbara Hoogenboom, PT, EdD, SCS, ATC Grand Valley State University Grand Rapids, Michigan - USA

Associate Editors: Mario Bizzini, PT, MSc Schulthess Clinic Zürich – Switzerland

Manuscript Coordinator Ashley Campbell

Henning Langberg, PT, PhD, MSc Institute of Sports Medicine Copenhagen – Denmark

Managing Editor Mary Wilkinson

Editorial Board: Scott Anderson, PT, Dip Sport PT Northgate Physical Therapy Regina, Saskatchewan – Canada

John A. Guido, Jr., PT, MHS, SCS, ATC, CSCS Ochsner Health Systems New Orleans, Louisiana – USA

Lindsay Becker, PT, DPT, SCS, CSCS The Ohio State University Sportsmedicine Center Columbus, Ohio – USA

Elizabeth L. Harrison, PT, PhD, Dip Sport PT University of Saskatchewan Saskatoon, Saskatchewan – Canada

Barton Bishop, PT, DPT, SCS, CSCS Sport and Spine Rehab of Rockville Rockville, Maryland – USA

Walter L. Jenkins, PT, DHS, ATC East Carolina University Greenville, North Carolina - USA

Turner A. “TAB” Blackburn, Jr., MEd, PT, ATC Clemson Sports Medicine and Rehabilitation Manchester, Georgia – USA

Daniel S. Lorenz, PT, DPT, ATC, CSCS Providence Medical Center Kansas City, Kansas - USA

Robert J. Butler, PT, DPT, PhD Duke University Durham, NC – USA

Lorrie Maffey, PT, MPT, Dip Manip PT University of Calgary Calgary, Alberta – Canada

Rick Clark, PT, DScPT, CCCE Air Force Academy Colorado Springs, CO – USA

Terry Malone, PT, EdD, ATC, FAPTA University of Kentucky Lexington, Kentucky – USA

George J. Davies, PT, DPT, SCS, ATC, FAPTA Armstrong Atlantic State University Savannah, Georgia – USA

Peter J. McNair, PT, PhD Auckland University of Technology Auckland – New Zealand

Mark S. De Carlo, PT, DPT, MHA, SCS, ATC Accelerated Rehabilitation Indianapolis, Indiana – USA

Grethe Myklebust, PT, PhD Oslo Sport Trauma Research Center Norwegian School of Sports Sciences Oslo – Norway

Todd S. Ellenbecker, DPT, SCS, OCS Physiotherapy Associates Scottsdale Sports Clinic Scottsdale, Arizona – USA

EDITORIAL STAFF & BOARD

Phil Page, PT, PhD, ATC, CSCS The Hygenic Corporation Akron, Ohio – USA

Kevin Wilk, PT, DPT Champion Sports Medicine Birmingham, Alabama – USA

Mark Paterno, PT, PhD, MBA, SCS, ATC Cincinnati Children’s Hospital Medical Center Cincinnati, Ohio – USA

Erik Witvrouw, PT, PhD Ghent University Ghent – Belgium

Michael P. Reiman, PT, DPT, OCS, SCS, ATC, FAAOMPT, CSCS Duke University School of Medicine Durham, North Carolina – USA Mark F. Reinking, PT, PhD, SCS, ATC Saint Louis University St. Louis, Missouri – USA Jill Robertson, PT, MSc (PT), Dip Manip PT Beaverbank Orthopaedic and Sport Physiotherapy Halifax, Nova Scotia – Canada Kevin Robinson, PT, DSc, OCS Belmont University Nashville, Tennessee – USA Barbara Sanders, PT, PhD, SCS, FAPTA Texas State University-San Marcos San Marcos, Texas – USA Teresa L. Schuemann, PT, DPT, SCS, ATC, CSCS Colorado Physical Therapy Specialists Fort Collins, Colorado – USA Patrick Sells, DA, ES Belmont University Nashville, Tennessee – USA Laurie Stickler, MSPT, OCS Grand Valley State University Grand Rapids, Michigan – USA Steven R. Tippett, PT, PhD, SCS, ATC Bradley University Peoria, Illinois – USA Timothy F. Tyler, PT, ATC NISMAT Lenox Hill Hospital New York, New York – USA Timothy Uhl, PT, PhD, ATC University of Kentucky Lexington, Kentucky – USA Mark D. Weber, PT, PhD, SCS, ATC University of Mississippi Medical Center Jackson, Mississippi – USA

IJSPT

international JOURNAL OF SPORTS PHYSICAL THERAPY

I N T E R N AT I O N A L J O U R N A L OF SPORTS PHYSICAL THERAPY

SPORTS PHYSICAL THERAPY SECTION

Editorial Staff

Executive Committee

Michael L. Voight, PT, DHSc, OCS, SCS, ATC Editor-in-Chief

Tim Tyler, PT, MS, ATC

Barbara Hoogenboom, PT, EdD, SCS, ATC Grand Valley State University Grand Rapids, Michigan - USA Senior Associate Editor

Robert Manske, PT, DPT, Med, SCS, ATC, CSCS Vice President

Robert Manske, PT, DPT, Med, SCS, ATC, CSCS Wichita State University Wichita, Kansas – USA Associate Editor, Thematic Issues Associate Editors Mario Bizzini, PT, MSc Schulthess Clinic Zürich – Switzerland Henning Langberg, PT, PhD, MSc Institute of Sports Medicine Copenhagen – Denmark Ashley Campbell Manuscript Coordinator Mary Wilkinson Managing Editor

Advertising Sales The International Journal of Sports Physical Therapy accepts advertising on its website, www.ijspt.org.

President

Teresa L. Schuemann, PT, DPT, SCS, ATC, CSCS Secretary Bryan Heiderscheit, PT, PhD Treasurer Stacey J. Pagorek, PT, DPT, SCS, ATC Representative-At-Large

Administration Mark S. De Carlo, PT, DPT, MHA, SCS, ATC Executive Director Tammy Jackson Executive Assistant Mary Wilkinson Director of Marketing Webmaster Managing Editor, Publications

Contact Information 9002 N. Meridian Street, Suite 112A Indianapolis, Indiana 46260 877.732.5009 Toll Free • 317.829.5790 Voice 317.829.5791 Fax www.spts.org

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You may also email Mary Wilkinson, Marketing Director, at mwilkinson@spts.org or contact by phone at 317.501.0805.

I N T E R N AT I O N A L J O U R N A L OF SPORTS PHYSICAL THERAPY is a publication of the Sports Physical Therapy Section of the American Physical Therapy Association.

IJSPT is also an official journal of the International Federation of Sports Physical Therapy (IFSPT).

IJSPT is a bimonthly publication, with release dates in February, April, June, August, October and December.

ISSN 2159-2896

TABLE OF CONTENTS VOLUME 9, NUMBER 5

Page Number

Article Title

Original Research 564

Hip Muscle Strength and Endurance in Females with Patellofemoral Pain: A Systematic Review with Meta-analysis.

Authors: Van Cant J, Pineux C, Pitance L, Feipel V

583

Injury Risk is Altered by Previous Injury: A Systematic Review of the Literature and Presentation of Causative Neuromuscular Factors.

Authors: Fulton J, Drvol C, Kelly M, Wright K, Zanis M, Zebrosky B, Butler R

596

Normative Data for Hop Tests in High School and Collegiate Basketball and Soccer Players.

Authors: Myers BA, Jenkins WJ, Killian C, Rundquist P

604

Relationships Between Core Endurance, Hip Strength, and Balance in Collegiate Female Athletes.

Authors: Ambegaonkar JP, Mettinger L, Caswell SV, Burtt A, Cortes N

617

Sidestep and Crossover Lower Limb Kinematics During a Prolonged Sport-Like Agility Test Authors: Potter D, Reidinger K, Szymialowicz R, Martin T, Dione D, Feinn R, Wallace D, Garbalosa J

628

Comparison of Isometric Ankle Strength Between Females With and Without Patellofemoral Pain Syndrome Authors: Carvalho-e-Silva A, Magalhaes E, Bryk F, Fukuda T

635

The Effect of Exercise and Time on the Height and Width of the Medial Longitudinal Arch Following the Modified Reverse-6 and the Modified Augmented Low-Dye Taping Procedures Authors: Cornwall M, McPoil TG, Fair A

644

Validation of a New Method for Assessing Scapular Anterior-Posterior Tilt Authors: Scibek JS, Carcia CR

657

The Relationship Between Glenohumeral Joint Range of Motion and The Functional Movement Screen Shoulder Mobility Test Authors: Sprague PA, Mokha M, Gatens D, Rodriquez R

665

Kinesiology Taping and the World Wide Web: A Quality and Content Analysis of InternetBased Information Authors: Beutel BG, Cardone DA

674

Ohio Physical Therapists’ Accuracy in Identifying Abnormalities on Diagnostic Images with and without a Clinical Vignette Authors: Morris AT, Cook C, Hassen A

Case Report 691

Utilization of Autoregulatory Progressive Resistance Exercise in Transitional Rehabilitation Periodization of a High School Football-Player following Anterior Cruciate Ligament Reconstruction: A Case Report Author: Horschig A, Neff T, Serrano A

699

Treatment of Non-specific Thoracic Spine Pain with Trigger Point Dry Needling and Intramuscular Electrical Stimulation: A Case Series Authors: Rock JM, Rainey CE

Clinical Commentary 712

Return to Swimming Protocol for Competitive Swimmers: A Post-Operative Case Study and Fundamentals Authors: Spigelman T, Sciascia A, Uhl T

726

Beyond Statistical Significance: Clinical Interpretation of Rehabilitation Research Literature.

Author: Page P

IJSPT

SYSTEMATIC REVIEW

HIP MUSCLE STRENGTH AND ENDURANCE IN FEMALES WITH PATELLOFEMORAL PAIN: A SYSTEMATIC REVIEW WITH META-ANALYSIS Joachim Van Cant, PT1,2 Catherine Pineux, PT3 Laurent Pitance, PT, PhD3 Véronique Feipel, PT, PhD2

ABSTRACT Purpose/Background: Patellofemoral pain (PFP) is a common knee conditions experienced by adolescents and young adults, seen particularly in women. Clinicians and researchers need to understand how proximal, local, or distal factors may influence the development of PFP and affect individuals once they have developed PFP. Proximal factors are the focus of recent studies and the purpose of this systematic review was to determine if females with PFP have hip muscle strength or endurance deficits when compared to their unaffected leg and to comparison groups.

Methods: A systematic review was conducted to identify relevant studies in the databases PubMed, PEDro, ScienceDirect and EBSCOhost up to June 2013. Data including study design, participants demographic data, and assessments of hip muscle strength or endurance were extracted from individual trials. The mean differences of hip muscles strength or endurance between females with PFP and healthy controls or unaffected side were extracted or calculated from individual trials and, when possible, a meta-analysis was performed.

Results: Ten cross-sectional studies were included in this review. Concerning isometric strength, pooled data reported deficit in hip abduction, extension, external rotation and flexion but no deficit in adduction and internal rotation when compared with healthy controls. When compared with the unaffected side, deficit in hip abduction was reported in two studies and deficit in extension and external rotation in one study. Studies with isokinetic strength evaluation reported deficit in abduction but contradictory results for extensors and rotators in females with PFPS. Finally, one study reported hip endurance deficit in extension and one found no significant differences in hip endurance compared to control subjects.

Conclusion: The results of this systematic review confirm that females with PFPS have deficit in hip muscle strength compared with healthy controls and the unaffected side but are contradictory concerning endurance.

Key Words: Endurance, Female, Hip, patellofemoral pain, strength Level Of Evidence: 2a

1

Department of Physical Therapy, Institut Parnasse-ISEI, Brussels, Belgium 2 Laboratory of Functional Anatomy, Faculty of Motor Sciences, Université Libre de Bruxelles, Brussels, Belgium.

3 Institute of Neuroscience, Faculty of Motor Sciences, Université Catholique de Louvain, Brussels, Belgium.

The authors certify that they have no affiliations with or financial involvement in any organization or entity with a direct financial interest in the subject matter or materials discussed in the article.

CORRESPONDING AUTHOR Joachim Van Cant (PT, PhD student), Department of Physical therapy, Institut Parnasse-ISEI, Avenue Mounier 85, 1200 Brussel, Belgium.

E-mail: jvancant@parnasse-isei.vinci.be

The International Journal of Sports Physical Therapy | Volume 9, Number 5 | October 2014 | Page 564

INTRODUCTION Patellofemoral pain (PFP) is the most common knee condition experienced by active adolescents and young adults.1 Boling et al2 reported that females are significantly more likely to develop PFP than males while Roush et al3 estimated a prevalence rate of 12-13% in females 18 to 35 years of age. Symptoms are characterized by anterior, retro or peripatellar pain during activities such as squatting, kneeling, prolonged sitting, ascending or descending stairs, running, hopping, and jumping.4,5 Diagnosis of PFP is clinical in nature, and must exclude pain due to meniscal, cruciate or collateral ligament injuries, patellar tendinopathy, Osgood-Schlatter or SindingLarsen-Johansson syndrome, or other pathologic conditions.6 Researchers suggest that PFP is a multifactorial problem.7 Potential impairments that have been associated with PFP include increased quadriceps angle,8 hypermobile patella,8 altered lower limb kinematics,9 muscle dysfunction,10,11,12 and decreased lower limb flexibility.13,14 During the last decade, numerous researchers have investigated the connection between and supported the influence of the hip on PFP.9,10,11,12,15 Powers et al16 reported that impaired muscular control of the hip can increase hip adduction or internal rotation and, therefore, increase the quadriceps angle (Q-angle) during dynamic movements. Huberti and al17 showed that a 10-degree increase in the Q-angle can increase patellofemoral contact pressures by 45% at 20° of flexion of the knee. Repetition of this excessive movement may contribute to development of PFP.18 Based on these studies, authors have hypothesized that deficit of hip muscular strength or endurance may increase femoral movement during functional tasks and contribute to the development of PFP.7,18 Additionally, Powers19 suggested that females are more predisposed to hip neuromuscular deficits than males.19 Prins et al20 performed a systematic review of five studies7,18,21,8,22 assessing hip strength in females with PFP. Because data were insufficiently reported and methodologies varied, the authors chose not to implement a meta-analysis. The authors reported hip muscle weakness in participants with PFP compared with healthy controls. All included

studies tested maximum isometric strength assessed with hand held dynamometry. Additionally, specific research questions for their review were targeted on hip strength and not endurance.

Since the work presented by Prins et al,20 several studies have been performed that evaluated hip muscle function in females with PFP, including strength and endurance evaluation using varied assessment techniques (isometric, isotonic, isokinetic).

Therefore, the purposes of this systematic review were: • To determine if females with PFP have isometric and isokinetic hip muscle strength deficits when compared to their unaffected leg and to comparison groups. • To determine if females with PFP have hip muscle endurance deficits when compared to their unaffected leg and to comparison groups.

A systematic review was conducted and when metaanalysis was possible, data from individual studies were pooled and analyzed.

METHODS Search strategy A systematic search strategy was utilized in order to identify relevant studies in the databases PubMed, PEDro, ScienceDirect and EBSCOhost up to June 2013. The following key words were combined: patellofemoral pain syndrome, anterior knee pain, hip, muscle strength, muscle endurance, female. The search was applied without restrictions on language or year of publication. Study types searched excluded systematic reviews, meta-analyses, case series, and case reports. Furthermore, this strategy was supplemented by hand searching the references of all articles selected for the review.

Study Selection Studies were selected using the following criteria: (1) studies had to assess hip muscle strength or endurance in females with PFP; (2) studies that included both males and females had to describe specific results for females; (3) studies had to include a healthy control group. Studies focusing on other knee pathologies were excluded.

The International Journal of Sports Physical Therapy | Volume 9, Number 5 | October 2014 | Page 565

The selection of studies was performed independently by two reviewers (JVC and CP) based on the title and the abstract. Articles not excluded by both reviewers were assessed in full-text and disagreement regarding inclusion was resolved by consensus.

Data Extraction and Synthesis The first author extracted data including study design (type, author, date), participants (number, age, activity level, PFP definitions) and assessment of hip muscle strength or endurance (nature of contraction, body position, type of fixation and instrument used, number of trials, dynamometer placement, measurement units). When possible, the mean differences (MDs) of hip muscles strength or endurance between females with PFP and healthy controls or unaffected side, were extracted or calculated from individual trials, with matching 95% confidence intervals (CIs). If data were missing, information was requested from the authors. Nature of contraction (isometric, isotonic or isokinetic) and type of instrument used were also determined and recorded for data extraction or calculation.

When meta-analysis was possible, data from individual studies were pooled with the software package Review Manager 5 (Nordic Cochrane Center, Copenhagen, Denmark) to determine a weighted mean difference (WMD) or a weighted standardized mean difference (WSMD) with a 95% CI.23 Two statistical methods were used to analyze statistical heterogeneity, the chi-square test for heterogeneity and the I² test. When the chi-square test is significant, statistical heterogeneity is present.24 The percentage of I² represents the percentage of total variation across studies due to heterogeneity and is interpreted as 25% indicating low heterogeneity, 50% medium heterogeneity, and 75% high heterogeneity.25 The meta-analysis was conducted using a randomeffects model. If heterogeneity between studies was medium or high or if data were not sufficient for a meta-analysis, a descriptive analysis was performed.

Methodological Quality Assessment The authors created a methodological quality assessment list with items from the Newcastle-Ottawa Scale, the Dutch Cochrane Centre website (http://

dcc. cochrane.org/dutch-cochrane-centre), the Cardiff University Systematic Review Network (http:/ www.cardiff.ac.uk/insrv/libraries/sure/sysnet), the Scottish Intercollegiate Guidelines Network (http:/ www.sign.ac.uk) and work by Higgins et al23 and Lankhorst et al26.

Table 1 lists the resulting 10 questions that were used for assessing the methodological quality of the studies. Two reviewers (JVC and CP) assessed the included studies independently. Disagreements between reviewers were resolved through a consensus procedure. Each item was rated as “positive”, “unclear” or “negative”. Because calculating a summary score is explicitly discouraged by Higgins et al,23 a total score was not calculated.

RESULTS Flow of Study Selection The database search identified 686 potentially relevant articles (Appendix A). After exclusion of 670 studies from titles and abstracts, 16 articles were retrieved for full-text review. On basis of the full-text review, the authors’ excluded five articles because subgroups for females or healthy control groups were not included. Souza and Powers27,28 and Bolgla et al7,29 each published two articles with some similar data.

Data were extracted from both of these articles, but only Souza and Powers27 and Bolgla et al7 were used for citations. One study was added to the review after screening of the reference sections of selected articles.30 Ultimately, 10 studies were included in the systematic review.7,18,21,22,27,30,31,32,33,34 Figure 1 describes the flow chart of the studies selection.

Characteristics of the Included Studies Evaluation of studies: Table 2 reports methodological quality assessment list. Only two studies reported blinded application of evaluation18,32 and five used a functional assessment scale reported as reliable, valid and responsive in population with PFP.22,30,31,32,34 Moreover, studies often insufficiently described the place of recruitment, the activity level of participants, and experience and profession of the clinical investigator.

Participants: In total, 374 females were included in the studies. The number of participants ranged from

The International Journal of Sports Physical Therapy | Volume 9, Number 5 | October 2014 | Page 566

Table 1. Methodological Quality Assessment Questions & Scoring.

Methodological Quality Assessment Questions

Scored Positive if :

1. Did the study address an appropriate and clearly focused

Research question or hypothesis was that females

question?

with PFPS have decreased hip muscle force or endurance compared with healthy controls.

2. Was the study population clearly defined?

The place of recruitment, age and activity level were given.

3. Was patellofemoral pain syndrome clearly defined?

PFPS participants completed a reliable, valid scale responsive in this specific population. The intensity and history of symptoms was clearly documented.

4. Was the method of patellofemoral pain syndrome

The following information was described:

assessment reported?

-

Localization and activities associated with

symptoms of females with PFPS -

Exclusion criteria

-

Experience and profession of the clinical

investigator 5. Were the females with PFPS representative of the target

The participants were females, actives, between 18

population?

and 35 years of age.

6. How comparable are the females with PFPS and healthy

Age and activity level are comparable between both

controls with respect to potential confounding factors?

groups. Strength or endurance were normalized to body weight.

7. Were the same exclusion criteria used for both females

The exclusion criteria were described and similar

with PFPS and healthy controls?

for both groups.

8. Was the method of hip muscle strength or endurance

Body position, type of fixation and instrument used,

assessment reported?

numbers of trials, order of testing sequences, verbal encouragement,

dynamometer

placement,

measurement units and warm-up were documented.

9. Was the same method of assessment for both females with

The same method of strength or endurance

PFPS and healthy controls?

assessment was used for both groups.

10. Were the assessors blinded to the different groups?

Blinded application of strength or endurance assessments was performed.

Abbreviations: PFPS=patellofemoral pain syndrome.

20 22,31 to 100.32 Only one study33 examined both males and females. In the others, all participants were female. The average age of participants ranged from 15.7 21 to 27 years.27Activity level was not speciďŹ ed in ďŹ ve studies.7,22,30,31,33 Table 3 provides the characteristics of participants.

Inclusion criteria for experimental groups: Participants complained of symptoms for a minimum of 4 to 12 weeks.7,21,30,31,32,33,34 Depending on the studies, participants had to report anterior, retro, or peripatel-

lar pain during at least two or three of the following provocative activities: squatting, kneeling, prolonged sitting, ascending or descending stairs, running, hopping, jumping, palpation or compression of medial or lateral patella facet, isometric quadriceps contraction.

Exclusion criteria for both groups: All studies excluded participants if they had previous knee surgery or signs of meniscal, cruciate or collateral ligament injuries, patellar dislocation, Osgood-Schlatter or Sinding-Larsen-Johansson syndrome, or other

The International Journal of Sports Physical Therapy | Volume 9, Number 5 | October 2014 | Page 567

Figure 1. Flow chart of study selection Table 2. Summary of Methodological Quality Assessment of Included Papers.

Quality assessment list Study Baldon et al31 Bolgla et al7 Cichanowski et al18 Ireland et al21 Magalhaes et al32 McMoreland et al30 Nakagawa et al33 Robinson and Nee22 Souza and Powers27 Willson and Davis34

1 + + + + + + + + + +

2 + + + + -

3 + + + + +

pathologic conditions. Cichanowski et al18 and Robinson and Nee22 excluded participants with bilateral PFP from their experimental groups,. Additionally, in one study, females over 45 were excluded.27 Table 4 describes the methods of evaluation of strength and endurance for included studies.

Hip muscles strength and endurance Isometric muscle strength: Maximum isometric strength was tested in eight studies. 7,18,21,22,27,30,32,34 In all studies hip abductors and external rotators

4 + + + + + + + +

5 ? + + + ? ? +

6 + + + + + + ? + +

7 + + + + + + + + +

8 + + + + + + + + + +

9 + + + + + + + + + +

10 + + -

were evaluated. Four authors investigated hip extensors,8,30,38,40 and three measured internal rotators.8,30,31 Hip flexors and adductors were evaluated in two studies.8,30 The pooled data demonstrated significantly lower strength in females with PFP than in healthy controls for abduction (WSMD, -0.75; 95% CI: -1.09, -0.41),7,18,21,22,27,30,32 external rotation (WSMD, -0.88; 95% CI: -1.17, -0.60),7,18,21,22,27,30,32,3 flexion (WSMD, -0.70; 95% CI: -1.14, -0.26)18,32 and extension (WSMD, -0.90; 95% CI: -1.50, -0.30).18,32,22,27 The pooled data were not significantly lower in females with PFP for

The International Journal of Sports Physical Therapy | Volume 9, Number 5 | October 2014 | Page 568

The International Journal of Sports Physical Therapy | Volume 9, Number 5 | October 2014 | Page 569 Abd: side lying ER/IR: sitting

Isometric muscle strength Isometric muscle strength

Isometric muscle strength

Muscle endurance

Ireland et al21

McMoreland et al31

Muscle endurance Isometric muscle strength Strapping.

Not reported

Not reproted

Not reported

Manual

Strapping

Strapping

Strapping

Manual

Strapping

Manual

Strapping

Strapping

Stabilisation

Abd: femoral condyle ER: malleolus

Ext : thigh

Abd: malleolus ER: malleolus Ext: thigh Abd: femoral condyle ER malleolus Ext thigh Ext : thigh

Abd: femoral condyle ER: malleolus

Abd: femoral condyle ER/IR: malleolus

Abd/Add: femoral condyle ER/IR: malleolus Ext /Flex: thigh Abd: femoral condyle ER: malleolus Abd, IR: lateral malleolus Add, ER: medial malleolus Flex/Ext: thigh Abd: femoral condyle ER/IR: malleolus

Abd: femoral condyle ER: malleolus

Abd/Add: femoral condyle ER/IR: malleolus

Dynamometer position

Range of motion

Ext: 30° of flex to 10° of ext N/A

Ext: 30° of flex to 10° of ext

N/A

Abd: 0°to 30° of abd ER: 5° of IR to 20° of ER N/A

75% of full active range of motion

N/A

N/A

N/A

N/A

Abd/Add: 0° to 30° of abd ER: 0° to 30° of ER IR : 0° to 30° of IR N/A

Eccentric and concentric Isometric

Eccentric and concentric

Isometric

Isometric

Eccentric

Concentric

Isometric

Isometric

Isometric

Isometric

Isometric

Eccentric

Contractions

Modalities

25% of body weight, 2.5 s/repetition Average of 3 trials

Average of 10 repetitions at 10°/s

Average of 3 trials

Average of 3 trials

Average of 5 repetitions at 30°/s

30 maximal repetitions at 30°/s

Average of 3 trials

Average of 2 trials

Best of 3 trials

Best of 2 trials

Average of 3 trials

Average of 5 repetitions at 30°/s

Abbreviations. Abd=abduction; add=adduction, ER=external rotation; IR=internal rotation; flex=flexion; ext=extension; ant=anterior; post=posterior.

Abd: side lying ER: prone

Ext.: prone knee flexed

Isometric muscle strength

Souza and Powers40

Willson and Davis46

Abd: side lying ER: sitting Ext.: prone knee flexed Abd : side lying Ext.: prone knee flexed ER: sitting Ext.: prone knee flexed

Isometric muscle strength

Robinson and Nee38

Isokinetic muscle strength

Abd: side lying ER: sitting

Isokinetic muscle strength

Nakagawa et al33

Magalhaes et al30

Abd/Add: side lying ER/IR/Flex: sitting Ext.: prone Abd: side lying ER: sitting Abd/Add: side lying ER/IR/Flex: sitting Ext.: prone knee extended Abd: side lying ER/IR: sitting

Isometric muscle strength

Cichanowski et al8

Abd: side lying ER: sitting

Isometric muscle strength

Bolgla et al3

Body position Abd /Add: side lying ER/IR: sitting

Isokinetic muscle strength

Baldon et al2

Evaluation

Table 4. Methods of strength and endurance evaluations.

Table 3. Characteristics of Participants.

Study

Participants PFPS

Baldon et al

31

Bolgla et al7 Cichanowski et al18

Ireland et al21

Magalhaes et al32

McMoreland et al30 Nakagawa et al33

Robinson and Nee22 Souza and Powers27 Willson and Davis34

Activity level Control

n= 10 Age (y) : 22.9 (SD : 5.2) n= 18 Age (y): 24.5 (SD : 3.2) n= 13 Age (y): 19.3 (SD : 1,1) n= 15 Age (y): 15.7 (SD : 2.7)

n= 10 Age (y): 23.9 (SD : 2.3) n= 18 Age (y): 23.9 (SD : 2.8) n= 13 Age (y): 19.5 (SD : 1.3) n= 15 Age (y): 15.7 (SD : 2.7)

n= 21 Age (y): 24.1 (SD : 6.3)

n= 50 Age (y): 24.6 (SD : 6.4)

n= 12 Age (y): 23 (SD : not mentioned ) n= 20 Age (y): 22.3 (SD : 3.1) n= 10 Age (y): 21.0 (range 12-34) n= 19 Age (y): 27 (SD : 6) n= 20 Age (y): 23.3 (SD : 3.1)

n= 12 Age (y): 21 (SD : not mentioned ) n= 20 Age (y): 21.8 (SD : 2.6) n= 10 Age(y): 26.6 (range 16-35) n= 19 Age (y) : 26 (SD : 4) n= 20 Age (y): 23.7 (SD : 3,6)

Not mentioned

Not mentioned

Female athletes

All subjects reported routine participation in either recreational or organized sports Sedentary (did not perform sports activities any day of the week for at least the previous 6 months) Recreational sports > 30 minutes three times weekly Not mentioned

Not mentioned

Active females

Recreational sports that require running or jumping (5/10 on the Tegner activity scale)

Abbreviations: PFPS=patellofemoral pain syndrome; SD=standard deviation; y=years. strength of adduction (WSMD, -0.35; 95% CI: -0.78, 0.08) 18,32 and internal rotation (WSMD, -0.36; 95% CI: -0.74, 0.03).18,30,32 Additionally, Magalhaes et al32 compared the average of both sides in participants with bilateral PFP to healthy controls and reported significant differences in abduction, extension, and external rotation. Willson and Davis34 did not provide sufficient information to calculate MDs with matching 95% CIs, however, they reported a statistically significant decrease in abductor and external rotator strength in females with PFP. When compared with the unaffected side, the pooled data showed a significant decrease in strength in abduc-

tion (WMD, -3.21; 95% CI: -5.20, -1.21) 18,32 and extension (WMD, -1.12; 95% CI: -5.14, 2.90) 18,32 but no significant differences between both sides for adduction (WMD, 0.15; 95% CI: -2.27, 2.58), 18,32 external rotation (WMD, -1.13; 95% CI: -2.84, 0.58), 18,32 internal rotation ((WMD, -1.17; 95% CI: -2.97, 0.64) 18,32 and flexion (WMD, -1.83; 95% CI: -4.40, 0.73). 18,32 Because of missing data and insufficient information to calculate MD with matching 95% CI, the data from Robinson et al22 were not pooled but their study reported a decrease in abduction, external rotation, and extension when compared to the unaffected side. Figures 2-7 display forest plots of the differences in hip isometric strength between females with PFP and controls (A), and between both sides (B).

The International Journal of Sports Physical Therapy | Volume 9, Number 5 | October 2014 | Page 570

Figure 2. Forest plot of the difference in hip abductors isometric strength between females with PFPS and controls (A) and between both sides (B)..

Figure 3. Forest plot of the difference in hip adductors isometric strength between females with PFPS and controls (A) and between both sides (B).

Isokinetic muscle strength: Peak torque during isokinetic evaluation was tested in three studies.27,31,33 Due to high heterogeneity, data from these studies could not be pooled. Baldon et al2 found eccentric peak torques significantly decreased in females with PFP for abduction (MD, -34.48; 95% CI: -41.81, -27.15), adduction (MD, -26.48; 95% CI:

-37.69, -15.27), and internal rotation (MD, -9.21; 95% CI: -16.90, -1.52) when compared with healthy controls. Nakagawa et al33 compared females with PFP to a control group and reported significantly decreased eccentric peak torques in females with PFP for abduction (MD, -17.00; 95% CI: -25.70, -8.30) and external rotation (MD, -9.00; 95% CI: -13.04, -4.96). Souza and

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Figure 4. Forest plot of the difference in hip external rotators isometric strength between females with PFPS and controls (A) and between both sides (B).

Figure 5. Forest plot of the difference in hip internal rotators isometric strength between females with PFPS and controls (A) and between both sides (B).

Powers27 compared eccentric and concentric peak torques of the hip extensors between females with PFP and healthy controls and found concentric peak torques to be significantly lower in females with PFP (MD, -16.00; 95% CI: -30.28, -1.72) but no significant difference between groups for eccentric isokinetic strength measures (MD, -5.00; -24.52, 14.52).

Muscle endurance: Two studies assessed hip muscle endurance, using isokinetic dynamometer.27,30 Souza and Powers27 evaluated endurance of hip extensors.

Subjects were instructed to contract against 25% of body weight and to perform as many repetitions as possible throughout the desired arc of motion. Each repetition was performed in 2.5 seconds. When suc-

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Figure 6. Forest plot of the difference in hip exors isometric strength between females with PFPS and controls (A) and between both sides (B).

Figure 7. Forest plot of the difference in hip extensors isometric strength between females with PFPS and controls (A) and between both sides (B).

cessful repetition was not achieved (arc of motion or time allotted), the dynamometer power output would drop. A drop to <75% torque output was considered a failed repetition and the test was terminated after two successive failed repetitions. The authors reported significantly fewer repetitions performed in females with PFP than in healthy controls (MD, -15.30; 95% CI: -20.17, -10.43). McMoreland et al30 tested endur-

ance of hip abductors and rotators between females with PFP and healthy controls. Total work (joules) produced during 30 maximal concentric repetitions at 30°/s was used to quantify muscle endurance. Their results showed no significant between-group difference for total work during tests. Appendix B reports all outcomes and mean differences of hip muscle strength and endurance for the included studies.

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DISCUSSION The aim of this systematic review was to determine if females with PFP have hip muscle strength and endurance deficits when compared to their unaffected leg and to comparison groups (normals).

The results confirm that females with PFPS have strength deficits of several hip muscles in comparison with healthy controls and the unaffected side, but are contradictory concerning endurance.

Hip muscle endurance and PFP Prins et al20 suggested that deficit in hip muscle endurance may contribute to PFP and hypothesized that muscles of patients with PFP have greater deficits in endurance than strength. Only two studies investigated these questions. McMoreland et al30 and Souza and Powers27 evaluated muscle endurance of the hip in females with and without PFP. Souza and Powers27 observed that females with PFP performed 49% less hip extension repetitions when compared with healthy controls. The authors suggested that these results may explain why symptoms in subjects with PFP increase during prolonged activities.

These findings may also help to explain observations by Dierks et al35 who described increased hip adduction in subjects with PFPS during prolonged running, especially at the end of the run. McMoreland et al30 reported a moderate correlation between strength and endurance and suggested that clinicians should evaluate both measures separately, however, they found no significant differences in hip endurance compared to control subjects.30 A possible explanation for these contradictory results may be differences in level of pain in the study population as compared to the controls. Indeed, the study of McMoreland et al30 included females with mild patellofemoral pain while other studies included subjects ranging from mild to severe pain. The question concerning whether there is a lack of hip muscle endurance in patients with PFP remains unanswered.

Hip muscle strength and PFP With regard to isometric strength of the hip, the results of studies indicated that a deficit in hip abduction, extension, external rotation, and flexion but no deficits in adduction and internal rotation when compared with healthy controls. However, differences in the number of studies pooled to evaluate each muscle group were observed. Seven studies were pooled

for abduction and external rotation,7,18,21,22,27,30,32 four for extension, 18,22,27,31 three for internal rotation18,30,32 and only two studies for flexion and adduction.18,32 Israel and Richter24 reported that combination of a large number of studies increases the statistical power by reducing the interval confidence and, therefore, by increasing the precision of the estimated population mean difference effect size. The results of studies in which participants were evaluated with isokinetic dynamometry demonstrated strength deficits in abduction but contradictory results were found for peak torques of extensors and rotators. Therefore, more studies are necessary to determine whether concentric, eccentric, or isometric deficits in hip muscles strength are comparable in females with PFP and which deficits is most likely related to function. The isometric strength of the hip in the side with PFP versus the unaffected side was evaluated in three studies. 18,22,32 Data from two studies were pooled and showed a decrease significant in hip abductors compared with the unaffected side.18,32 Data from Robinson and Nee22 also demonstrated a decrease in isometric external rotation and extension strength when examined versus unaffected side.

Cause or consequence of PFP In a prospective cohort study, Boling et al36 longitudinally followed 1597 healthy participants and included isometric hip muscle strength evaluation in their baseline data collection, using hand held dynamometer. A total of 40 participants developed PFP during the follow-up period (maximum of 2.5 years of follow up) but initial hip muscle strength deficits were not significantly associated with occurrence of PFP. Finnoff et al37 evaluated baseline isometric hip strength of high school running athletes at the beginning of the running season, using hand held dynamometery. The objective of this prospective study was to determine if pre-injury hip abductors weakness was associated with the development of PFP when compared to non-injured groups. Results showed that stronger hip abductors and weaker hip external rotators were risk factors of PFP. In addition, in the injured group, hip abduction and external rotation strengths decreased in post-injury when compared with their pre-injury evaluation. To date, it is difficult to determine whether deficits in hip muscle strength are a predisposing factor or conse-

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quence of PFP. Furthermore, none of these prospective studies evaluated hip muscle endurance.

Hip muscle strength and motion patterns in PFP Researchers have shown that abnormal lower leg and thigh motions in the transverse and frontal planes during weight-bearing activities could affect or increase retropatellar stress when compared to non-weight bearing activities.16,38 Powers19 determined that subjects with hip weakness demonstrate increased hip adduction, hip internal rotation, and knee valgus when compared with controls. Dierks et al35 compared hip strength and lower extremity kinematics before and after a prolonged run in patients with PFP and controls. The authors reported hip abductor weakness and alteration in the lower extremity kinematics in the PFP group and concluded that weaker hip abductor muscles were associated with increased hip adduction during running.

Conversely, Bolgla et al7 reported that females with PFP and hip weakness did not demonstrate altered hip and knee kinematics and other authors have not shown association between hip muscle weakness and lower extremity kinematics during single-legged 40 cm drop landings in healthy groups.39 Additional investigations are needed to fully understand relationship between hip muscle strength and lower extremity kinematics during functional activities in subjects with PFP. Effects of interventions Researchers have recently investigated the effectiveness of hip strengthening for patients with PFP. Four studies, with variable protocols, reported a significant decrease of pain and amelioration of function following an exercise program targeting the hip muscles.40,41,42,43 Dolak et al40 investigated the benefits of a four weeks strengthening program of hip abductors and external rotators compared to quadriceps strengthening. Thirty-three females with PFP were randomly assigned to a hip strengthening program (hip group) or a quadriceps strengthening program (quadriceps group) for four weeks. After completing the fourth week of rehabilitation, participants from both groups performed similar program of functional weight-bearing exercises for four additional weeks.

The hip group reported less pain than the quadri-

ceps group at four weeks (respectively 43% and 3% on the visual analogic scale). After eight weeks, results were similar for both approaches and showed significant improvement of function and decrease of pain. The authors emphasized the use of isolated hip strengthening exercises in the early rehabilitation stages to in order to reduce pain more efficiently.

Moreover, exercises described in the study used simple equipment such as elastic bands and can be easily included in a home training program.

Limitations Because PFP is a diagnosis is based on a group of symptoms and not a specific test, inclusion criteria often differed between studies. The studies included patients with some variability in terms of localization and history of pain and type of provocative activities.

Moreover, only five studies used valid and reliable scales, responsive in this specific population, like the Kujula scale.22,30,31,32,34 The systematic use of the Kujula scale in studies on PFP could allow optimal comparability between participants. PFP is a multifactorial and complex condition and it is evident that the target population is often heterogeneous and could be separated in subgroups. Additionally, participant characteristics were variable or unclear.

Females included in the examined studies were sedentary,32athletes,27 reported recreational sports participation,21,34 or their activity level was not specified.7,22,31,32,33 Authors should systematically describe participants demographic data and, similarly, there is a need to provide recommendations for selection of patients with PFP to improve the quality and consistency of research on this syndrome.

Methods for assessing hip strength were variable.

Subject and dynamometer position, type of contractions, measurement device and stabilization of the pelvis and upper leg differed among studies. Good to high reliability of hip strength evaluation using hand held or isokinetic dynamometery measures has been reported in the literature,44,45,46 except for measures of the internal rotators, which showed moderate reliability.44 Lower reliability could explain why authors who studied the strength of the internal rotators in female patients with PFP reported no strength deficit. Krause et al45 examined the effect of different testing positions on testâ&#x20AC;&#x201C;retest reliability and showed that the relative reliability of

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hip abduction and adduction strength evaluation in the side lying position was higher when using a long lever compared with a short lever. Thorborg et al46 reported less measurement variation in supine than in the side lying position when testing abduction and adduction. These results can explain the lack of agreement between studies and confirm the utility of establishing a standard method for hip strength and endurance evaluations.

Finally, the results of studies need to be interpreted with caution because, in most studies, the primary evaluator was not blinded to subject’s condition and bias might have been introduced during evaluation.

CONCLUSION This systematic review provides strong statistically significant evidence that females with PFP have significant isometric strength deficits in hip abduction, extension, and external rotation when compared with healthy controls. Moderate evidence was obtained concerning isometric strength deficit in flexion because the data of only two studies were pooled. There was no evidence that females with PFP have strength deficits in adduction and internal rotation. Moderate statistical evidence was found for isokinetic deficits in abduction and conflicting evidence for a deficit in rotation and extension.

When compared with the uninjured limb, moderate evidence was found for a strength deficit in abduction, conflicting with evidence for deficiencies in extension and external rotation strength and no evidence for internal rotation, adduction and flexion strength deficiencies. Finally, conflicting evidence was found regarding whether a decrease in hip muscular endurance exists in patients with PFP. REFERENCES 1. Latt. L., Raiszadeh K., Fithian D. Patellofemoral Joint Injuries. In: Kibler W.B. (Ed.) Orthopaedic Knowledge Update: Sport Medicine. Rosemond: The American Academy of Orthopaedic Surgeons.2009:119-134.

2. Boling M, Padua D, Marshall S, et al. Gender differences in the incidence and prevalence of patellofemoral pain syndrome. Scand J Med Sci Sports. 2010;20:725-730.

3 Roush JR, Curtis Bay R. Prevalence of anterior knee pain in 18-35 year-old females. Int J Sports Phys Ther. 2012;7:396-401.

4. Thomeé R, Renström P, Karlsson J, et al.

Patellofemoral pain syndrome in young women. I. A clinical analysis of alignment, pain parameters, common symptoms and functional activity level.

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5. Thomeé R, Augustsson J, Karlsson J. Patellofemoral pain syndrome: a review of current issues. Sports Med. 1999;28:245-262.

6. Cook C, Hegedus E, Hawkins R, et al. Diagnostic accuracy and association to disability of clinical test findings associated with patellofemoral pain syndrome. Physiother Can. 2010;62:17-24.

7. Bolgla LA, Malone TR, Umberger BR, et al. Hip strength and hip and knee kinematics during stair descent in females with and without patellofemoral pain syndrome. J Orthop Sports Phys Ther. 2008;38:1218.

8. Piva SR, Goodnite EA, Childs JD. Strength around the hip and flexibility of soft tissues in individuals with and without patellofemoral pain syndrome. J Orthop Sports Phys Ther. 2005;35:793-801.

9. Aminaka N, Pietrosimone BG, Armstrong CW, et al.

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10. Brindle TJ, Mattacola C, McCrory J. Electromyographic changes in the gluteus medius during stair ascent and descent in subjects with anterior knee pain. Knee Surg Sports Traumatol Arthrosc. 2003;11:244-251 11. Cowan SM, Crossley KM, Bennell KL. Altered hip and trunk muscle function in individuals with patellofemoral pain. Br J Sports Med. 2009;43:584588.

12. Dierks TA, Manal KT, Hamill J, et al. Proximal and distal influences on hip and knee kinematics in runners with patellofemoral pain during a prolonged run. J Orthop Sports Phys Ther. 2008;38:448-456.

13. Utting M., Davies G., Newman J. Is anterior knee pain a predisposing factor to patellofemoral osteoarthrisis? The Knee.2005;12:362-365.

14. Witvrouw E, Lysens R, Bellemans J, et al. Intrinsic risk factors for the development of anterior knee pain in an athletic population. A two-year prospective study. Am J Sports Med. 2000;28:480-489.

15. Meira EP, Brumitt J. Influence of the hip on patients with patellofemoral pain syndrome: a systematic review. Sports Health. 2011;3:455-465.

16. Powers CM, Ward SR, Fredericson M, et al.

Patellofemoral kinematics during weight-bearing and non-weight-bearing knee extension in persons with lateral subluxation of the patella: a preliminary study. J Orthop Sports Phys Ther. 2003;33:677-685.

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17. Huberti HH, Hayes WC. Patellofemoral contact pressures. The influence of q-angle and tendofemoral contact. J Bone Joint Surg Am. 1984;66:715-724.

18. Cichanowski HR, Schmitt JS, Johnson RJ, et al. Hip strength in collegiate female athletes with patellofemoral pain. Med Sci Sports Exerc.

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19. Powers CM. The influence of abnormal hip mechanics on knee injury: a biomechanical perspective. J Orthop Sports Phys Ther. 2010;40:42-51.

patellofemoral pain. Isokinetics and Exercise Science.

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31. Baldon Rde M, Nakagawa TH, Muniz TB, et al.

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2009;44:490-496.

32. Magalhães E, Fukuda TY, Sacramento SN, et al. A comparison of hip strength between sedentary females with and without patellofemoral pain syndrome. J Orthop Sports Phys Ther. 2010;40:641-647.

20. Prins MR, van der Wurff P. Females with patellofemoral pain syndrome have weak hip muscles: a systematic review. Aust J Physiother.

2009;55:9-15.

33. Nakagawa TH, Serrão FV, Maciel CD, Powers CM. Hip and knee kinematics are associated with pain and self-reported functional status in males and females with patellofemoral pain. Int J Sports Med. 2013;34:997-1002.

21. Ireland ML, Willson JD, Ballantyne BT, et al. Hip strength in females with and without patellofemoral pain. J Orthop Sports Phys Ther. 2003;33:671-676.

34. Willson JD, Davis IS. Lower extremity strength and mechanics during jumping in women with patellofemoral pain. J Sport Rehabil. 2009;18:76-90.

22. Robinson RL, Nee RJ. Analysis of hip strength in females seeking physical therapy treatment for unilateral patellofemoral pain syndrome. J Orthop Sports Phys Ther. 2007;37:232-238.

35. Dierks TA, Manal KT, Hamill J, et al. Lower extremity kinematics in runners with patellofemoral pain during a prolonged run. Med Sci Sports Exerc.

2011;43:693-700.

23. Higgins JPT, Green S, eds. Cochrane Handbook for Systematic Reviews of Interventions. Version 5.0.2. Oxford, UK: The Cochrane Collaboration; 2009 24. Israel H, Richter RR. A guide to understanding meta-analysis. J Orthop Sports Phys Ther. 2011;41:496504.

36. Boling MC, Padua DA, Marshall SW, et al. A prospective investigation of biomechanical risk factors for patellofemoral pain syndrome: the Joint Undertaking to Monitor and Prevent ACL Injury (JUMP-ACL) cohort. Am J Sports Med. 2009;37:21082116.

25. Higgins JPT, Thompson SG, Deeks JJ, et al.

Measuring inconsistency in meta-analyses. BMJ. 2003;327:557-560.

37. Finnoff JT, Hall MM, Kyle K, Krause DA, et al. Hip strength and knee pain in high school runners: a prospective study. PM R. 2011;3:792-801.

26. Lankhorst NE, Bierma-Zeinstra SM, van Middelkoop M. Risk factors for patellofemoral pain syndrome: a systematic review. J Orthop Sports Phys Ther.

2012;42:81-94.

38. Li G, DeFrate LE, Zayontz S, et al. The effect of tibiofemoral joint kinematics on patellofemoral contact pressures under simulated muscle loads. J Orthop Res. 2004;22:801-806.

27. Souza RB, Powers CM. Predictors of hip internal rotation during running: an evaluation of hip strength and femoral structure in women with and without patellofemoral pain. Am J Sports Med. 2009;37:579-587.

39. Lawrence RK 3rd, Kernozek TW, Miller EJ, et al.

Influences of hip external rotation strength on knee mechanics during single-leg drop landings in females. Clin Biomech (Bristol,Avon).2008;23:806-13..

28. Souza RB, Powers CM. Differences in hip kinematics, muscle strength, and muscle activation between subjects with and without patellofemoral pain. J Orthop Sports Phys Ther. 2009;39:12-19.

29. Bolgla LA, Malone TR, Umberger BR, Uhl TL. Comparison of hip and knee strength and neuromuscular activity in subjects with and without patellofemoral pain syndrome. Int J Sports Phys Ther.

2011;6:285-296.

30. McMoreland A, O’Sullivan K, Sainsbury D, et al. No deficit in hip isometric strength or concentric endurance in young females with mild

40. Dolak KL, Silkman C, Medina McKeon J, et al. Hip strengthening prior to functional exercises reduces pain sooner than quadriceps strengthening in females with patellofemoral pain syndrome: a randomized clinical trial. J Orthop Sports Phys Ther.

2011;41:560-570.

41. Earl JE, Hoch AZ. A proximal strengthening program improves pain, function, and biomechanics in women with patellofemoral pain syndrome. Am J Sports Med. 2011;39:154-163.

42. Ferber R, Kendall KD, Farr L. Changes in knee biomechanics after a hip-abductor strengthening protocol for runners with patellofemoral pain syndrome. J Athl Train. 2011;46:142-149.

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43. Khayambashi K, Mohammadkhani Z, Ghaznavi K, et al. The effects of isolated hip abductor and external rotator muscle strengthening on pain, health status, and hip strength in females with patellofemoral pain: a randomized controlled trial. J Orthop Sports Phys Ther. 2012;42(1):22-29.

45. Krause DA, Schlagel SJ, Stember BM, et al. Influence of lever arm and stabilization on measures of hip abduction and adduction torque obtained by handheld dynamometry. Arch Phys Med Rehabil.

2007;88:37-42.

46. Thorborg K, Petersen J, Magnusson SP, et al. Clinical assessment of hip strength using a hand-held dynamometer is reliable. Scand J Med Sci Sports.

2010;20:493-501.

44. Kollock RO Jr, Onate JA, Van Lunen B. The reliability of portable fixed dynamometry during hip and knee strength assessments. J Athl Train.

2010;45:349-356. http://dx.doi.org/10.4085/10626050-45.4.349.

Appendix A. Combinations PubMed of keywords forPEDro searches in varied Databases.

ScienceDirect

Ebscohost 42

Combinations of keywords ("Patellofemoral Pain Syndrome" OR "Anterior Knee Pain”) AND ("Muscle Strength" OR "Muscle Endurance”)

85

("Hip" OR "Muscle Strength" OR "Muscle Endurance”) AND ("Patellofemoral Pain Syndrome" OR "Anterior Knee Pain”)

195

("Patellofemoral Pain Syndrome" OR "Anterior Knee Pain”) AND ("Muscle Strength" OR "Muscle Endurance”) AND "Hip"

40

("Hip" OR "Muscle Strength" OR "Muscle Endurance” OR "Muscle Endurance”) AND ("Patellofemoral Pain Syndrome" OR "Anterior Knee Pain”) AND "Female"

146

("Hip" AND "Muscle Strength" OR "Muscle Endurance”) AND ("Patellofemoral Pain Syndrome" OR "Anterior Knee Pain”) AND "Female"

39

0

0

9

Total

505

8

8

165

8

8

40

43 44

0

0

73

45 46 47

0

0

22

48 49 0

0

21

50 51 52

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Appendix B. Outcomes and mean differences of hip muscle strength and endurance.

Study

Modalities

Outcome

MD (95% CI)

Isokinetic strength (eccentric) at 30°/s, (Nm/kg) x 100 Isometric strength, (Nm/N.m) x 100

PFPS, 88.89 ±10.27 Control, 123.37 ±5.85 P = .008 PFPS, 23 ±6 Control, 30±10 P = .0006 PFPS, 29 ±8 Control, 36.8±6 P = .010 Injured leg, 29±8 Noninjured leg 33±7 P = .003 PFPS, 23.3 ±6.9 Control, 31.4±6.2 P < .01 PFPS, 11.7 ±4.2 Control, 14.6±2.9 P < .002 Injured leg, 11.7±4.2 Noninjured leg 14.8 ±4.1 P < .002 Bilateral PFPS, 9.6 ±2.8 Control, 14.6 ±2.9 P < .0001 PFPS, 114.73 ±18.61 Control, 107.64 ±23.54 P = .42 PFPS, 493.69 ±174.25 Control, 492.4 ±135.2 P = .98 PFPS, 56 ±13 Control, 73 ±15 P < .001 PFPS, 16 ±8 Control, 22±3 P = .007 Injured leg, 16±8 Noninjured leg 20.5±NM PFPS, 139 ±41 Control, 162±26 P = .04 PFPS, 21.1 ±NM Control, 24.9 ±NM P = .05

-34.48 (-41.81, -27.15)

PFPS, 170.96 ±13,43 Control, 197.44 ±12,11 P =.009 PFPS, 19.8 ±7 Control, 23.6 ±4 P = .087

-26.48 (-37.69, -15.27)

Abduction Baldon et al31 Bolgla et al7 Cichanowski et al18

Isometric strength, %BW

Cichanowski et al18

Isometric strength, %BW

Ireland et al21

Isometric strength, %BW

Magalhaes et al32

Isometric strength, %BW

Magalhaes et al32

Isometric strength, %BW

Magalhaes et al 32

Isometric strength, %BW

McMoreland et al30

Isometric strength, Nm/kg x 100

McMoreland et al30

Isokinetic endurance (concentric) at 30°/s, j

Nakagawa et al33

Robinson and Nee22

Isokinetic strength (eccentric) at 30°/s, (Nm/kg.m)x100 Isometric strength, %BW

Robinson and Nee22

Isometric strength, %BW

Souza and Powers27

Isometric strength, Nm/kg x 100

Willson and Davis34

Isometric strength, %BW

-7.00 (-12.39, -1.61) -7.80 (-13.24, -2.36) -4.00 (-9.78, 1.78)

-8.10 (-12.79, -3.41)

-2.90 (-4.34, -1.46)

-3.10 [-5.26, -0.94]

-5.00 (-6.30, -3.70)

7.09 (-9.89, 24.07)

1.29 (-123.50, 126.08) -17.00 (-25.70, -8.30)

-6.00 (-11.30, -0.70) - 4.5

-23.00 (-44.83, -1.17) -3.8

Adduction Baldon et al31 Cichanowski et al18

Isokinetic strength (eccentric) at 30°/s, (Nm/kg) x 100 Isometric strength, %BW

-3.80 (-8.18, 0.58)

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Appendix B. (Continued) Cichanowski et al18

Isometric strength, %BW

Magalhaes et al32

Isometric strength, %BW

Magalhaes et al32

Isometric strength, %BW

Magalhaes et al32

Isometric strength, %BW

Injured leg, 19.8±7 Noninjured leg, 19.5 ±5 P = .65 PFPS, 14.1 ±5.7 Control, 15.1±3.7 P = NS Injured leg, 14.1±5.7 Noninjured leg 14.0 ±5.2 P > .05 Bilateral PFPS, 11.4 ±3.3 Control, 15.1 ±3.7 P < .0001

-0.30 (-4.38, 4.98)

PFPS, 51.69 ±2.98 Control, 51.48 ±3.81 P = .96 PFPS, 11 ±3 Control, 15 ±3 P = .002 PFPS, 17 ±4 Control, 20.1 ±3 P = .033 Injured leg, 17±4 Noninjured leg, 18.2 ±4 P = .049 PFPS, 10.8 ±4 Control, 16.8 ±5.5 P < .001 PFPS, 12.7 ±4.1 Control, 14.5 ±3.5 P < .01

0.21 (-2.79, 3.21)

Injured leg, 12.7±4.1 Noninjured leg 13.8 ±3.9 P > .05 Bilateral PFPS, 12.1 ±3.9 Control, 14.5 ±3.5 P < .0001 PFPS, 60.7 ±8.38 Control, 65.21 ±10.55 P = .26 PFPS, 448.24 ±95.76 Control, 481.03 ±138.38 P = .51 PFPS, 35 ±0.7 Control, 44 ± 0.6 P < .0001 PFPS, 16 ±6 Control, 23 ±4 P = .004

-1.10 (-3.16, 0.96)

-1.00 (-2.88, 0.88)

0.11 [-2.72, 2.94]

-3.70 (-5.28, -2.12)

External rotation Baldon et al31 Bolgla et al7

Isokinetic strength (eccentric) at 30°/s, (Nm/kg) x 100 Isometric strength, (Nm/N.m) x 100

Cichanowski et al18

Isometric strength, %BW

Cichanowski et al18

Isometric strength, %BW

Ireland et al21

Isometric strength, %BW

Magalhaes et al32

Isometric strength, %BW

Magalhaes et al32

Isometric strength, %BW

Magalhaes et al32

Isometric strength, %BW

McMoreland et al30

Isometric strength, Nm/kg x 100

McMoreland et al30

Isokinetic endurance (concentric) at 30°/s, j

Nakagawa et al33

Isokinetic strength (eccentric) at 30°/s, (Nm/kg.m) x 100 Isometric strength, %BW

Robinson and Nee22

-4.00 (-5.96, -2.04)

-3.10 (-5.82, -0.38)

-1.20 (-4.28, 1.88)

-6.00 (-9.44, -2.56)

-1.80 (-3.29, -0.31)

-2.40 (-4.12, -0.68)

-4.51 (-12.13, 3.11) -32.79 (-125.69, 60.11)

- 9.00 (-13.04, -4.96).

-7.00 (-11.47, -2.53)

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Appendix B. (Continued) Robinson and Isometric strength, Nee22 %BW Souza and Powers27

Isometric strength, Nm/kg x 100

Willson and Davis34

Isometric strength, %BW

Injured leg, 16±6 Noninjured leg 20±NM PFPS, 56 ±13 Control, 69 ±11 P = .002 PFPS, 9.1 ±NM Control, 10.8 ±NM P = .04

-4

PFPS, 113.30 ± 8.33 Control, 122.51 ±9.20 P = .47 PFPS, 17.9 ±4 Control, 21.1 ±3 P = .049 Injured leg, 17.9±4 Noninjured leg, 19 ±4 P = .11 PFPS, 13.6 ±4.4 Control, 14.3 ±3.1 P < .0001 Injured leg, 13.6±4.4 Noninjured leg 14.8 ±4.3 P > .05 Bilateral PFPS, 12.7 ±3.8 Control, 14.3 ±3.1 P < .0001 PFPS, 85.3 ±16.12 Control, 89.97 ±21.96 P = .56 PFPS, 694.42 ±186.15 Control, 656.5 ±191.6 P = .42

-9.21 (-16.90, -1.52)

PFPS, 27.4 ±7 Control, 32.9 ±5 P = .033 Injured leg, 27.4±7 Noninjured leg, 28.2 ±6 P = .46 PFPS, 16.3 ±6 Control, 19.4 ±4.3 P < .0001 Injured leg, 16.3±6 Noninjured leg 18.5 ±5.5 P > .05 Bilateral PFPS, 14.9. ±4.3 Control, 19.4 ±4.3 P < .0001

-5.50 (-10.18, -0.82)

-13.00 (-20.66, -5.34) -1.7

Internal rotation Baldon et al31 Cichanowski et al18

Isokinetic strength (eccentric) at 30°/s, (Nm/kg) x 100 Isometric strength, %BW

Cichanowski et al18

Isometric strength, %BW

Magalhaes et al32

Isometric strength, %BW

Magalhaes et al32

Isometric strength, %BW

Magalhaes et al32

Isometric strength, %BW

McMoreland et al30

Isometric strength, Nm/kg x 100

McMoreland et al30

Isokinetic endurance (concentric) at 30°/s, j

-3.20 (-5.92, -0.48)

-1.10 (-4.18, 1.98)

-0.70 (-2.19, 0.79)

-1.20 (-3.43, 1.03)

-1.60 [-3.23, 0.03]

-4.67 (-20.08, 10.74)

37.92 (-113.22, 189.06)

Flexion Cichanowski et al18

Isometric strength, %BW

Cichanowski et al18

Isometric strength, %BW

Magalhaes et al32

Isometric strength, %BW

Magalhaes et al32

Isometric strength, %BW

Magalhaes et al32

Isometric strength, %BW

-0.80 (-5.81, 4.21)

-3.10 (-5.15, -1.05)

-2.20 (-5.18, 0.78)

-4.50 (-6.47, -2.53)

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Appendix B. (Continued) Extension Cichanowski et al18

Isometric strength, %BW

Cichanowski et al18

Isometric strength, %BW

Magalhaes et al32

Isometric strength, %BW

Magalhaes et al32

Isometric strength, %BW

Magalhaes et al32

Isometric strength, %BW

Robinson and Nee22

Isometric strength, %BW

Souza and Powers27

Isometric strength, Nm/kg x 100

Souza and Powers27

Isokinetic strength (eccentric) at 10°/s, Nm/kg x 100 Isokinetic strength (concentric) at 10°/s, Nm/kg x 100 Isotonic endurance , total of repetitions

Souza and Powers27 Souza and Powers27

PFPS, 30.4 ±8 Control, 36.3 ±5 P = .029 Injured leg, 30.4±8 Noninjured leg, 30.9 ±9 P = .56 PFPS, 19.1 ±10 Control, 21.8 ±5.6 P < .0001 Injured leg, 19.1±10 Noninjured leg 20.6 ±10 P > .05 Bilateral PFPS, 15.8 ±9.0 Control, 21.8 ±5.6 P < .0001 Injured leg, 23±9 Noninjured leg, 32 ±NM PFPS, 198 ±50 Control, 235 ±38 P = .01 PFPS, 87 ±34 Control, 92 ±27 P = .59 PFPS, 78 ±28 Control, 94 ±15 P = .03 PFPS, 16.6 ±7.5 Control, 31.9 ±7.8

-5.90 (-11.03, -0.77)

-0.50 (-7.05, 6.05)

-2.70 (-5.88, 0.48)

-1.50 (-6.60, 3.60)

-6.42 (-10.04, -2.80)

-9 -37.00 (-65.24, -8.76) -5.00 (-24.52, 14.52)

-16.00(-30.28, -1.72)

- 15.30 (-20.17, 10.43)

Abbreviations: BMI=body mass index; BW=body weight; CI=confidence interval; M= mean difference; PFPS=patellofemoral pain syndrome

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IJSPT

ORIGINAL RESEARCH

INJURY RISK IS ALTERED BY PREVIOUS INJURY: A SYSTEMATIC REVIEW OF THE LITERATURE AND PRESENTATION OF CAUSATIVE NEUROMUSCULAR FACTORS Jessica Fulton, PT, DPT, HFS1 Kathryn Wright, PT, DPT1 Margaret Kelly, PT, DPT, CSCS1 Britanee Zebrosky, PT, DPT, CSCS1 Matthew Zanis, PT, DPT, ATC, CSCS1 Corey Drvol, PT, DPT1 Robert Butler, PT, PhD1

ABSTRACT Background: Active adults commonly present with lower extremity (LE) injuries from a variety of professional and amateur sports activities. Decreased LE function significantly alters daily life and subsequent injuries increase this impact. The purpose of this systematic review was to examine the association between previous injury and the risk of re-injury, and to describe the changes in kinematics and motor programming that may contribute to this relationship.

Methods: A preliminary search was conducted to determine the four most common LE injuries on PubMed, CINAHL and Web of Science. These injuries, in a healthy active adult population, were hamstring strain (HS), anterior cruciate ligament injury (ACL), achilles tendon pathology, and ankle sprain. After these injuries were established, the search for this systematic review found evidence relating these injuries to re-injury. Articles related to degenerative changes were excluded. Twenty-six articles were included in the systematic review detailing the risk of re-injury from a previous injury and were graded for quality.

Results: ACL injury was linked to a successive injury of the same ACL, and other injuries in the LE. HS was associated with subsequent ipsilateral HS and knee injuries. Previous achilles tendon rupture increased the risk of an analogous injury on the contralateral side. An ankle sprain was associated with a re-injury of either the ipsilateral or the contralateral ankle. Post-injury changes were present in strength, proprioception, and kinematics, which may have led to overall changes in motor control and function.

Conclusion: This review provides insight into the changes occurring following common LE injuries, how these changes potentially affect risk for future injury, and address the needs of the active adult population in rehabilitation.

Clinical Relevance: Current research on previous injury and re-injury is of high quality, but scarce quantity. Deficits following an injury are known, but how these deficits correlate or lead to re-injury requires further exploration.

Keywords: Injury, motor programming, re-injury Level of Evidence: 1

1

Duke University, Durham, NC, USA

CORRESPONDING AUTHOR Robert J. Butler, PT, PhD Doctor of Physical Therapy Division Duke University DUMC 104002 Durham, NC 27705 Phone: 919.681.7225 Fax: 919.684.1846 E-mail: robert.butler@duke.edu

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INTRODUCTION Attempts at healthy living spur an increase in activity in the adult population and consequently, also in the risk for injury. Traumatic and atraumatic injuries are a common consequence of new or increased activity. Following injury, patients often experience decreased functional capacity. Several authors have described previous injury as the greatest risk factor for future injury secondary to changes along the kinematic chain, i.e. proprioceptive deficits, reduced range of motion, excessive flexibility, and scar tissue accumulation.1-3 Knowledge of these intrinsic changes may benefit rehabilitation models for active adults with the potential of reducing re-injury rates and improving quality of life, while also helping to lower overall medical costs.

A recent systematic review of the literature (SR) determined that the most common lower extremity injuries in a healthy active adult population were, in no specific order, hamstring strain (HS), anterior cruciate ligament (ACL) injury, achilles tendon pathology, and ankle sprain. Due to the intricate relationships between joints during movement of the lower extremity, changes often occur at sites other than the initial point of injury.4 Regional interdependence is an important key to understanding how anatomic variables occurring within the kinetic chain may contribute to re-injury.5 Previously, researchers have examined these common injuries and the subsequent changes in kinematics and motor programming.2,6-9 However, the connection of these changes to subsequent lower extremity injuries has not been examined.

The purpose of this systematic review is to establish the most common lower extremity injuries and the risk of re-injury or subsequent injury as it relates to alterations in kinematics and motor programing.

This review combines an analysis of established data on the risk of re-injury following a lower extremity injury with a qualitative discussion on the factors that contribute to this relationship. By developing a greater understanding of the kinematic and motor programming changes following injury, the authors hope to illuminate how one injury to the lower extremity may increase the risk for re-injury or subsequent injury. By integrating information on the relationship between injury and subsequent injury,

rehabilitation could focus on not only the immediate injury, but also potentially reducing future injury.

METHODS A five-stage process was used to select studies. The first stage involved a search on PubMed, CINAHL, and Web of Science using the search terms “injuries AND lower extremity AND prevalence AND adults”.

This search provided data that was utilized to select the four most common injuries that occur in the lower extremities. This search yielded 158 articles of which 17 were ruled in based on a title and abstract screen. From here the articles were read for full text and six articles were chosen for their specific research on injury prevalence according to these search terms. From the information presented in these articles, the four most common musculoskeletal injuries were determined to be ankle sprain, ACL injury, HS, and achilles injury.

The second search for the topic of the current review utilized the terms “ankle sprain OR ACL injury OR Achilles injury OR hamstring strain AND previous injury” in PubMed and CINAHL (Figure 1). A filter of “ages 19-44” was applied to this search. Next, two independent reviewers performed an initial assessment of the identified papers based on title. For all assessments, inclusion criteria included articles dealing with an active, healthy, athletic population (including military personnel); directly related to one of the four selected injuries; concerned with motor control or kinematics; as well as describing injury as a result of re-injury. Articles dealing with osteoarthritis or degenerative injury were excluded. Articles written in languages other than English were excluded, unless a translated version was available. These criteria were chosen based on the immense return utilizing the selected search terms and the need to specify the population most likely at risk for re-injury. Second, two independent reviewers performed an assessment based on the articles’ abstract. For both the title and abstract assessments, all articles that received a “Yes” rating by one reviewer were kept. Finally, a full text review was performed, dividing articles equally among three teams of reviewers. Each team of two independent reviewers assessed each set. Any articles published before the year 2000 were excluded.

Articles that received a split rating (one “Yes” and

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Figure 1. Flow of literature search and review of studies

one “No”) were reviewed by another independent reviewer who made the final decision.

Four independent reviewers using the Quality Assessment of Diagnostic Accuracy Studies (QUADAS) tool completed grading of the articles regarding injury as a risk of re-injury.10 The QUADAS is a 14-question tool to determine the internal and external validity of a study. The questions are answered “yes, no, N/A or unclear”, for which one point is awarded for every “yes” answer. The QUADAS examines such biases as spectrum, selection, disease progression, and verification bias. Two reviewers graded articles related to ACL injuries and HS, while two other reviewers graded articles regarding Achilles and ankle injuries. After independently grading these articles, each pair came to a consensus on scoring criteria for each article. A score of 10 or more was considered “high quality, low risk of bias” and a score below 10 was considered “low quality, high risk of bias”.11 Cook states, “systematic reviews that use the QUADAS instrument provide a qualitative assessment of design with recognition that weaknesses in selected regions may alter some test findings more than others.”10(p. 98) Thus, with this grading

system it can be stated that despite possible bias(es) existing within an article, overall quality could still be considered to be good. One of the articles, Friel et al,12 was not evaluated using the QUADAS due to the study design being Ex-post Facto. Therefore, two independent reviewers individually graded this article as “poor”, “fair”, or “good” and came to a consensus on the grading of the article.

All five articles for ACL injury relating to subsequent injury were of high quality and low risk of bias, with scores ranging from 10 to 12 based on the QUADAS criteria. Of the seven HS related studies; only one was graded to be of low quality and high risk of bias, with a score of 8. The other articles ranged from a score of 10 to 13, indicating high quality and low risk of bias. Similarly, high quality and low risk of bias was evident in the three articles for the Achilles group, with scores ranging from 11 to 12, and the ankle injury group where the ten studies scores ranged from 11 to 13. With these findings and analyses, the authors concluded that appropriate designs have been formulated and implemented resulting in outcomes that could be used for evidence-based practice.

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RESULTS Hamstring Strain Five articles were found correlating HS with subsequent strains of the same muscle group (Appendix 1). In a study analyzing elite level Australian football players, the authors concluded that a HS strain within the previous 12 months was a strong predictor of future HS.3 The football players were 4.3 times more likely to incur another HS as opposed to players without history of previous HS.3 In a similar population of Australian football players and track and field athletes, 34% of HS were recurrences and previous strain was the most common reason for subsequent HS.13 In addition, 27% of all HS in the Australian Football League (AFL) were caused by previous HS, which increased the risk of recurrence by 11.6. It is unclear, however, if the cause of increased recurrence is due to accumulated microscopic muscle damage or the presence of a single injurious event.16 No matter the cause of HS, the research clearly indicates that previous HS is an important risk factor for future HS.14,15 Anterior Cruciate Ligament Injury ACL injury has been linked to a successive injury of the same ACL and other impairments or injuries in the lower extremity (Appendix 2). In one study, ACL graft ruptures occurred in 6.4% of subjects and a contralateral ACL rupture followed at a frequency of 5.7%.17 In addition to a previous injury of the ACL, activity level after the injury was indicated to predict another injury of the same or contralateral ACL.17 In elite footballers, 70% of current ACL injuries occurred on the same leg as a previous ACL injury.2 Ten percent of subjects in another study reported traumatically reinjuring their knee, resulting in disruption of the graft, between four and twelve months after ACL reconstruction.18 Research indicates that re-injury can occur to the same or contralateral ACL following an initial ACL injury, when that injury was treated conservatively or surgically. Inadequate landing force attenuation was identified as imposing abnormal forces after reconstruction on the musculoskeletal components, thus increasing the risk of re-injury.19 Achilles Tendon Injury There is little research exploring achilles tendon injury and its effect on re-injury or subsequent injury (Appendix 3). However, one article discussed that

following an Achilles tendon injury among the adult population, risk of re-injury is greater in individuals 30 years or younger.20 Another study linked previous Achilles tendon rupture to a risk of an analogous injury on the contralateral side, stating that an individual is 176 times more likely to injure the opposite side approximately 3.1 years later compared to an individual without a previous Achilles tendon pathology. The authors proposed a multifactorial explanation to this connection suggesting an increased risk due to degenerative changes, a genetic predisposition for tendon ruptures, or disuse atrophy of the contralateral tendon from overall decreased physical activity due to immobilization of the injured leg.21 Ankle Sprain In accordance with the research, a single ankle sprain is the most common injury resulting in a secondary sprain of the ipsilateral or contralateral ankle among the active adult population (Appendix 4). In a study investigating the effect of ankle sprain on recurrent ankle sprains in 202 elite Greek track athletes, there was a higher risk of re-injury for lowgrade ankle sprains as opposed to high-grade ankle sprains.22 The authors discovered that 17.8 percent of their athletes suffered a second lateral ankle sprain by the end of the follow-up period.22 In another study involving 65 professional male football players, the recurrence of a secondary ankle sprain following the same initial injury was 50 percent higher than those without a previous ankle sprain. The authors also found that 75.38 percent of these athletes had sustained multiple ankle sprains (63.27 percent in bilateral ankles; 24.49 percent in the dominant ankle only) during their entire career up until the point at which the study was concluded.23 Pefanis et al found that a previous ankle sprain was the most important statistical factor leading to a subsequent ankle sprain, increasing the occurrence by 21 percent.24 Additional research in this area has suggested that leg dominance may be a factor leading to injury. Williams and colleagues reported that in college freshman physical education students 59 percent of recurrent ankle sprains occurred in the dominant foot among 44 of the 241 participants.25 In conclusion, the results of this SR indicate that an ankle sprain is linked to both re-injury and subsequent injury to the contralateral side.

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DISCUSSION The results of this systematic review revealed a relationship between previous injury and re-injury in each lower extremity injury that was studied.

Overall, the vast majority of articles reviewed discussed this relationship in detail and suggested many possibilities for why this trend exists. Reinjury was suggested to be associated with deficits in neuromuscular factors that are present following injuries.2,3,18,21,26 The goal of this discussion will be to qualitatively examine the changes that were identified in papers examined that occurred post-injury and how they were proposed to link injury to reinjury. Following injury, researchers have identified alterations occurring in strength, proprioception, and kinematics, which have led to overall changes in motor control and function.2,13,15,25,27-35 This combination of insight may offer valuable information to clinicians for reduction of re-injury.

Strength deficits between affected and unaffected limbs as well as imbalances between muscle groups have been documented post hamstring strain, post ACL rupture, and post Achilles tendon rupture.7,9,15,27-29,33,36,37 Without recovering muscle strength of involved muscles following an initial injury, the stability of joints, biomechanics of motion, and the ability to safely participate in activity are likely compromised. Several authors suggested that incorporating strength training and standards for strength following injury is necessary in order to decrease long-term muscular deficits that could go on to affect kinematics and motor control both proximal and distal to the injury, further increasing the risk of subsequent injury.7,9,15,27-29,33,36,37 Proprioceptive deficits, altered muscular recruitment patterns, and changes in static and dynamic stability occur from altered neuronal firing and decreased sensory awareness within joint and muscle tissue following ACL rupture, Achilles tendon injury, and ankle sprains.9,19,31,38-52 Authors of papers reviewed described variations in postural sway, gait mechanics, and decreased dynamic stability within functional activities that might place individuals at higher risk for re-injury.39,40,42,48,50 Changes in strength and proprioception, which very likely occur together, contribute to the next factor

to be addressed: changes in lower extremity biomechanics following injury. The observed biomechanical changes that have been documented are changes in peak torque, altered gait mechanics, and intra-articular and intra-muscular forces (including, compressive, tensile, and shear forces) in the hamstring, ACL, and ankle.13,30,47,48,53-58 Comprehensive biomechanical evaluation of the patient is pertinent in order to correctly develop treatment strategies that positively affect vectors of force displacement within the body, with the aim of normalizing joint mechanics. Suboptimal mechanics during high-level functional tasks have at times been associated with risk of future sports injuries.59-61 The authors of this systematic review believe that by examining and addressing joint kinematics post injury, patients may have the potential to return to functional activity at a greater rate and avoid potential re-injury.

This systematic review adequately describes the major risk of re-injury post initial injury in the adult population. The high risk of re-injury described, stresses the importance of comprehensive rehabilitation that uses the theory of regional interdependence to adequately mitigate local, proximal, and distal deficits in strength, proprioception, and lower extremity mechanics.5 Future research establishing standards for the aforementioned deficits and developing rehabilitation programming that addresses these limitations is important, and it may be possible to remove the previous injury risk factor component with regard to risk of future injury. In addition to the health benefits of preventing re-injury, medical costs may also be reduced which would lower the economic burden of the initial injury.

Limitations to the study are typical of those attributed to systematic reviews. This paper focused on the four most common lower extremity injuries; however, the breadth of injuries incurred in the adult population extends beyond those examined in this research. Additionally, this research cannot be expanded beyond the active adult population. While the relationship between injury and re-injury was described, the ability to generalize the qualitatively identified variables including kinematic alterations, motor control deficits, and musculoskeletal changes to other injuries requires further exploration. To maintain the focus of this SR, the authors did not

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attempt to discuss a standardized way to examine a patient for these changes, nor was it appropriate to discuss specific interventions to treat these impairments as these components were beyond the scope of this systematic review. Although there were standardized criteria for inclusion and exclusion of articles, the selection process has inherent inter-rater reliability concerns, such that a third party reviewer was utilized if raters could not agree.

Future Studies Future research should be performed in order to determine standardized outcome tools that could be used to objectively identify changes that occur following injury that relate to the risk for future injury. Based on the current research, it appears that it would be beneficial to include outcome tools that assess a patient’s movement patterns following injury in order to optimize function from a regional interdependence approach prior to returning the patient to his/her previous level of activity. These tests may be beneficial in examining patients posttreatment to assess for functional return to activity.

Furthermore, research should be performed in order to identify the most beneficial interventions and strategies used to address changes following injury and to develop protocols to reduce risk of re-injury.

CONCLUSION In conclusion, this systematic review of the literature identified and reviewed 26 articles, which describe a relationship between injury and re-injury for the four most common lower extremity injuries. Overall, the studies on re-injury were of moderate to high quality, but the quantity of research was scarce. Evidence regarding the hamstring strain, ACL rupture, achilles tendon injury, and ankle sprain are of moderate to high quality in relation to this topic, aside from one article with a low quality rating.3 More analysis on the relationship between injury and re-injury is needed. Motor control and kinematic deficits following injury have been suggested, but their direct relation to re-injury requires further exploration.

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44. Palmieri-Smith R, McLean SG, Ashton-Miller J, Wojtys EM. Association of quadriceps and hamstrings cocontraction patterns with knee joint loading. J ATHLETIC TRAIN. 2009;44(3):256-263.

45. Palmieri-Smith R, Hopkins JT, Brown TN. Peroneal activation deficits in persons with functional ankle instability. Am J Sports Med. 2009;37(5):982-988.

46. Santilli V, Frascarelli MA, Paoloni M, et al. Peroneus longus muscle activation pattern during gait cycle in athletes affected by functional ankle instability: A surface electromyographic study. Am J Sports Med. 2005;33(8):1183-1187.

47. Mitchell A, Dyson R, Hale T, Abraham C. Biomechanics of ankle instability. part 1: Reaction time to simulated ankle sprain. Med Sci Sports Exerc.

2008;40(8):151548. Mitchell A, Dyson R, Hale T, Abraham C. Biomechanics of ankle instability. part 2: Postural sway-reaction time relationship. Med Sci Sports Exerc.

2008;40(8):1522-1528.

49. Ross SE, Guskiewicz KM. Examination of static and dynamic postural stability in individuals with functionally stable and unstable ankles. Clin J Sport Med. 2004;14(6):332-338.

50. McKeon PO, Hertel J. Spatiotemporal postural control deficits are present in those with chronic ankle instability. BMC Musculoskelet Disord.

2008;9:76.

51. Refshauge KM, Kilbreath SL, Raymond J. Deficits in detection of inversion and eversion movements among subjects with recurrent ankle sprains... including commentary by vandervoort AA with authors’ response. J Orthop Sports Phys Ther.

2003;33(4):166-176.

52. Sefton JM, Hicks-Little C, Hubbard TJ, et al.

Sensorimotor function as a predictor of chronic ankle instability. Clin Biomech. 2009;24(5):451-458.

53. DeVita P, Hortobagyi T. Functional knee brace alters predicted knee muscle and joint forces in people with ACL reconstruction during walking. J APPL BIOMECH. 2001;17(4):297-311.

54. Tecco S, Salini V, Calvisi V, et al. Effects of anterior cruciate ligament (ACL) injury on postural control and muscle activity of head, neck and trunk muscles. J Oral Rehabil. 2006;33(8):576-587.

55. Binder-Macleod B, Buchanan TS. Tibialis anterior volumes and areas in ACL-injured limbs compared with unimpaired. Med Sci Sports Exerc.

2006;38(9):1553-1557.

56. Rudolph KS, Axe MJ, Snyder-Mackler L. Dynamic stability after ACL injury: Who can hop? Knee Surg Sports Traumatol Arthrosc. 2000;8(5):262-269.

57. Paterno MV, Ford KR, Myer GD, Heyl R, Hewett TE. Limb asymmetries in landing and jumping 2 years following anterior cruciate ligament reconstruction.

Clin J Sport Med. 2007;17(4):258-262.

58. Nakasa T, Fukuhara K, Adachi N, Ochi M. The deficit of joint position sense in the chronic unstable ankle as measured by inversion angle replication error.

Arch Orthop Trauma Surg. 2008;128(5):445-449.

59. Hewett TE, Torg JS, Boden BP. Video analysis of trunk and knee motion during non-contact anterior cruciate ligament injury in female athletes: Lateral trunk and knee abduction motion are combined components of the injury mechanism. Br J Sports Med. 2009;43(6):417-422.

60. Boling MC, Padua DA, Alexander Creighton R. Concentric and eccentric torque of the hip musculature in individuals with and without patellofemoral pain. J Athl Train. 2009;44(1):7-13.

61. Ferber R, Noehren B, Hamill J, Davis IS. Competitive female runners with a history of iliotibial band syndrome demonstrate atypical hip and knee kinematics. J Orthop Sports Phys Ther. 2010;40(2):52-58.

62. Kiesel KB, Butler RJ, Plisky PJ. Prediction of injury by limited and asymmetrical fundamental movement patterns in american football players. J Sport Rehabil. 2014;23(2):88-94. doi: 63. Plisky PJ, Rauh MJ, Kaminski TW, Underwood FB. Star excursion balance test as a predictor of lower extremity injury in high school basketball players. J Orthop Sports Phys Ther. 2006;36(12):911-919.

64. Plisky PJ, Gorman PP, Butler RJ, Kiesel KB, Underwood FB, Elkins B. The reliability of an instrumented device for measuring components of the star excursion balance test. N Am J Sports Phys Ther. 2009;4(2):92-99.

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The International Journal of Sports Physical Therapy | Volume 9, Number 5 | October 2014 | Page 591

Gabbe,B.J., et al.

Fousekis,K., et al.

Predictors of hamstring injury at the elite level of Australian football (2006)

Intrinsic risk factors of non-contact quadriceps and hamstring strains in soccer: a prospective study of 100 professional players (2010) Predicting hamstring strain injury in elite athletes (2004)

59 elite male Australian football players, mean age 24 years, who missed at least one game due to injury.

44 male gaelic football players, mean age 21.2 years.

18 individuals involved in running-related sports with a previous hamstring injury, between 18-45 years old.

Warren, et al.

O'Sullivan, et al.

Silder, et al.

Clinical predictors of time to return to competition and of recurrence following hamstring strain in elite Australian footballers (2008) The relationship between previous hamstring injury and the concentric isokinetic knee muscle strength of irish gaelic footballers (2008) Effects of Prior Hamstring Strain Injury on Strength, Flexibility, and Running Mechanics (2010)

114 males from two professional Australian Football Leagues, mean age 21.6 years.

Verrall, et al.

27 athletes, 26 males & 1 female, 23 AFL players & 4 track-and-field athletes, between 19-33 years old.

222 elite male Australian football players, between 1737 years old from 6 Melbourne AFL clubs during pre-season of 2002 100 professional soccer players, between 19-28 years old, free of injury for at least 6 months prior to testing

Population (age, gender, activity)

Clinical risk factors for hamstring muscle strain (2001)

Brockett,C.L, et al.

Author

Title

Appendix 1. Hamstring Strain Re-injury Papers

"Our results suggest that, while scar tissue may be present in subjects with a prior hamstring injury, these underlying morphological changes do not appear to be discernable in terms of functional strength measures, or musculotendon stretch and neuromuscular patterns during sprinting."

"Evidence of hamstring muscle weakness and muscle strength imbalance in gaelic footballers after previous hamstring injury"

“Nine players (15%) experienced a recurrence of their hamstring injury within the first 3 weeks of returning to play”

“There was a significantly increased risk of injury with older age, being of aboriginal descent, a past history of posterior thigh injury, a past history of knee injury, and a past history of osteitis pubis.”

“If the optimum length for active tension is rather short, in terms of the muscle’s working range, it follows that more of the descending limb will be included within the working range. That, in turn, increases the risk of damage."

“For the development of hamstring strains in soccer players, two functional asymmetries of the lower limbs (isokinetic strength and leg length) are accountable, with previous history of strains in the same muscle group being rather reductive of the odds of this injury.”

"A positive hamstring injury history (sustained during the previous 12 months) was identified as the strongest predictor of subsequent hamstring injury and supports the findings of several studies.”

Main Findings

Prospective Cohort

Prospective Observational

Prospective Observational

Prospective Cohort

Controlled Laboratory Study

Cohort

Cohort

Type of study

11

10

13

12

11

13

8

QUADAS

The International Journal of Sports Physical Therapy | Volume 9, Number 5 | October 2014 | Page 592 Gerber,J.P., et al.

Mikkelsen,C., et al.

Effects of early progressive eccentric exercise on muscle size and function after anterior cruciate ligament reconstruction: a 1-year follow-up study of a randomized clinical trial (2009)

Closed kinetic chain alone compared to combined open and closed kinetic chain exercises for quadriceps strengthening after anterior cruciate ligament reconstruction with respect to return to sports: a prospective matched follow-up study (2000)

44 individuals, between 18–40 years old with a first-ever unilateral ACL injury and a healthy contralateral leg.

Randomly assigned: Group 1 trained with CKC and Group 2 trained with CKC for first 6 weeks, then OKC for quadriceps muscle.

40 patients with ACL-R, between 1850 years old, who were moderately active prior to injury. Randomly assigned: Group 1 receiving early progressive eccentric exercise and Group 2 receiving standard rehab.

100 athletes, 67 males & 33 females, mean age 28 years. Athletes playing in sports at regional/national levels/rec sports at least 3x/week, with normal contralateral knee, those w/ part. meniscectomies 56 individuals, 36 males & 20 females, between 15-45 years old who were ACL deficient with an uninjured contralateral extremity.

Gobbi,A., et al.

Ageberg, et al.

310 Male Swedish League players, mean age 25 years.

24 ACL injured, 286 ACL healthy.

Population (age, gender, activity)

Walde ́n, M., et al.

Author

Normalized motor function but impaired sensory function after unilateral non-reconstructed ACL injury: patients compared with uninjured controls (2008)

High risk of new knee injury in elite footballers with previous anterior cruciate ligament injury (2006) Factors affecting return to sports after anterior cruciate ligament reconstruction with patellar tendon and hamstring graft: a prospective clinical investigation (2006)

Title

Appendix 2. ACL Re-Injury Papers

Of the 22 patients in group 2, “12 returned to sport at the same level as before the injury, eight patients had reduced their activity level and/or changed to a less knee demanding sport due to impaired knee function in three patients, social and family reasons in three, and the fear of reinjuring the knee in two. One patient did not return to any type of sport due to a new knee injury of the contralateral leg. One patient was not physically active either before or after ACL reconstruction.”

“Of those not returning for 1-year follow-up, 4 participants traumatically reinjured their involved knee between 4 and 12 months following initial ACLR, causing graft disruption.”

“The impact of these findings on the risk of sustaining re-injuries requires further studies, and there may be a breakpoint at which the discrepancy between motor and sensory function becomes a risk factor during more strenuous activity.”

“Total, 715 injuries were recorded, and 625 (87%) were located to the lower limbs. Of the injuries to the lower extremities in the ACL injured group, 70% (38/54) affected a limb with a previous ACL injury.”

“Two patients presented with persistent clicking and catching during the first year post-ACL…In another case (HT graft), re-injury to the operated knee was documented”

Main Findings

Randomized Control Trial

Randomized Control Trial

Cross-sectional

Longitudinal

Prospective Cohort

Type of study

11

11

12

10

12

QUADAS

The International Journal of Sports Physical Therapy | Volume 9, Number 5 | October 2014 | Page 593

Author

Bressel, et al.

Aroen, et al.

Mahieu, et al.

Title

Biomechanical Behavior of the Plantar Flexor Muscle-Tendon Unit after an Achilles Tendon Rupture (2001)

Contralateral tendon rupture risk is increased in individuals with a previous Achilles tendon rupture (2004)

Intrinsic Risk Factors for the Development of Achilles Tendon Overuse Injury (2006) 69 male officer cadets at the Belgian Royal Military academy, mean age 18 years.

168 patients, 142 males & 26 females, median age 38.5 years at time of injury, who had Achilles rupture between 1990 and 1997 at a Norway hospital.

40 individuals, 26 males & 14 females, mean age 51.4 years, volunteered for the study. All subjects were involved in at least light/ recreational activity and had ruptured their Achilles tendon more than 1 year before the study.

Population (age, gender, activity)

Appendix 3. Achilles Tendon Re-injury Papers

10/69 had Achilles overuse injuries during the 6 weeks of basic training. Those with lower plantar flexor strength and increased dorsiflexion ROM were at greater risk of this injury. Authors hypothesized that stronger muscle strength produces stronger tendons that could better deal with excessive force.

Greatly increased risk of rupture of contralateral Achilles tendon in those who had a previous rupture on one side.

The authors proposed that this could be due to a genetic predisposition for tendon ruptures, that the injury is caused by degenerative changes, or that disuse atrophy of the contralateral tendon due to immobilization of the injured leg contributed to the injury.

Stiffness and viscoelastic properties, such as torque relaxation, were similar between the involved and uninvolved limbs. However, other measurements, such as peak passive torque, calf circumference, and maximal isometric plantar flexor torque, were greater in the uninvolved limb. Increased values for stiffness may predispose the muscle-tendon unit to further damage.

Main findings

Cohort (Prospective)

Retrospective Self-Report Questionnaire

Experimental

Type of study

11

11

12

QUADAS

The International Journal of Sports Physical Therapy | Volume 9, Number 5 | October 2014 | Page 594 Edouard, et al.

Denegar, et al.

Gutierrez, et al.

Hubbard, et al.

Hertel, et al.

Fousekis, et al.

The Effect of Lateral Ankle Sprain on Dorsiflexion Range of Motion, Posterior Talar Glide, and Joint Laxity (2002)

Examining Neuromuscular Control During Landings on a Supinating Platform in Persons With and Without Ankle Instability (2011)

Mechanical Instability After an Acute Lateral Ankle Sprain (2009)

Serial testing of postural control after acute lateral ankle sprain (2001)

Intrinsic Risk Factors of Noncontact Ankle Sprains in Soccer (2012)

Author

Invertor and evertor strength in track and field athletes with functional ankle instability (2011)

Title

Appendix 4. Ankle Re-injury Papers

100 professional soccer players, mean age 23.6 years who had sustained no injury for the past 6 months were assessed for ankle joint asymmetries

16 subjects with a first-time acute unilateral ankle sprain, 7 males & 9 females, mean age 19.5 years. 16 healthy controls, 7 males & 9 females, mean age 20.4 years.

17 young adults, 9 males & 8 females, mean age 21.8 years who sustained unilateral acute mild to moderate lateral ankle sprains

45 active, healthy participants between 18-30 years old were divided into 3 groups: ankle instability, lateral ankle sprain, and control

12 athletes, 5 males & 7 females, between 18-22 years old with a history of lateral ankle sprain within the last 6 months who had returned to sport participation

Track and field female athletes between 15-40 years old with a history of lateral ankles sprains

Population (age, gender, activity)

Individuals with postural control impairments are likely to have larger COP excursions and thus, larger sum of excursions throughout a trial. Elevated measures of postural control during static SLS have not been shown to predict recurrent ankle sprain with prolonged functional ankle instability. However, the lack of balance training after acute LAS appears to predispose ankle-injured subjects to recurrent sprain The logistic regression analysis revealed 3 significant predictors of noncontact ankle sprains: (A) eccentric isokinetic strength asymmetries of ankle dorsal and plantar flexors; (B) increased BMI; and (C) increased body weight.

This study found that there is not an increased risk for lateral ankle ligament injury after suffering a prior ankle injury.

The lack of significant differences in mechanical laxity over an 8-week period suggests that natural recovery of laxity takes longer than 8 weeks.

When landing on a device built to simulate the mechanism of a lateral ankle sprain (supination), the ankle instability group displayed significantly increased preparatory and reactive peroneal activation, while the Lateral Ankle Sprain group demonstrated increased preparatory tibialis anterior muscle activation.

The evertor muscle strength was higher than the invertor muscle strength in the dominant side for all groups, except for the group with a previous history of ankle sprain. An elevated ankle Evertor/Invertor Ratio (> 1.0) has been identified as an important indicator of ankle sprain susceptibility; otherwise, it could be an invertor strength weakness in subjects with FAI. Residual ligamentous laxity was commonly found following lateral ankle sprain. Dorsiflexion range of motion was restored in the population studied despite evidence of restricted posterior glide of the talocrural joint. Although restoration of physiological range of motion was achieved, residual joint dysfunction persisted.

Main Findings

Cohort

12

11

11

Cohort

Longitudinal

12

12

12

QUADAS

Controlled Laboratory Study

Retrospective Study

Cross-Sectional

Type of study

The International Journal of Sports Physical Therapy | Volume 9, Number 5 | October 2014 | Page 595 202 elite male and female Greek track athletes with acute lateral ankle sprains

Malliaropoulos, et al.

Pefanis, et al.

Pefanis, et al.

Willems, et al.

Reinjury After Acute Lateral Ankle Sprains in Elite Track and Field Athletes (2009)

Tibiofemoral angle and its relation to ankle sprain occurrence (2009)

The effect of Q-angle on ankle sprain occurrence (2009)

Intrinsic risk factors for inversion ankle sprains in male subjects (2005)

241 male Phys. Ed. students, mean age 18.3 years who were freshman at the Ghent University.

45 high-level basketball, soccer, and volleyball male athletes, mean age 23 years.

45 high-level basketball, soccer, and volleyball male athletes, mean age 23 years.

Convenience sample of 23 individuals, between 18-52 years old with a history of at least 2 ankle sprains to the same side

Friel, et al.

Ipsilateral Hip Abductor Weakness After Inversion Ankle Sprain (2006)

Population (age, gender, activity)

Author

Title

Appendix 4. Ankle Re-injury Papers (continued)

The factors contributing more to an ankle sprain were previous similar injury, followed by BMI, and age. TFA was proven to be statistically non-significant and does not seem to be a factor that could increase the probability of spraining an ankle.

The factors contributing more to an ankle sprain were previous similar injury, followed by BMI and age. Q-angle was shown to be statistically non-significant and does not seem to be a factor that could increase the chances of spraining an ankle.

44 of the 241 sustained an inversion sprain within the 1-3 year follow-up, 4 sprained both ankles. Those with slower running speed, less cardiorespiratory endurance, less balance, decreased dorsiflexion muscle strength, decreased dorsiflexion ROM, less coordination, and faster reaction of the tibialis anterior and gastrocnemius muscles are at a greater risk of ankle sprains.

Low-grade ankle sprains result in a higher risk of re-injury than high-grade ankle sprains at a 24-month follow-up.

Grade II injuries showed a significantly higher rate of reinjury than grades I and III A. There was no significant difference in time between original injury and re-injury based on grade of injury.

Significant weakness in the hip abductor muscles on the involved side as compared with the uninvolved limb of subjects was found with chronic ankle sprain, which can contribute to increased risk for re-injury.

Main Findings

Prospective Cohort Study

Prospective

Prospective

Cohort (Prognosis)

Ex-Post Facto Design

Type of study

13

11

11

12

N/A

QUADAS

IJSPT

ORIGINAL RESEARCH

NORMATIVE DATA FOR HOP TESTS IN HIGH SCHOOL AND COLLEGIATE BASKETBALL AND SOCCER PLAYERS Betsy A Myers, PT, DHS, MPT, OCS, CWS, CLT1 Walter L Jenkins, PT, DHS, LATC, ATC2 Clyde Killian, PT, PhD3 Peter Rundquist, PT, PhD4

ABSTRACT Purpose/Background: Objective, reliable, and valid functional tests may assist with the decision-making process for rehabilitation as well as assist in pre-participation screening for targeted interventions to prevent noncontact lower extremity injuries. The purpose of this study was to determine normative values in high school and college basketball and soccer players for four hop tests: the single hop for distance, the triple hop for distance, the crossover hop for distance, and the 6-m timed hop.

Methods: A sample of convenience of 372 (185 females, 187 males) healthy high school and collegiate student-athletes were included in the study (mean age 17.37 years, range 14-24): 200 were soccer players and 172 were basketball players. Limb dominance was determined based on which extremity participants would choose to kick a ball for distance. A coin flip was used to determine which limb was tested first. Hop test order was randomized using a Latin square design. Participants performed one practice hop and three measured hops for each hop test on each limb. The average hop score for each limb was used for calculations.

Results: Significant differences in test performance were found between sexes and levels of competition, p < 0.0005, with males performing better than females and collegiate athletes performing better than high school athletes for all hop tests. There were no clinically relevant differences between dominant sports.

There were also no clinically relevant differences between dominant and non-dominant limbs. Normative values for each hop test were proposed, based on sex and level of competition.

Conclusions: These findings indicate that separate hop test standards should be used based on participant sex and level of competition. While some statistically significant differences were found between limbs, these differences did not appear to be functionally relevant. Further studies are needed to determine if sport-specific normative hop test values should be utilized and to examine normal limb symmetry indices in specific populations.

Levels of Evidence: 2A Key Words: ACL, return to sport, hop test, functional performance testing

1

St. Francis Health System, Tulsa, OK, USA Eastern Carolina University, Greenville, NC, USA 3 University of Indianapolis, Indianapolis, IN, USA 4 Concordia University, St. Paul, MN, USA 2

This study was not supported by any grant funding. This study received Institutional Review Board approval from the University of Indianapolis.

CORRESPONDING AUTHOR Betsy Myers St. Francis Health System, Tulsa, OK, USA E-mail: betsymyers@cox.net

The International Journal of Sports Physical Therapy | Volume 9, Number 5 | October 2014 | Page 596

INTRODUCTION More than 7.4 million U.S. high school students participate in competitive athletics today.1 The overall injury rate per 1,000 hours of athletic exposure was 1.97 for high school athletes1 and 12 for collegiate athletes.2 Fifty-seven to 70% of injuries occur in the lower extremity.1,3-8 Some sports have an inherently higher risk for injury, such as football and ice hockey, where collision-related injuries are common. However, many injuries occur without contact.5-8 The most common, and the most severe, non-contact injury in terms of time lost from competition is an anterior cruciate ligament (ACL) rupture. Many noncontact ACL injuries may be preventable9,10 through improvements in athlete neuromuscular control, skill performance, and conditioning.

An ACL rupture can be devastating to an athleteâ&#x20AC;&#x2122;s competitive career. While one study noted that 65 - 80% of athletes who sustain an ACL tear returned to play within one year of ACL reconstruction (ACLR),11 a more recent study12 revealed that only 34% of athletes returned to full competition, while another 33% were only able to partially return to competition. Thirteen percent of athletes discontinued training due to their ACL injury. The risk of a repeat ACL injury or contralateral ACL injury in returning athletes ranges from 3-15%.13-17 Last, many athletes report their ACL injury was the reason for their eventual early retirement.18 Given these high rates of ACL injuries, repeat injuries, and persisting functional deficits, there is a need for better athlete preparation, rehabilitation, and safer return to sport.16 In their recent systematic review of the literature, Barber-Westin and Noyes illustrated this knowledge gap by noting that 40% of investigators failed to use any criteria to determine when an athlete may be ready to return to sport after ACLR.19 Another 32% of investigators noted time post-surgery as the sole criteria.19 When choosing criteria, clinicians must choose tests that are objective, reliable, and valid. In addition, tests need to be practical in terms of the equipment and time required. The tests should also entail little or no risk to the rehabilitating athlete. Criteria should also have accepted normative values in order to allow relevant comparisons.20 Historically, impairmentbased testing has been the norm. However, it is now

known that impairments such as knee joint range of motion,21 manually tested joint laxity,21-23 proprioception testing,24 and isotonic25,26 or isokinetic21,27-29 strength testing have little correlation with successful return to sport.

Functional performance tests are meant to simulate a portion of the competitive environment in a controlled fashion. While many authors support the use of functional testing to determine functional performance,27-30 the question of what functional tests are most appropriate remains unanswered. Given current knowledge that the uninvolved side can compensate for the involved extremity,31,32 bipedal tasks may mask the impairments and functional deficits that occur after unilateral lower extremity injuries.33-35 Hop tests, the single hop for distance, the triple hop for distance, the crossover hop for distance, and the 6-m timed hop, are unilateral functional performance tests with extensive research supporting their reliability and/or validity.

Because of the disproportionate percentage of female athletes with ACL injuries, it is important to identify if there are any differences in hop test performance between sexes. Maturation has been found to lead to sex differences in landing forces,36 vertical jump performance,36-38 and cutting.39 Barber-Westinâ&#x20AC;&#x2122;s study40 demonstrated an interaction between age and sex for both drop landing and crossover hopping. Therefore, it would appear wise to compare hop tests results with individuals of similar age and sex.

It is also unclear if athletes from different sports would be expected to achieve similar hop test scores. For example, basketball and soccer are both high-risk sports for ACL injuries. Both sports require quick stops/starts and cutting maneuvers. However, when compared with soccer, basketball requires significantly more jumping and significantly less running. It is unclear whether sport specific demands lead to different hop test scores or if all athletes perform similarly.

Hop tests are typically scored by computing a limb symmetry index (LSI) by comparing the involved lower extremity to the uninvolved. However, there are some concerns regarding the use of the uninvolved limb as the sole standard for the involved limb with any objective testing. The uninvolved

The International Journal of Sports Physical Therapy | Volume 9, Number 5 | October 2014 | Page 597

limb’s abilities may decline during the rehabilitation process and may be affected by prior injury or surgery.29,41 Additionally, an athlete may have perfect limb symmetry and yet be underprepared to compete because both extremities are much weaker or more poorly controlled than the “average” individual.34,41 Unfortunately, with the exception of DeCarlo and Sell’s 1997 study42 of the single hop for distance in high school athletes (average age 14 years, sports unknown), there are no normative data available for hop test performance.20 The purpose of this study was to determine normative values in high school and college basketball and soccer players for four hop tests: the single hop for distance, the triple hop for distance, the crossover hop for distance, and the 6-m timed hop. Two secondary purposes were to assess test-re-test reliability and to assess differences between dominant and non-dominant limbs.

METHODS A total of 372 high school and collegiate (Division I and Division II) student-athletes were included in the study (mean age 17.37 years, range 14-24): 200 soccer players and 172 basketball players comprising eight main groups defined by sex, level of competition, and sport (Table 1). A sample of convenience was recruited from high school and college soccer and basketball leagues. Inclusion criteria for the study were: voluntary participation; signed participant consent or signed parental consent and participant assent; 14 – 25 years of age; member of a competitive soccer or basketball team; and currently participating in practices/games without restriction.

Participants were excluded if they had prior ankle, knee, or hip surgery.

All testing was performed at team facilities by a single examiner. Testing was performed on dry, level, Table 1. Participants age data Female n High school basketball

50

High school soccer

50

Collegiate basketball

35

Collegiate soccer

50

Total

185

n = number, * = Mean in years (range)

Male

Age*

n

15.20 (14,17) 15.00 (14,18) 19.14 (17,22) 19.48 (18,22)

50

17.05 (14,22)

187

50 37 50

Total Samp le Age*

n

15.96 (14,18) 15.58 (14,17) 19.68 (17,23) 19.78 (18,24)

100

17.62 (14, 24)

372

100 72 100

Age* 15.58 (14,18) 15.29 (14,18) 19.42 (17,23) 19.63 (18,24) 17.33 (14,24)

debris-free surfaces, such as a basketball court, weight room floor, or artificial turf. Participants wore athletic shoes of their choosing. Due to the potential for surface irregularities, testing was not performed on grass. Two 15m fiberglass measuring tapes (Champion Sports, Winston-Salem, NC) were fixed to the test surface 15 cm apart. A start line and a 6-meter line were taped to the surface.

Informed consents/assents were obtained prior to testing. Participants were verbally asked about their surgical history. Limb dominance was determined by asking participants which limb they would use to kick a ball for distance.43 All athletes performed at least a 10 minute warm-up of basic lower extremity stretching25 and a general warm-up exercise (e.g. jogging, agility drills, or sport-specific activities). A coin flip determined which limb was tested first.44 Test order was randomized using a Latin square design, which was repeated every four test groups.

Hop tests were conducted according to previously described methods.45 Participants were asked to perform one submaximal trial of the first hop test to familiarize himself/herself with the task.46 Participants then performed three maximal trials that were recorded on one limb followed by the other. The average of the three trials was used for statistical analysis.47 Participants repeated this format for each of the three remaining tests. Distance was recorded to the nearest cm.45 The timed hop was recorded to the nearest hundredth of a second using a stopwatch (NB Coach Digital 30-Lap Chronograph stopwatch, Brighton, MA).45 Participants had approximately 30 seconds rest between trials and approximately one minute rest between tests.48 Because upper extremity movement is a usual component of hop performance, there were no restrictions on arm motion during testing.47,49 To establish reliability, 15 participants were retested 48-72 hours after initial testing.50 The study was approved by the Institutional Review Board of the University of Indianapolis.

Statistical Analysis Data was analyzed using SPSS version 21 for Macintosh. As some of the hop tests in the reliability study were not normally distributed (Shaprio-Wilk p< 0.05), Friedman’s ANOVA was used to determine the differences between day 1 and day 2 scores for

The International Journal of Sports Physical Therapy | Volume 9, Number 5 | October 2014 | Page 598

each leg. The Wilcoxon Signed Rank test, with an α=0.025, was performed to determine within group differences between dominant and nondominant limbs for each of the eight main groups. The Mann Whitney test, with an α=0.0125, was performed to determine main effect differences between sex, level of competition, and sport. In all cases, a Bonferroni adjustment was applied to decrease the risk of a type I error.

Table 3. Male Soccer versus Male Basketball Player Results

RESULTS There were no statistically significant differences between day 1 and day 2 hop test scores, p > 0.05, indicating good test-retest reliability.

Because the Wilcoxon Signed Rank test indicated significant differences between dominant and nondominant limbs for three of the 32 hop tests (Table 2), dominant and non-dominant limb scores were analyzed separately. The Mann Whitney test indicated that males performed significantly better than females, p < 0.0005, for both dominant and nondominant limbs on all four hop tests. This was true overall and for both levels of competition.

The Mann Whitney test indicated that collegiate athletes performed significantly better than high school for both dominant and non-dominant limbs, p < 0.0005, on all four hop tests. This was true for the whole sample and for both sexes. The Mann Whitney test indicated that overall male basketball players performed significantly better than male soccer players on all distance hop tests, α=0.0125 (all ps < .01), but there were no significant differences (dominant limb p=.34, non-dominant limb p=.05) between sports for the two timed hop tests (Table 3). Effect sizes for overall males on the distance hops were small to medium, ranging from d= .38 to d=.66.

Effect sizes for all males on the 6-m timed hop were negligible to small, d=.14 for the dominant limb and Table 2. Statistically Significant Dominant versus Non-dominant Lower Extremity Hop Tests Group

Hop Test

Mean

p-value

Differences

Literature Reported SEM

Single hop*

2.76 cm

p=0.005

4.56 – 7.93 cm

Female college

6-m hop

0.04 sec

p=0.041

0.08 – 0.21 sec

Female college

Triple hop

8.42 cm

p=0.009

15.44 - 23.18 cm

Male high school

SEM = standard error of measurement *= Non-dominant limb superior to dominant limb

d=.29 for the non-dominant limb. For female athletes, the Mann Whitney test indicated no significant differences between basketball and soccer players for all four hop tests at the α= 0.0125 level, with p-values ranging from .28 to .89. Effect sizes for female athletes were negligible to small, d= .02 to d=.20. When examined by level of competition, the Mann Whitney test indicated no significant differences between sports on any hop test at the α= 0.0125 level, p- values ranging from .016 to .134 for high school athletes and .055 to .711 for college athletes. Effect sizes for level of competition were negligible to small, d=.03 to d=.19.

DISCUSSION Significant differences in hop test performance were found between sexes and levels of competition. The differences between sexes and levels of competition were several times greater than the SEM cited in the literature. Therefore, these differences appear functionally relevant with male athletes performing better than female athletes and college athletes performing better than high school athletes for all hop tests.

The findings of differences between sexes are similar to previous studies in which males performed better than females.42,51-55 The consistent differences between sexes across all comparisons are in contrast with two studies. The interaction between age and sex with functional testing noted in these two

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studies36,38 was in younger athletes and specifically examined pre-post pubescent changes, whereas the current study examined a cross-section of two more mature age groups. Therefore, it would be unwise to compare the results of the present study with studies involving pre-pubescent athletes.

The statistically significant differences in hop performance between levels of competition is not surprising given that the athletes who continue beyond the high school level are more likely to have superior skill sets. The differences between high school and collegiate athletes may also be the result of physical maturation. The current findings are consistent with, and expand upon the work of BarberWestin, Noyes, and Galloway,40 who demonstrated that muscle strength increases with age in male and female athletes in a variety of youth sport leagues.

The single hop test results of the current study for high school athletes are slightly greater than those from DeCarlo and Sell’s study.42 This difference may be due to the greater mean age of the high school participants or differences in sport participation within the subjects in the current study.

With regard to sport, basketball is more of a game of jumping and soccer more of a game of running, but both sports require speed and changes of direction.

Intuitively, one would expect basketball players to perform better on the distance hops and for all athletes to perform similarly on the timed hop. However, this was not borne out in the analyses. The results of this study demonstrate an interaction between sport and sex. Female athletes of both sports performed similarly on all hop tests. In contrast, male basketball players performed statistically better on distance hops than soccer players. The mean differences between sports for male athletes were 4.76 cm for the single hop, 25.25 cm for the triple hop, and 19.5 cm for the crossover hop. These differences do not appear to be functionally relevant given the literature SEM (4.56 cm - 7.93 cm for the single hop, 15.44 cm - 23.18 cm for the triple hop, and 15.95 cm - 21.16 cm for the crossover hop). Additionally, these small differences between sports are well within the standard deviations of the proposed normative values, making them clinically irrelevant. While not specifically tracked, several participants were multisport athletes, which may have affected the results.

Table 4. Proposed Normative Values Test

Male College

Female College

Single hop (cm) 6-m timed hop (sec) Triple hop (cm) Crossover hop (cm) Test

192±20 1.74±0.21 632±72 570±75 Male High School

149±17 2.13±0.20 470±53 406±54 Female High School

Single hop (cm)

181±20

129±18

6-m timed hop (sec)

1.91±0.23

2.25±0.24

Triple hop (cm)

583±72

428±54

Crossover hop (cm)

522±77

375±60

At this time, there is not enough evidence to support the use of sport-specific standards for hop tests.

The authors agree that professionals should use caution when purely relying upon limb symmetry for the assessment of hop test performance.20,34 Based on the results of this study, hop test scores should be evaluated based on normative data that are specific to the individual’s sex and level of competition as well as the individual’s limb symmetry index.

Table 4 provides suggested normative data for the subjects of this study for each of the four hop tests.

Normative values were determined by combining dominant and non-dominant data for each group of participants. Statistically significant differences were found between limbs in three of the 32 hop tests (mean differences between limbs were 2.76 cm for male high school single hop, 0.04 sec for female college 6-m timed hop, and 8.42 cm female college triple hop). These differences were not functionally relevant because all were within the SEM noted in the literature46,48,52 (4.56 cm - 7.93 cm for the single hop, 15.44 cm - 23.18 cm for the triple hop, and 0.08 sec to 0.21 sec for the 6-m timed hop) and all were less than the standard deviations of the proposed normative values.

Limitations There are three limitations to this study. Despite the adjusted alpha level, there is the potential for a type I error. Next, while the study included a much larger number of subjects and more well defined groups of athletes than previous studies in the literature, only high school and collegiate soccer and basketball players were included. Therefore, the findings may not be generalizable to broader groups such as recreational athletes, athletes who compete in other sports, or older athletes. Finally, the inclusion of

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individuals with previous non-surgical injuries of the lower extremity may have affected the results of the study. However, it would be highly unlikely that a large study population of high school and collegiate athletes could be found without a prior ankle sprain or other minor injury. The inclusion/exclusion criteria chosen were meant to permit the prototypical athlete to participate in the study, improving the study’s external validity.

There are three key areas for future research on hop tests. First, studies are needed to examine limb symmetry indices within large populations grouped by age, sex, activity level, and prior injury/surgery.

Second studies should strive to determine if sportspecific or position-specific normative values are required. Third, studies are needed to determine if there are any correlations between hop test performance and future lower extremity injuries or athletic prowess (accolades received).

CONCLUSION The results of this study demonstrated differences in hop test performance between sexes and between levels of competition. Therefore, hop test scores should be evaluated as both a comparison with known distance and time standards based on sex and level of competition and relative to an individual athlete’s limb symmetry index.

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11. Myklebust G, Bahr R. Return to play guidelines after anterior cruciate ligament surgery. Br J Sports Med. 2005;39:127-131.

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13. Shelbourne K, Gray T, Haro M. Incidence of subsequent injury to either knee within 5 years after anterior cruciate ligament reconstruction with patellar tendon graft. Am J Sports Med. 2009;37(2):246-251.

14. Kvist J. Rehabilitation following anterior cruciate ligament injury: Current recommendations for sports participation. Sports Med. 2004;34: 269-280.

15. Wright R, Dunn W, Amendola A. Risk of tearing the intact anterior cruciate ligament in the contralateral knee and rupturing the anterior cruciate ligament graft during the first 2 years after anterior cruciate ligament reconstruction: A prospective MOON cohort study. Am J Sports Med. 2007;35:1131-1134.

16. Simoneau G. The challenge of returning to sports for patients post-ACL reconstruction. J Orthop Sports Phys Ther. 2012;42(4):300-301.

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17. Sward P, Kostogiannis I, Roos H. Risk factors for a contralateral anterior cruciate ligament injury.

Knee Surg Sports Traumatol Arthrosc. 2010;18: 277-291.

18. Brophy R, Schmitz L, Wright R, et al. Return to play and future anterior cruciate ligament injury risk after anterior cruciate ligament reconstruction in soccer athletes from the Multicenter Orthopedic Outcomes Network (MOON) Group. Am J Sports Med. 2012;40(10):1-6.

19. Barber-Westin SD, Noyes FR. Factors used to determine return to unrestricted sports activities after anterior cruciate ligament reconstruction.

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21. Lephart S, Perrin D, Fu F, et al. Relationship between selected physical characteristics and functional capacity in the anterior cruciate ligament deficient athlete. J Orthop Sports Phys Ther. 1992;16:174-181.

22. Ross M, Irrgang J, Denegar C, et al. The relationship between participation restrictions and selected clinical measures following anterior cruciate ligament reconstruction. Knee Surg Sports Traumatol Arthrosc. 2002;10(10-19).

23. Sekiya I, Muneta T, Oguichi T, et al. Significance of the single-legged hop test to the anterior cruciate ligament-reconstructed knee in relation to muscle strength and anterior laxity. Am J Sports Med. 1998;26(3):384-389.

24. Gokeler A, Benjaminse A, Hewett T, et al.

Proprioceptive deficits after ACL injury: Are they clinically relevant? Br J Sports Med. 2012;46(3):180.

25. Blackburn J, Morrissey M. The relationship between open and closed kinetic chain strength of the lower limb and jumping performance J Orthop Sports Phys Ther. 1998;27(6):430-435.

26. Thomee R, Neeter C, Gustavsson A, et al. Variability in leg muscle power and hop performance after anterior cruciate ligament reconstruction. Knee Surg Sports Traumatol Arthrosc. 2012;20(6):1143-1151.

27. Jones P, Bampouras T. A comparison of isokinetic and functional methods of assessing bilateral strength imbalance. J Strength Condition Res. 2010;24(6):1553-1559.

28. Jamshidi A, Olyaei G, Heydarian K, et al. Isokinetic and functional parameters in patients following reconstruction of the anterior cruciate ligament.

Isokinetic Exerc Sci. 2005;13(4):267-272.

29. Petschnig R, Baron R, Albrecht M. The relationship between isokinetic strength test and hop tests for distance and one-legged vertical jump test following

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Keskula D, Duncan J, Davis V, et al. Functional outcome measures for knee dysfunction assessment.

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Paterno M, Ford K, Myer G, et al. Limb asymmetries in landing and jumping 2 years following anterior cruciate ligament reconstruction Clin J Sports Med. 2007;17(4):258-262.

Paterno M, Schmitt L, Ford K, et al. Effects of sex on compensatory landing strategies upon return to sport after anterior cruciate ligament reconstruction.

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Soussi S, Wong D, Dellal A, et al. Improving functional performance and muscle power 4-to-6 months after anterior cruciate ligament reconstruction. J Sports Sci Med. 2011;10(4): 655-664.

Chmielewski TL. Asymmetrical lower extremity loading after ACL reconstruction: More than meets the eye. J Orthop Sport Phys Ther. 2011;41(6): 374-374.

Papas E, Carpes F. Lower extremity asymmetry in male and female athletes performing jump-landing tasks. J Science Med Sport. 2012;15:87-92.

36. Quatman C, Ford K, Myer G, Hewett T. Maturation leads to gender differences in landing force and vertical jump performance: A longitudinal study Am J Sports Med. 2006;34(5):806-813.

37. Ford K, Myer GD, Hewett T. Longitudinal effects of maturation on lower extremity joint stiffness in adolescent athletes. Am J Sports Med. 2010;38(9):1829-1837.

38. Ford K, Shapiro R, Myer G, et al. Longitudinal sex differences during landing in knee abduction in young athletes. Med Sci Sports Exerc.

2010;42(10):1923-1931.

39. Ford K, Myer G, Toms H, et al. Gender differences in the kinematics of unanticipated cutting in young adults. Med Sci Sports Exerc. 2005;37(1):124-129.

40. Barber-Westin S, Noyes F, Galloway M. Jump-land characteristics and muscle strength development in young athletes: A gender comparison of 1140 athletes 9 to 17 years of age. Am J Sports Med. 2006;34(3):375-384.

41. Reid A, Birminghamd T, Stratford P, Alcock G, Griffin J. Hop testing provides a reliable and valid outcome measure during rehabilitation after anterior cruciate ligament reconstruction. Phys Ther. 2007;87(3):337349.

42. DeCarlo M, Sell K. Normative data for range of motion and single-leg hop in high school athletes.

J Sport Rehabil. 1997;6:246-255.

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43. Myer G, Schmitt L, Brent J, et al. Utilization of modified NFL combine testing to identify functional deficits in athletes following ACL reconstruction.

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44. Greenberger H, Paterno M. Relationship of knee extensor strength and hopping performance in the assessment of lower extremity function. J Orthop Sports Phys Ther. 1995;22:202-206.

45. Barber S, Noyes F, Mangine R, et al. Rehabilitation after ACL reconstruction: Function testing.

Orthopedics. 1992;15(8):969-974.

46. Booher L, Hench K, Worrell T, et al. Reliability of three single leg hop tests. J Sports Rehabil.

1993;2:165-170.

47. Kramer J, Musca D, Fowler P, et al. Test-retest reliability of the one-leg hop test following ACL reconstruction. Clin J Sport Med. 1992;2: 240-243.

48. Bolgla L, Keskula D. Reliability of lower extremity functional performance tests. J Orthop Sports Phys Ther. 1997;26(3):138-142.

49. Brosky J, Nitz A, Malone T, et al. Intrarater reliability of selected clinical outcome measures following anterior cruciate ligament reconstruction.

J Orthop Sports Phys Ther. 1999;29:39-48.

50. Augustsson J, Thomeé R, Lindén C, et al. Single-leg hop testing following fatiguing exercise: Reliability and biomechanical analysis. Scand J Med Sci Sports.

2006;16(2):111.

51. Gustavsson A, Neeter C, Thomee P, et al. A test battery for evaluating hop performance in patients with an ACL injury and patients who have undergone ACL reconstructions. Knee Surg Sports Traumatol Arthrosc. 2006;14(8):778-788.

52. Munro A, Herrington L. Between session reliability of four hop tests and the agility T-Test. J Strength Condition Res. 2011;25(5):1470-1477.

53. Itoh H, Kurosaka M, Yoshiya S, et al. Evaluation of functional deficits determined by four different hop tests in patients with anterior cruciate ligament deficiency. Knee Surg Sports Traumatol Arthrosc.

1998;6:241-245.

54. Barber S, Noyes F, Mangine R, et al. Quantitative assessment of functional limitations in normal and anterior cruciate ligament-deficient knees. Clin Orthop. 1990;255:204-214.

55. Brumitt J, Heiderscheit B, Manske R, et al. Lower extremity functional tests and risk of injury in Division III collegiate athletes. Int J Sports Phys Ther.

2013;8(3):216-227.

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IJSPT

ORIGINAL RESEARCH

RELATIONSHIPS BETWEEN CORE ENDURANCE, HIP STRENGTH, AND BALANCE IN COLLEGIATE FEMALE ATHLETES Jatin P. Ambegaonkar, PhD, ATC, OT, CSCS1 Lindsey M. Mettinger, MS, ATC1 Shane V. Caswell PhD, ATC1 Andrea Burtt, MS, ATC1 Nelson Cortes, PhD1

ABSTRACT Purpose/Background: Lower extremity injuries such as Anterior Cruciate Ligament (ACL) tears remain a concern in collegiate female athletes. Core endurance and hip strength reportedly influence ACL and lower extremity injury risk. Good neuromuscular control, as measured by the Star Excursion Balance Test (SEBT) test is associated with decreased lower extremity injuries. The exact relationships between core endurance, hip strength, and balance (SEBT scores), and how they impact one another in the female collegiate athlete remain unclear. Thus, the purpose of this study was to investigate relationships between core endurance, hip strength, and balance in collegiate female athletes.

Methods: Forty collegiate female athletes (19.6±1.1yrs, 163.1±7.8cm, 61.3±6.5kgs) performed the SEBT in anterior, posterolateral, and posteromedial directions bilaterally (% leg length), McGill’s anterior, posterior, and left and right plank core endurance tests (seconds), and hip abductor, flexor, extensor, and external rotator isometric strength tests bilaterally (N) using handheld dynamometry. Pearson’s product moment correlations examined relationships between core endurance, hip strength, and balance. A linear regression analysis examined whether core endurance and hip strength influenced balance (p≤0.05).

Results: Anterior SEBT scores were fairly positively correlated with hip flexor and extensor strength. Posterolateral SEBT scores were fairly positively correlated with hip abductor, extensor, and flexor strength (p=0.02-to-0.004; r=0.26-to-0.45).

Fair positive correlations existed between posterior core endurance and hip extensor strength bilaterally (right: p=0.02, r=0.37; left: p=0.003, r=0.47). Core endurance and SEBT scores were not correlated (p>0.05). Core endurance and hip strength did not influence SEBT scores (p=0.47).

Conclusions: Overall, hip strength, but not core endurance was related to SEBT scores in collegiate female athletes. Females with greater hip flexor, extensor, and abductor strength also had better anterior and posterolateral SEBT scores. Having females participate in hip muscle strengthening programs may help improve their SEBT balance scores, as a measure of their neuromuscular control and influence their ACL and lower extremity injury risk.

Level of Evidence: 2b Keywords: Anterior Cruciate Ligament (ACL); lower extremity; Star Excursion Balance Test (SEBT); trunk endurance

1

Sports Medicine Assessment, Research & Testing (SMART) Laboratory, George Mason University, Virginia, USA

CORRESPONDING AUTHOR Jatin P. Ambegaonkar, PhD ATC OT CSCS Sports Medicine Assessment, Research & Testing (SMART) Laboratory George Mason University MS 4E5, Bull Run Hall 10900 University Boulevard Manassas, Virginia, USA, 20110 Phone: 703-993-2123 Fax: 703-993-2025 E-mail: jambegao@gmu.edu

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INTRODUCTION Annually, more than 250,000 Anterior Cruciate Ligament (ACL) knee injuries occur in the United States alone. ACL injury direct surgical costs alone near 850 million dollars annually,1 with an additional 2 billion dollars of indirect costs for post-surgical care and rehabilitation, with many long-term additional sequelae possible (e.g. early-onset knee osteoarthritis).2 Despite clinicians implementing prevention programs,3 ACL injury incidence rates remain high.4 Overall, the ACL injury problem continues to be of great concern to female athletes.5,6 Females have a 3-8 times greater risk for ACL injury than similarly trained males.7 Females are at greater risk for ACL injury than males due to many reasons,7 including non-modifiable (anatomical, hormonal) and modifiable (neuromuscular) risk factors,6,8 especially in sports that require cutting and landing motions, (e.g. lacrosse, basketball).5,9,10 Neuromuscular control of the core8,11 and hip musculature12–14 plays an important role in lower extremity mechanics and may influence ACL and lower extremity injury risk.

The core plays an important role in stabilizing the lower extremity and knee movement during activity.15–17 The core musculature includes the rectus abdominus, transversus abdominis/internal obliques, external obliques, and erector spinae.15–19 During reaction-based tasks (e.g. running, landing) the transversus abdominis/internal obliques are key dynamic stabilizers of the spine, lumbopelvic region, and the whole trunk-pelvis segment, collectively referred to as the ‘core’.17,20–22 The rectus abdominis, external obliques, and erector spinae control trunk position relative to its base of support.17 The transversus abdominis is the first muscle activated during lower body movements.17 In a series of prospective studies examining the effects of core stability on lower extremity injury risk,19,23 Zazulak et al reported that a logistic regression model that included core-specific factors including trunk displacement, low back pain history, and proprioception was able to predict knee ligament injury with 91% sensitivity and 68% specificity. Further, this model predicted knee, ligament, and ACL injury risk in female athletes with 84%, 89% and 91% accuracy, respectively. Overall, previous researchers suggest that core musculature influences lower extremity movement and injury risk during activity.

Zazulak et al noted decreased hip muscle (specifically gluteus maximus) activity in females than males during landing and suggested that it may be an important factor in the increased susceptibility of female athletes to ACL injuries.24 Researchers have also found that individuals with greater hip abduction strength had lesser knee valgus motion during single leg squats, 12 and individuals with greater hip external rotation strength had lower vertical ground reaction forces and external knee adduction and flexor moments during landing,14 all of which are potentially harmful to the ACL. Stearns and Powers found that when recreationally active women participated in a hip-focused training program, the participants’ lower knee/hip extensor moment ratios and lower knee adductor moments were positively affected, and their lower extremity mechanics changed in a manner consistent with decreased ACL injury risk during a drop-jump task.25 Deficits in neuromuscular postural stability or balance tests have also been suggested to increase lower extremity injury risk.26,27 The terms postural stability and balance are often used interchangeably but may describe different constructs. In this study, balance was operationalized as the ability to maintain postural stability (standing on one leg) while performing a reach with the other leg (reaching as far as possible with the other leg in a specified direction without losing support) as described in performance of the Star Excursion Balance Test (SEBT).28,29 Poor SEBT performance has been noted to predict increased lower extremity injury risk on multiple sports.27,30,31 Plisky et al31 also found that female athletes with lower SEBT balance reach distances (less than 94% of leg length) were 6.5 times more likely to have a lower extremity injury than athletes with higher reach distances.

Overall, increased core endurance, greater hip muscle strength, and better performance on the SEBT have been reported to be associated with reduced ACL and lower extremity injury risk.8,15,17,19,23,32 Still, the exact interrelationships among these factors remain unclear. The purpose of this study was to investigate relationships among core endurance, hip strength and balance performance on the SEBT. A secondary purpose was to determine if core endurance and hip strength influenced SEBT performance.

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METHODS Participants Forty collegiate female athletes (19.6±1.1 years, 163.1±7.8 cm, 61.3±6.5 kg) recruited from a universities’ lacrosse and soccer teams participated in the study. Participants were excluded if they had a lower extremity injury or any neurological or musculoskeletal condition affecting their mobility or balance or were not otherwise healthy at the time of testing.

Procedures The local Institutional Review Board approved all testing procedures. All participants signed an informed consent form prior to participation. All testing was performed in a single session in a controlled research laboratory. The same investigators measured the same tasks throughout the study. The following were the outcome measures for the study: Star Excursion Balance Test (Lower Quarter) Lower quarter balance was measured using the SEBT.31 The SEBT uses a single-leg stance and requires participants to perform a maximal reach of the opposite leg along marked lines while keeping the stance leg placed stable at the center, and then return to the initial upright posture without losing balance.28,29

The SEBT was performed based on previously published methods.31,33,34 Specifically, participants performed the SEBT in three reach directions: anterior (SEBTANT-Figure 1A), posterolateral (SEBTPL-Figure 1B), posteromedial (SEBTPM-Figure 1C). All participants were taught how to perform the test by the same investigator using both verbal instruction and demonstration. Participants were allowed 3 practice trials in each direction before actual test performance.

All participants performed reaches first on the right leg and then the left leg. The direction of reaches was in the following order: anterior, posteromedial, and finally posterolateral. Participants had 15-second rest intervals between each trial on the same leg and the same direction and a 1-minute rest interval between reaches in the different directions and when changing feet. So an exemplar trial order and rest period interval was as follows: right leg anterior trial 1 – 15-second rest interval – right leg anterior trial 2 – 15-second rest interval – right leg anterior trial 3 – 1-minute rest interval (switching directions); then right leg posteromedial trial 1 – 15-second rest interval – right leg posteromedial trial 2, and so on.

A trial was disregarded and repeated if: (1) the participant was unable to maintain single leg stance, (2)

Figure 1. Star Excursion Balance Test (SEBT) Directions; 1A – Anterior Reach Direction; 1B – Posterolateral Reach Direction; 1C – Posteromedial Reach Direction.

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the heel of the stance foot did not remain in contact with the floor, (3) weight was shifted onto reach foot, or (4) the participant did not maintain start and return positions for one full second.

Reach distances for each direction’s three trials were averaged and normalized to limb length (%LL, cm) which was measured from the anterior superior iliac spine to the medial malleolus bilaterally.29 Overall, 6 different SEBT scores were calculated: 3 directional scores on the right (-R) leg (SEBTANT-R, SEBTPL-R, and SEBTPM-R) and 3 directional scores on the left (L) leg (SEBTANT-L, SEBTPL-L, and SEBTPM-L). Finally, all of these 6 SEBT were averaged to result in a single composite SEBT score per participant (SEBTCOM).

McGill’s Core Endurance Tests McGill’s tests were used to examine participants’ core endurance. These tests consisted of four positions: the trunk anterior flexor test, the right and left lateral plank, and trunk posterior extensor test.35 Participants performed one practice trial that lasted a few seconds to confirm position and then one actual test trial was recorded per position where the

maximum time (seconds) participants could hold a static position was measured. The same investigator visually determined the end of all tests. This investigator verbally used the word ‘start’ and ‘stop’ to inform the participant to begin and end the test while an assistant investigator recorded the times using a stopwatch, except in the trunk posterior extensor test where the assistant held straps to stabilize the lower body and the investigator determined the start and end of the test.

For the trunk anterior flexor test, participants sat with their backs flat against a wooden wedge angled at 60o with hands across their chest and their knees both flexed to a 90-degree angle as determined by a goiniometer (Figure 2A). Time recording started when the wedge was moved back 10 cm (Figure 2B), and stopped when the trunk deviated either forward or backward from the 60o angle.

For the left lateral musculature plank test, participants’ feet were placed one on top of the other, the right arm was perpendicular to the floor, elbow resting on the mat, with the left arm across the chest

Figure 2. McGill’s Core Endurance Tests; 2A – McGill’s Anterior Trunk Flexor Test, Starting Position; 2B – McGill’s Anterior Trunk Flexor Test, Testing Position; 2C – McGill’s Left Lateral Musculature Plank Test; 2D – McGill’s Right Lateral Musculature Plank Test; 2E – McGill’s Posterior Trunk Extensor Test.

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and the left hand on the right shoulder (Figure 2C).

A similar position for the right lateral musculature plank test, but with the left arm perpendicular to the floor (Figure 2D). Time was stopped when the investigator visually determined that the line between the participants’ trunk or lower body segments (thigh or shank) was not maintained.

For the trunk posterior extensor test, participants lay prone on an examination table with both their ASIS’s on the edge of the table, their hands on the seat of a chair placed in front of them at the edge of the table.

An assistant held straps above and below their knees to secure participants’ lower body (Figure 2E). Time was started when participants assumed a horizontal position of the trunk, removing their hands off of the chair and crossed them across their chest, and stopped when participants were unable to remain in that position.

Isometric Hip Strength Isometric hip strength (of the hip abductors (ABD), flexors (FL), external rotators (ER) and extensors (EXT)) was measured bilaterally using a handheld dynamometer using a make test (Muscle Commander, J-Tech Medical Inc. Midvale, Utah, USA). The handheld dynamometer has been shown to be a reliable instrument for measuring isometric hip extension strength.36–38 The same investigator gave verbal encouragement to each participant while the assistant examined the computer screen to ensure that the strength scores were being recorded by the dynamometer system.

The testing protocol and positions were based on manufacturer recommendations and previously published reliable manual muscle testing positions.37,38 All testing was performed first on the left then the right leg with a 10-second rest period after each of four trials, per manufacturer recommendations. Each testing trial was maintained for four seconds. Four trials were performed for each muscle group with the first trial being a practice trial, and the other three trial scores averaged for analyses (N).

For the hip abductors (Figure 3A), participants lay on their left or right side with their knees and hips flexed to 45° on the examination table. No other pelvic stabilization was provided. The investigator placed resistance on the lateral aspect of the distal femur as the participants tried to move their hip into

abduction against the investigator’s isomeric manual resistance using a make test.

For the hip flexors, participants sat on the edge of the examination table with their legs hanging and their hands holding the sides for the table (Figure 3B). The investigator placed resistance on the anterior aspect of the distal femur as the participants tried to flex their hip against the investigator’s isomeric manual resistance.

For the hip external rotators, participants sat on the table with their hands holding the side and a towel between their thighs (Figure 3C). The investigator placed resistance on the medial surface of the distal tibia as the participants tried to externally rotate their hip and move their foot towards the other leg against the investigator’s isomeric manual resistance.

For the hip extensors, participants lay prone with their hips off the table and feet on the ground (Figure 3D) with the test knee flexed to 90 degrees and the hip relaxed. The investigator applied resistance to the posterior mid portion of the femur as participants tried to extend their hip towards the ceiling against the investigator’s isomeric manual resistance.

Statistical Analyses Pearson’s product moment correlations were used to examine relationships between core endurance tests, measures of isometric hip strength, and SEBT reaches. A linear regression analysis with core endurance and hip strength variables as predictors entered simultaneously was used to examine whether these variables predicted SEBT scores. All data were examined with the PASW 19.0 software (IBM Corp, Armonk, NY). An apriori alpha level of 0.05 was used for all tests. The strength of the relationships was described as detailed by Portney and Watkins, where 0.00-0.25 = little or no relationship; 0.26-0.50 = fair degree of relationship; 0.51-0.75 = moderate to good relationship, and 0.76-1.00 = good to excellent relationship.39 RESULTS Balance and Hip Strength All SEBT, McGill’s and hip strength descriptive statistics (means and standard deviations) are presented in Table 1.

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Figure 3. Hip Muscle Strength Tests; 3A – Hip Abductors; 3B – Hip Flexors; 3C – Hip External Rotators; 3D – Hip Extensors.

SEBT combined scores (SEBTCOM) were fairly positively correlated with HABD-R (r=0.34, p=.03), HFL-L (r=0.38, p=.02), HEXT-R (r=0.38, p=.01), and HEXT(r=0.34, p=.03) (Table 2). Right anterior SEBT L scores (SEBTANT-R) were fairly positively correlated with hip flexor and extensor strength bilaterally: HFL-R (r=0.43, p=.005), HFL-L (r=0.44, p=.005), HEXT(r=0.42, p=.007), and HEXT-L (r=0.34, p=.03). Left R anterior SEBT scores (SEBTANT-L) were fairly positively correlated with hip flexors strength bilaterally: HFL-R (r=0.36, p=.02) and HFL-L (r=0.37, p=.02) (Table 2).

Right posterolateral SEBT scores (SEBTPL-R) were fairly positively correlated with right hip abductor and extensor strength: HABD-R (r=0.44, p=.005) and HEXT-R (r=0.33, p=.004) (Table 2). Left posterolateral

SEBT reach scores (SEBTPL-L) were fairly positively correlated with right hip abductor (HABD-R) (r=0.38, p=.02) and left hip flexor (HFL-L) (r=0.32, p=.005) strength.

Bilateral posteromedial SEBT reach scores (SEBTPM-R and SEBTPM-L) were not correlated with any of the hip strength scores (Table 2; p≤0.05).

Balance and Core Endurance Participants’ right posteromedial SEBT reach scores on the right leg (SEBTPM-R) were fairly positively correlated with left lateral McGill’s test scores (r=.32; p=.04) (Table 3). No other significant correlations were found between SEBT scores and McGill’s test scores (p≤0.05) (Table 3).

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Table 1. Star Excursion Balance Test (SEBT) Scores (% leg length), McGill Test Scores (s), and Hip Strength (N) (Means + SD)

Test

Side

Direction

M

SD

Anterior Posteromedial Posterolateral

68.69 107.45 106.18

±6.41 ±10.34 ±10.19

Anterior Posteromedial Posterolateral

68.48 111.67 103.06

±6.46 ±1 0 . 3 2 ±10.07

87.97

±6.49

Trunk flexor Trunk extensor Right lateral Left lateral

57.12 71.00 36.51 36.85

±37.64 ±26.30 ±13.82 ±14.49

Abduction Flexion Extension E x te r n a l Ro t a t i o n

27.23 26.24 14.18 26.4 1

±3.22 ±3.50 ±2.26 ±4 .73

Abduction Flexion Extension E x te r n a l Ro t a t i o n

26.59 26.27 13.11 26.5 0

±3.55 ±3.20 ±1.75 ±4 .73

SEBT Right

Left

Overall SEBT Composite Score (SEBTCOM) McGill’s Tests

Hip Strength

Right

Left

Core Endurance and Hip Strength Participants’ posterior McGill’s (trunk extensor) test scores were fairly positively correlated with their hip extensor strength bilaterally HEXT-R (r=.47; p=.003) and HEXT-L (r=.37; p=.02) (Table 4). No other significant correlations were found between McGill’s and hip strength test scores (Table 4; p≤0.05).

Regression Analyses McGill’s test and hip strength scores did not influence SEBT scores (p=.47).

DISCUSSION The primary findings of this study include significant positive relationships between: 1) anterior balance and hip flexor and extensor strength; 2) posterolateral balance and hip abductor, extensor, and flexor strength, and 3) posterior core endurance and hip extensor strength bilaterally. Hip strength and core endurance did not influence SEBT balance scores.

Balance and Hip Strength In this study, isometric hip abductor, flexor, external rotator, and extensor muscle strength were measured because these muscle have been shown to be active during the SEBT directional reaches.32 While muscle activation does not directly indicate muscle strength, the two measures are associated.29 Isometric strength measure of the flexors, extensors, and abductors demonstrated positive correlations with SEBT scores. Generally, individuals who had greater hip strength scores also had overall better SEBT scores. Previous researchers have noted that female basketball players with worse SEBT composite scores (less than 94% of their limb length) were 6.5 more times more likely to have a lower extremity injury than those with higher SEBT scores.31 Rasool et al demonstrated that SEBT scores could improve between 11-36% after 2-4 weeks of neuromuscular balance training.40 Hip strengthening exercises have been noted to improve sagittal plane dynamic balance (anterior reach on the Y-balance test) three

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Table 2. Pearson Correlations among Hip Abduction (ABD-R, -L), Flexion (FL-R, -L), External Rotation (ER-R, -L), and Extension (EXT-R, -L) strength (N) for the Right and Left legs and Star Excursion Balance Test (SEBT) (% Leg Length) scores in the Anterior (ANT-R, -L), Posterolateral (PL-R, -L), Posteromedial (PM-R, -L), Right Leg Combined (COM-R), Left Leg Combined (COM-L), and Both Legs Combined (COM) HABD-R

HABD-L

HFL-R

HFL-L

HER-R

HER-L

HEXT-R

HEXT-L

SEBTANT-R

r p

.21 .21

.14 .41

.43 .005*

.44 .005*

.22 .18

.33 .04*

.42 .007*

.34 .03*

SEBTANT-L

r p

.20 .23

.18 .28

.36 .02*

.37 .02*

.24 .15

.25 .11

.25 .12

.26 .10

SEBTPL-R

r p

.44 .005*

.30 .07

.17 .30

.30 .06

.20 .22

.19 .24

.33 .04*

.27 .09

SEBTPL-L

r p

.38 .02*

.22 .18

.20 .22

.32 .05*

.13 .43

.18 .28

.26 .10

.30 .07

SEBTPM-R

r p

.19 .24

.03 .86

-.04 .79

.14 .41

.27 .10

.22 .17

.31 .05

.20 .23

SEBTPM-L

r p

.11 .52

-.05 .76

.01 .95

.10 .53

.02 .91

.14 .38

.29 .07

.16 .32

SEBTCOM-R

r

.38

.27

.37

.45

.27

.31

.41

.36

p

.02*

.10

.01*

.004*

.10

.05*

.008*

.02*

r

.29

.14

.21

.31

.14

.22

.33

.29

p

.07

.41

.20

.06

.40

.16

.04*

.07

r

.34

.21

.29

.38

.20

.27

.38

.34

p

.03*

.21

.07

.02*

.21

.09

.01*

.03*

SEBTCOM-L

SEBTCOM

Table 3. Pearson Correlations among McGillâ&#x20AC;&#x2122;s Test scores (s) in the Trunk Flexor, Trunk Extensor, Right Lateral, and Left Lateral directions for the Right (-R) and Left (-L) legs and Star Excursion Balance Test (SEBT) scores (% Leg Length) in the anterior (ANT-R, -L), posterolateral (PL-R, -L), posteromedial (PM-R, -L) directions for the right and left legs McGillâ&#x20AC;&#x2122;s Test

SEBTANT-R SEBTPL-R SEBTPM-R SEBTANT-L

Trunk Flexor

Trunk Extensor

Right Lateral

Left Lateral

r

.02

.06

-.22

-.11

p

.90

.69

.17

.49

r

.17

.17

.17

.12

p

.29

.30

.31

.47

r

.11

.18

.26

.32

p

.51

.28

.10

.04*

r

.03

-.09

-.27

-.23

p

.88

.60

.09

.15

SEBTPL-L

r p

.02 .93

.20 .22

.13 .42

.12 .45

SEBTPM-L

r

.18

.23

.15

.24

p

.27

.16

.36

.13

months post ACL reconstruction as compared to traditional rehabilitation.41 Similarly, Filipa et al found that a lower extremity strengthening and core stability program increased SEBT scores in soccer players.34 When combined with prior work, the current findings of greater hip strength being associated with better SEBT performance are important for clinicians to consider as they can use this information to encourage female athletes to participate in hip strengthening and balance training programs.

In the anterior direction, SEBT scores were positively correlated with hip flexion strength bilaterally. This finding suggests that when the hip flexors (e.g. the quadriceps) are stronger, an individual can reach farther in the anterior direction. In support, Earl et al. found that both vastus medialis, and vastus medialis obliquus activation (both components of the quadriceps muscles) was greater in anterior

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Table 4. Pearson Correlations among Hip abduction (ABD-R, -L), flexion (FL-R, -L), external rotation (ER-R, -L), and extension (EXT-R, -L) Strength (N) for the Right and left Legs and McGill’s Test (s) in the Trunk Flexor, Trunk Extensor, Right Lateral, and Left Lateral directions

McGill’s Test

HABD-R HFL-R HER-R HEXT-R HABD-L HFL-L HER-L HEXT-L

Trunk Flexor

Trunk Extensor

Right Lateral

Left Lateral

r

-.01

.07

.26

.16

p

.93

.69

.11

.32

r

-.001

.06

-.05

-.06

p

.99

.71

.74

.70

r

.11

-.12

.12

.08

p

.48

.45

.46

.61

r

-.07

.47

.29

.20

p

.68

.003*

.07

.21

r

.02

.03

.21

.10

p

.92

.83

.19

.52

r

.10

.02

-.05

-.01

p

.56

.92

.78

.95

r p r

.17 .30 -.13

-.16 .32 .37

.004 .98 .28

.05 .75 .20

p

.41

.02*

.08

.23

* Significant Correlations at p < 0.05 excursions in other SEBT directions.32 While both these quadriceps muscle components do not cross the hip joint themselves, the authors are reasonably confident that these muscle activations reflect overall quadriceps muscle activity patterns during SEBT anterior reaches.

SEBT anterior scores were also fairly positively correlated bilaterally with hip extension strength.

This finding may suggest that the hip extensors are important and required to control the pelvis and trunk during anterior reaches while maintaining balance. SEBT right anterior scores were also fairly positively correlated with left hip external rotator muscle strength but not right hip external rotator muscle strength. This observation may relate to the fair degree of the relationships i.e. as the motion in the anterior reach is primarily in the sagittal plan,

the external rotators may not be as influential in this direction. Still, the lack of consistent relationships between anterior directional reaches and hip external rotator and abductor strength should be examined using muscle measurement techniques including electromyography. Overall, several SEBT scores were positively correlated with multiple hip muscle strength measures, suggesting that examining the anterior reach may provide a general measure of hip muscle strength and vice versa.

Right posterolateral SEBT reach scores were positively correlated with right leg hip abductor and extensor strength, and left posterolateral SEBT reach scores were positively correlated with right hip abductor and left hip flexor strength. These findings were not consistently observed in all muscles, and may be a reflection of the moderate ‘fair’ strength of

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the correlations between posterolateral reaches and hip strength. Still, these findings generally suggest that individuals with stronger hip abductors, flexors and extensors may be able to reach farther backwards and laterally without losing balance. Such movements are frequently performed in sports that require the individual to backpedal (e.g. basketball or lacrosse or soccer player defending the net or goals respectively). Therefore, posterolateral SEBT scores may also be a good general measure of hip muscle strength and can be used by clinicians to examine athletesâ&#x20AC;&#x2122; functional performance and progress during training and rehabilitation.

Interestingly, posteromedial SEBT reach scores not correlated (either lower extremity) with hip strength scores. Norris et al42 found that hip muscle activation in the SEBT posteromedial direction was lowest as compared to the anterior and medial directions.

Combining these prior reports with the current findings of no correlations of the posteromedial direction (crossing over backwards) with hip strength suggest that this motion may not be as clinically important to examine as a measure of hip and lower extremity function as compared to the other directions.

Balance and Core Endurance Fair positive correlations existed between left lateral core endurance and right posteromedial SEBT scores but not in other directions consistently. The authors are unsure of this finding as the core should be active bilaterally during dynamic lower extremity movements Still, from the limited correlations observed, it appears that that include lateral core musculature training programs could potentially improve posteromedial direction balance.

No other correlations existed between core endurance and balance. Similarly, Gordon et al also did not find any relationships among core endurance (as measured by the Bent Knee Lowering test) and balance (as measured by the SEBT).29 Shirley et al43 examined core muscle activation during single leg squats and reported that participants who voluntarily activated their core musculature had improved frontal plane hip and knee kinematics than those who did not activate their core.43 The discrepancy between these prior studies and the current findings may be due to the differing tasks. Overall, when

combining prior findings with the findings of the current study, it appears that further investigations are needed to clearly determine if core musculature endurance and SEBT performance are related to each other.

Core Endurance and Hip Strength Core extensor endurance was positively correlated with hip extensor strength. Most of the prime mover muscles for the lower extremity (e.g. the hamstrings, quadriceps, and iliopsoas muscles) attach in the similar anatomical areas as the core musculature (e.g. the ilium, ischium and pubic bones) leading clinicians to believe that the hip extensors and posterior hip muscles influence the lower back.

Inconsistent relationships existed between hip external rotation measures and lower SEBT scores.

In support, Gordon et al who also measured balance using the SEBT did not find significant relationships between hip external rotation strength and these scores.29 Gordon attributed this to muscles other than the external rotators being involved in complex construct of balance.29 Therefore, the hip flexors, extensors, abductors, and external rotators were examined in the current study in order to try to assess additional hip muscles. While positive relationships were noted among the hip flexors, extensors, and abductors and SEBT scores, these hip muscles were only measured during an isometric motion and not during a dynamic activity. Future researchers may use dynamic hip strength tests (e.g. isotonic or isokinetic testing) to measure hip musculature and their relationship to measures of balance.

Limitations and Recommendations The relatively small sample size and age range decreases the generalizability of this study to the general population. Still, to the authorsâ&#x20AC;&#x2122; knowledge, this study is the first combined examination of core endurance, hip muscle strength, and SEBT balance performance as a measure of neuromuscular control in collegiate female lacrosse and soccer players. Further, although the handheld dynamometer instrument has been shown to be reliable and we used manufacturer instructions for all tests, future investigators could use more stable positioning (e.g. straps for stabilizing the investigator, straps for stabilizing pelvis during hip rotation) when performing

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isometric testing. In addition, while McGill’s tests in four directions were used to assess the endurance of the prime movers of the core, other muscles may have contributed to McGill’s test scores (e.g. shoulder muscles to support the body in planks). Thus, future researchers should consider other tests to isolate core muscles. The same test order was used for all participants. While adequate rest intervals were given to participants between repetitions of tests to mitigate the role of fatigue, whether there was a systematic order effect for the SEBT should be examined in the future. Also, in addition to the hip muscles, the knee and various other lower leg muscles are involved in balance,32 and their roles in maintaining balance need further examination.

Clinical Implications A couple of important clinical implications of this study are the observations that (1) hip strength is associated with SEBT performance and (2) greater hip muscle strength is related to better performance on the SEBT in multiple directions. Prior researchers note that most lower extremity muscles are activated during the SEBT,32,42 and that a hip-focused training program can decrease ACL injury risk factors.25 Combining these prior reports with the current observations, it appears that clinicians can use the SEBT to monitor patient progress and guide clinical decisionmaking if they are using hip strengthening as part of their training or rehabilitation programs.42 Conclusions Overall, the study findings suggest that some hip strength measures, but not core endurance, is related to SEBT scores in collegiate female athletes.

Specifically, greater hip flexor, extensor, and abductor strength were related to better anterior and posterolateral SEBT scores. Since prior work suggests that SEBT balance improves after training programs, and that better SEBT performance is associated with reduced lower extremity injury risk, clinicians should encourage female athletes to participate in hip muscle strength training programs.

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43. Shirey M, Hurlbutt M, Johansen N, King GW, Wilkinson SG, Hoover DL. The inďŹ&#x201A;uence of core musculature engagement on hip and knee kinematics in women during a single leg squat. Int. J. Sports Phys. Ther. 2012;7(1):1-12.

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IJSPT

ORIGINAL RESEARCH

SIDESTEP AND CROSSOVER LOWER LIMB KINEMATICS DURING A PROLONGED SPORT-LIKE AGILITY TEST Danielle Potter, SPT, MS1,2 Kellie Reidinger, SPT, MS2 Rebecca Szymialowicz, SPT, MS2 Thomas Martin, PhD3 Donald Dione, MS4 Richard Feinn, PhD5 David Wallace, PT, PhD6 Juan C. Garbalosa, PT, PhD7

ABSTRACT Background: Non-contact anterior cruciate ligament (ACL) injuries in athletes occur more often towards the end of athletic competitions. However, the exact mechanisms of how prolonged activity increases the risk for ACL injuries are not clear.

Purpose: To determine the effect of prolonged activity on the hip and knee kinematics observed during self-selected cutting maneuvers performed in a timed agility test.

Methods: Nineteen female Division I collegiate soccer players completed a self-selected cutting agility test until they were unable to meet a set performance time (one standard deviation of the average baseline trial). Using the 3D dimensional coordinate data the cut type was identified by the principle investigators. The 3D hip and knee angles at 32ms post heel strike were analyzed using a two-factor, linear mixed model to assess the effect of prolonged activity and cut type on the recorded mean hip and knee angles.

Results: Athletes performed either sidestep or crossover cuts. An effect of cut type and prolonged activity was seen at the hip and knee. During the prolonged activity trials, the knee was relatively more adducted and both the hip and knee were less flexed than during the baseline trials regardless of cut type. Regardless of activity status, during sidestep cuts, the hip was more internally rotated and abducted, and less flexed than during crossover cuts while the knee was more abducted and less flexed during the sidestep than crossover cuts.

Conclusions: During a sport-like agility test, prolonged activity appears to predispose the athlete to position their knee in a more extended and abducted posture and their hip in a more extended posture. This position has been suggested to place stress on the ACL and potentially increase the risk for injury. Clinicians may want to consider the effects of prolonged activity on biomechanical risk factors for sustaining ACL injuries in the design of intervention strategies to prevent ACL injuries .

Key Words: ACL injury, cutting, motion, knee Level of Evidence: Level 4

1

Graduate Assistant, Motion Analysis Laboratory, Quinnipiac University, Hamden, CT, USA 2 Student, Department of Physical Therapy Quinnipiac University, Hamden, CT, USA 3 Assistant Professor, Department of Biomedical Sciences, Quinnipiac University, Hamden, CT, USA 4 Research Associate II, Yale University, School of Medicine, New Haven, CT, USA 5 Assistant Professor, Frank H Netter, MD, School of Medicine, Quinnipiac University, Hamden, CT, USA 6 Associate Professor, Department of Physical Therapy, Quinnipiac University, Hamden, CT, USA 7 Director, Motion Analysis Laboratory, Clinical Associate Professor, Physical Therapy Department, Quinnipiac University, Hamden, CT, USA Study was approved by the Quinnipiac University, Human Experimentation Committee, HEC #3411 ConďŹ&#x201A;icts of Interest and Source Funding: None were declared by any author.

CORRESPONDING AUTHOR Juan C. Garbalosa, PT, PhD Quinnipiac University MNH 141A 275 Mount Carmel Ave Hamden, CT 06518 OfďŹ ce: 1.202.582.8552 Fax: 1.203,582.8706 E-mail: juan.garbalosa@quinnipiac.edu

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INTRODUCTION Anterior cruciate ligament (ACL) injuries are one of the most common injuries that occur in competitive sports.1,2 Greater than seventy percent of all ACL ruptures are caused by non-contact mechanisms, meaning that there is no external force causing the injury.2-9 A high incidence of these injuries are sports related, affecting female athletes two to ten times more frequently than males, incurring significant economic costs.3,4,8-13 Both the long-term physical consequences and high economic costs of ACL injuries point to the importance of achieving a better understanding of the mechanism of injury and development of effective preventive programs.

While there are many factors associated with the increased risk of females sustaining an ACL injury two potentially modifiable risk factors are lower limb biomechanics and fatigue.2,6,12,14-16 Athletes are placed at higher risk for non-contact ACL injury when performing a sudden change in direction and may be at an even greater risk when muscle fatigue is involved during the maneuver.17-19 Non-contact injuries most commonly occur during landing, pivoting (at or near full knee extension), deceleration, and change of direction maneuvers during play.3,8,9,12 Through the observation of ACL injury mechanisms in basketball players, Ireland et al have described the position in which the ACL is at the greatest risk of rupture: the hip positioned in adduction, internal rotation, and decreased flexion, and the knee positioned in valgus, external rotation, and decreased flexion.8,9,13 Different cutting maneuvers have been shown to place the lower limb at varying levels of risk for sustaining an ACL injury.4,20 In particular, a sidestep cut appears to put the athlete at the greatest risk of injury.5,21 Cochrane et al21 defined sidestep cuts as accelerating toward the direction opposite of the planted leg (Figures 1a, 1b). In contrast, a crossover cut is defined as crossing one leg over the planted leg and accelerating in the same direction of the push off leg (Figures 1c 1d).

Prolonged activity may alter lower limb biomechanics, cutting strategies, and the ability of an individual to maintain trunk control.17-19,22-26 Furthermore, prolonged activity can affect joint proprioception and neuromuscular responses, thereby decreasing

the ability to sense joint position and diminishing the protective roles of muscles.27,28 Due to these factors the ability to maintain motor control, when planning for precision movements, such as cutting, may be impaired, possibly leading to a decrease in dynamic joint stability and failure to prevent the joint from going into a high-risk injury posture.27 The inability to maintain muscular control may explain why injury rates tend to increase as athletes fatigue during games.29-32 Furthermore, studies that have focused on biomechanics during prolonged activity have used scenarios that do not mimic game-like environments.18,26,29,33 Therefore, to fully understand the effect of prolonged activity and its impact on the risk for ACL injury, the use of testing protocols that simulate a game-like environment should be considered.

Using an agility test, the authors of this study have developed a paradigm that allows athletes to perform self-selected cut types under different conditions. This paradigm allows for an evaluation of lower limb biomechanics during a repetitive activity that mimics the physical demands of competition. Therefore, the purpose of this study was to determine the effect of prolonged activity on the kinematics of the hip and knee while the subjects performed a self-selected cutting maneuver during a timed agility test that closely mirrors the demands of soccer. Prolonged activity was hypothesized to have a significant effect on the kinematics of the hip and knee during a timed agility test, and these prolonged activity-related changes could put athletes in a more at-risk position for a non-contact ACL injury.

METHODS Subjects Twenty-one female NCAA, Division I collegiate soccer players were recruited to participate in this study. Of the 21 subjects, 19 completed the study.

Two subjects did not complete the study due to sustained injuries unrelated to the study. The subject demographics of the 19 who completed the study are presented in Table 1. To be included in this study, subjects had to be members of the womenâ&#x20AC;&#x2122;s Quinnipiac University soccer team, free of injury at the time of enrollment in the study, and for at least 1 year prior to commencement of the study, and not

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Figure 1. The two types of cuts self-selected by the athletes during the performance of the agility test. 1a and 1b show the Sidestep cut, and 1c and 1d show the Crossover cut.

have any musculoskeletal, cardiovascular, or neuromuscular condition that was contraindicated for participation in this study. Subjects were excluded from the study if they did not meet these inclusion

criteria. Eight subjects had a prior history of lower extremity injury prior to the study, reported in Table 1. All experimental procedures were approved by Quinnipiac Universityâ&#x20AC;&#x2122;s Institutional Review Board.

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Table 1. Select demographics of the subjects who completed the study (n = 19) and mean number of trials required to complete the agility test protocol.

Characteristic

M e an ± SD

Mean Age, years (± 1 S.D.)

19.4 ± 1.3

Mean Height, cm (± 1 S.D.)

164.3 ± 5.6

Mean Mass, kg (± 1 S.D.)

62.2 ± 7.0

Number of subjects with prior history of lower extremity injury*

8

Mean number of agility trials completed by subjects

20.6 ± 9.4

*1 subject-bilateral ACL tears and reconstruction, 1 subject-medial collateral ligament tear, 1 subject-meniscal tear, 3 subjects-tibial or fibular fracture, 2 subjects-multiple lower extremity injuries.

Procedures Data collection occurred over two sessions, approximately one week apart for each subject. At the first session, informed consent was obtained after which demographic and anthropometric data consisting of age, height, weight, and previous lower extremity injury history were recorded. At the first session an agility test training session was then provided for each subject. At the second data collection session the agility testing protocol consisted of having the subject complete a modified T-Test, repetitively. The T-Test required the subject to run through a T-shaped obstacle course (Figure 2) as fast as possible utilizing a self-selected cut type. The modified T-Test has been shown to be a reliable measure of agility but has not been utilized to simulate sport during

Figure 2. Overhead view of the agility test with the subject starting on the left. The arrows depict the path the subject took. The dark grey arrow represents the first turn analyzed and the light grey arrow represents the second turn analyzed in this study for each trial.

biomechanical analysis.34 The training session consisted of an explanation of the agility test protocol, a demonstration of the protocol and an opportunity to run through the obstacle course performing both left as well as right cuts. During this practice session, the subjects were instructed to run through the course, each time through increasing their speed, until they were running at their maximum speed. On average the subjects performed 4 practice runs from each side through the course.

At the second data collection subjects warmed up for 10 minutes while jogging on a treadmill at a selfselected pace. After completing the warm-up, a full body Cleveland Clinic marker set (Figure 3) was applied to the subjects using double-sided adhesive tape. Once all the markers were in place, the subjects were asked to stand still in the middle of the data collection volume with their feet approximately 10 inches apart. The subjects then completed the agility test protocol running at maximum speed for all trials, while video data was recorded using a 10 camera 3-dimensional motion analysis system (Motion Analysis Corporation, Santa Barbara, CA) sampling at a frequency of 240 Hz. A timed based decrement in performance model was used to determine the endpoint of the agility test protocol. For the first four trials, the subject had a 60 second rest period between each run. The time for these runs were recorded and averaged and were considered to be the baseline trials. The subject then continued to perform the agility test, continuing to run at maximum speed, while alternating from all left turns and all right turns beginning every 30 seconds (includes rest as well as trial, Figure 2). The subject continued the test until they failed to have two consecutive runs within one standard deviation of the established average baseline time for the trials. The subject was then asked to perform two more runs, one from each side, during which video data was recorded. These last two trials were considered the prolonged activity trials. The average number trials of (± 1 S.D.) to complete the test protocol are reported in Table 1. The subject’s time to complete the obstacle course was recorded using a timing gait device (Equine Electronics Timing System, Equine Electronics).

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Data Analysis The X, Y, Z coordinate histories of all of the retro reflective markers were obtained using a commercially available software package (Cortex, Motion Analysis Corporation, Santa Barbara, CA). The coordinate histories were then filtered using a zero lag, 4th order, low pass Butterworth Filter with a 10 Hz cutoff.

The leg making the cut and the type of cut were identified and recorded for each trial using the video data.

The trunk and upper and lower extremities were modeled as an eleven-segment rigid body system with 10, six degree-of-freedom joints interspersed between the segments. A commercially available software package (Orthotrak, Motion Analysis Corporation, Santa Barbara, CA) was employed along with the kinematic model and the coordinate histories of the static and dynamic trials to obtain the three dimensional angular displacement histories for the hip and knee joints bilaterally using an Euler decomposition method (Z,Y,X). The stance phase of the extremity making the cut was extracted and the angular position of the hip and knee joints at 32 ms post foot contact was determined. The time point 32 ms post foot contact was chosen for analysis because previous evidence suggests that ACL injuries occur between 20 and 40 ms post foot contact.33

Figure 3. Anterolateral view of a subject with the full body Cleveland Clinic marker set in place. The marker set consists of four rigid marker triads attached to the distal ends of the femurs and lower legs, single markers placed bilaterally over the midpoint of the acromions, lateral humeral epicondyles, midpoint between the radius and styloid processes, midpoint of the heel counter of the shoes, and over head of the second metatarsals. Four additional makers placed bilaterally over the medial and lateral femoral epicondyles and malleoli were placed during the static trials to establish the location of the hip, knee, and ankle joint centers and removed during the dynamic trials.

Statistical Analysis For each subject, the first two base line trials and the two prolonged activity trials were chosen for all statistical analyses. The frequency of the different cut types performed by subjects at the center cone (Figure 2) in the completion of the agility test was grouped according to activity status (baseline versus prolonged). A Chi-Square analysis was conducted to determine if cut type was associated with prolonged activity status. The angular position data was then grouped according to cut type and prolonged activity status and descriptive statistics consisting of means and standard deviations obtained. A two-factor linear mixed model with fixed effects for cut type and prolonged activity, and a random effect for intercept (unconditioned mean) was employed to determine the effect of cut type and prolonged activity status on the three-dimensional angular position of the hip and knee joints. The alpha level of significance for this study was set at the 0.05 level. SAS v9.3 (SAS, Cary, NC) was used for all statistical analyses.

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RESULTS

During the agility test, subjects performed either a sidestep or crossover cut. In both the baseline and prolonged activity states, the sidestep cut was performed more often than the crossover cut (Figure 4). Within a prolonged activity condition, the mean times to complete the entire agility test were similar for the two cut types (7.1 ± 0.4 and 7.1 ± 0.4 s for the baseline sidestep and crossover cuts, respectively and 7.2 ± 0.3 and 7.5 ± 0.3 s for the prolonged

Figure 4. The number of cuts according to prolonged activity status and cut type.

sidestep and crossover cuts, respectively). Subjects completed an average of 20.6 trials (± 9.4) to complete the agility testing protocol (Table 1). Compared to the baseline trials, athletes after prolonged activity performed the sidestep cut at a higher frequency than the crossover cut; however, this difference was not statistically significant (p=0.074, Figure 4).

An effect of prolonged activity was present for hip joint flexion and extension (F1,57 = 7.11, p = .010).

The hip was more extended after prolonged activity than during the baseline trials (Figure 5). Additionally, an effect of prolonged activity was seen for abduction and adduction (F1,60 = 6.07, p = .017), and flexion and extension (F1,131 = 5.90, p = .016) of the knee. During prolonged activity, the knee was less abducted and more extended than during the baseline trials (Figure 5).

An effect of cut type was seen for internal and external rotation (F1,118 = 90.38, p < .001), abduction and adduction (F1,135 = 430.9, p < .001), and flexion and extension (F1,139 = 10.89, p =.001) of the hip. The hip was more internally rotated, abducted, and extended during a sidestep cut than in the crossover cut during which the hip was more externally

Figure 5. The three dimensional hip and knee angles of the stance limb lower extremity at 32 ms post foot contact according to prolonged activity status. Positive numbers represent hip and knee joint flexion, adduction and internal rotation.

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Figure 6. The three dimensional hip and knee angles of the lower extremity of the stance limb 32 ms post foot contact according to type of cut. Positive numbers represent hip and knee joint flexion, adduction and internal rotation.

rotated, adducted, and flexed (Figure 6). At the knee, an effect of cut type was seen for abduction and adduction (F1,109 = 30.18, p < .001) and flexion and extension (F1,148 = 25.10, p < .001). During the sidestep cut, the knee was abducted and more extended than during the crossover cut (Figure 6). An interaction effect of cut type by prolonged activity status was not present at either joint for any of the joint motions. To determine if past injury affected the above findings all of the models were rerun with

injury included as a factor, and there was no significant effect for injury and injury did not interact with either cut type or prolonged activity on any of the outcomes. While not statistically significantly different, subjects performing the sidestep cuts had more hip internal rotation and less hip and knee flexion after prolonged activity. For the crossover cuts, subjects had less hip external rotation, adduction and flexion and less knee flexion after prolonged activity (Table 2).

Table 2. The three dimensional hip and knee joint angles (degrees) of the lower extremity of the stance limb 32 ms post foot contact according to activity state (baseline or prolonged) and cut type.

Positive numbers represent hip and knee joint flexion, adduction and internal rotation. The plus or minus one standard deviation are noted in the parentheses (± 1 S.D.)

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DISCUSSION In agreement with the authors’ stated hypothesis, prolonged activity placed athletes in a more at risk position. Regardless of which type of cut the subjects performed during the prolonged activity trials, subjects demonstrated less hip and less knee flexion when cutting. This more erect posture during cutting and landing maneuvers has been associated with a greater risk for an ACL injury.1,3,5,13,17 Various researchers using video analysis and observations from the field have suggested that ACL injuries occur when the knee is in a less flexed state, with knee flexion angles ranging from 0° to 40°.1,35,36 In this position, the ACL may be subjected to larger anterior shear forces than at a more flexed position.37 In addition to decreased knee flexion angles, decreased hip flexion angles during landing and cutting maneuvers may increase the risk of non-contact ACL injuries.3 In previous studies, there have been inconsistencies among the effects of prolonged activity on knee flexion angles. Several studies have noted a decrease in knee flexion combined with valgus and tibial external rotation which is similar to the findings of this study, seen during the sidestep cutting prolonged activity trials.17,19,38 A similar study conducted by Lucci et al22 demonstrated that subjects performing an unanticipated sidestep cut after prolonged activity had lower knee and hip flexion angles compared to their baseline trials. In contrast to these findings, Tsai et al39 found no difference in maximum knee flexion angles between prolonged activity and baseline trials during sidestep cutting. A limitation of these previous studies investigating the effects of prolonged activity and cutting kinematics is that the prolonged activity protocol utilized typically consisted of activities that did not mimic competition such as shuttle running, vertical leap jump, or plyometrics. In the present study, the prolonged activity protocol mimicked cutting maneuvers that subjects perform during competition to attempt to better understand how prolonged sport-specific activity potentially alters cutting kinematics. To the authors’ knowledge, this is the first study to use the same activity for both the prolonged activity protocol and for the evaluation of kinematic changes. By having the subjects use the agility test for the prolonged activity protocol and by evaluating how they cut during the performance of

the agility test, it ensures that the task the subjects are performing directly relates to fatigue and mimics a common sport-specific movement pattern.

A unique feature of the present study was that subjects had the ability to choose which type of cut they performed during the agility test. This allowed for a direct comparison of the kinematic differences between these two cut types and if prolonged activity resulted in any kinematic changes. In the present study, cut type affected lower extremity kinematics regardless of prolonged activity status. At the hip, subjects who performed a sidestep cut demonstrated more hip extension, abduction, and internal rotation, and knee extension and abduction than with the crossover cut. Observations by Besier et al20 support the current findings that sidestep cuts elicited greater knee abduction (valgus) and less knee flexion than crossover cuts. The fact that athletes who performed a sidestep cut versus a crossover cut positioned themselves in a more extended and abducted posture suggests that they may be at a greater risk for sustaining an ACL injury than when not in this lower extremity posture. Several studies have shown that during landing and cutting maneuvers, an increase in the knee abduction moments (valgus torques) and knee abduction angles are potentially the most important mechanism for non-contact ACL injuries.17-19 While sidestep cuts may be considered to be more “risky cuts” they were also the most frequently performed cut used by the subjects, regardless of prolonged activity status. While there were no differences in agility times (time to complete the test) between athletes in the present study performing a sidestep or crossover cut, it is possible, that sidestep cuts were chosen by athletes because they may be the more preferred cut from a performance standpoint.40 Therefore, rather than teaching athletes to alter their cutting style future studies aimed at preventing ACL injuries might be best served by allowing athletes to perform sidestep cuts in a more controlled and safe manner that avoids dynamic knee valgus and extension.

In addition, the self-selection of cut type also allowed for an analysis of the effect of prolonged activity on the decision to perform a crossover or sidestep cut.

Although not significant, it is interesting to note that

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subjects during the prolonged activity trials executed sidestep cuts more frequently than crossover cuts as compared to the cuts chosen by athletes during the baseline trials. Therefore, athletes who changed their cut type from a crossover to a sidestep cut during the prolonged activity may further increase their risk for sustaining a non-contact ACL injury. Future studies using larger sample sizes should investigate the effects of prolonged activity on the decision to perform a particular cut.

Several limitations of this study should be noted.

First, due to the relatively small sample size and the large discrepancy between the number of sidestep and crossover cuts the subjects performed, the statistical power for the study was lower than expected.

Given this lower statistical power the potential for making a Type II error and being unable to note a significant difference in some of our outcome variables is a real possibility. Increasing the number of subjects for future studies may allow for a more meaningful statistical comparison between variables. A second limitation is the sample population only included Division I female soccer players, which does not represent other types or skill levels of athletes. This could have altered the outcomes of the kinematic changes because such athletes are trained to perform intense cutting activities. Future studies should look at lower extremity kinematics of athletes performing a cutting maneuver in a variety of athletes who participate in sports such as volleyball, basketball, gymnastics, etc. and at various skill levels. A third limitation of the study was the level and type of fatigue (muscular or central) the subjects achieved during the prolonged activity trials was not determined. In the present study fatigue was defined by a physical decline in performance (slower agility times). The subjects may have achieved central instead of muscular fatigue and may have needed more external motivation through the agility course. However, based on the subject’s inability to complete the task and the fact that the subjects were Division I athletes, muscular and not central fatigue was likely achieved. Both types of fatigue may be critical in determining why subjects are more likely to become injured late in competition. Future studies should include a physiological measurement such as oxygen consumption, heart rate, or blood lactate levels to help determine

which type of fatigue subjects attained during prolonged activity. Lastly, while the subjects were able to select the type of cut they performed, the cutting maneuvers were still anticipated. This, however, is not the case during competition. In a game scenario, players must react quickly to unanticipated stimuli, such as a defender, and manage other distractions during play. Therefore, future studies should focus on examining the cutting maneuvers chosen by athletes in response to unanticipated stimuli, and if this reaction places them in a position that is more prone to injury.

CONCLUSIONS The results of the present study demonstrated that prolonged activity appears to predispose an athlete to position the knee in a more extended and adducted posture and the hip in a more extended posture during cutting maneuvers. The extended positions of the hip and knee have been suggested to place greater stress on the ACL and potentially increase the risk for injury. Interestingly, subjects chose to perform sidestep cuts more often than crossover cuts during an agility test regardless of activity status. In agreement with previous studies, the current results suggest that sidestep cuts may place the athlete at greater injury risk due to less hip and knee flexion and greater knee abduction angles compared to crossover cuts. Therefore, future studies need to account for the effects of prolonged activity as well as cut type when evaluating an athletes’ risk for injury.

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IJSPT

ORIGINAL RESEARCH

COMPARISON OF ISOMETRIC ANKLE STRENGTH BETWEEN FEMALES WITH AND WITHOUT PATELLOFEMORAL PAIN SYNDROME Ana Paula de Moura Campos Carvalho e Silva, PT, MSc Student1 Eduardo Magalhães, PT, Msc2 Flavio Fernandes Bryk, PT3 Thiago Yukio Fukuda, PT, PhD3

ABSTRACT Introduction: Proximal and distal influences on the knee may be related as etiological factors of patellofemoral pain syndrome (PFPS). The distal factors include subtalar excessive pronation as well as medial tibia rotation, but no study has investigated whether ankle weakness could lead to alterations that influence the patellofemoral joint. Thus, the purpose of this study was to compare the ankle dorsiflexor and invertor muscles strength, as well as rearfoot eversion and the Navicular Drop Test (NDT) in females with PFPS to a control group of females of similar demographics without PFPS. Methods: Forty females, between 20 and 40 years of age (control group: n=20; PFPS group: n=20) participated. Rearfoot eversion range of motion and the NDT were assessed for both groups. The Numeric Pain Rating Scale and the Anterior Knee Pain Scale were used to evaluate the level of pain and the functional capacity of the knee during activities, respectively. Isometric ankle dorsiflexor and invertor strength was measured using a handheld dynamometer as the dependent variable.

Results: The isometric strength of the dorsiflexor and invertor muscle groups in females with PFPS was not statistically different (P>0.05) than that of the control group. There was no statistically significant difference between groups for rearfoot eversion and NDT (p>0.05).

Discussion/Conclusion: These results suggest that there is no difference between isometric ankle dorsiflexion and inversion strength, the NDT, and rearfoot eversion range of motion in females with and without PFPS. Key words: Ankle, handheld dynamometer, knee, patella, strength Level of evidence: 3-b

1

Universidade de São Paulo, Physical Therapy Department, São Paulo, Brazil 2 Federal University of São Paulo, São Paulo, Brazil 3 Irmandade da Santa Casa de Misericórdia, Physical Therapy Department, São Paulo, Brazil

CORRESPONDING AUTHOR Thiago Yukio Fukuda Adress: Rua Cesario Mota Jr. 112; 01221-020, São Paulo-SP, Brazil. e-mail: tfukuda10@yahoo.com.br

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INTRODUCTION Patellofemoral pain syndrome (PFPS) is the most common source of anterior knee pain in athletes and sedentary women, representing 20 to 40% of all individuals that are treated for knee injuries in orthopedic rehabilitation centers.1 Traditionally, the treatment of PFPS has focused on addressing structures about the knee joint, including quadriceps strengthening and hamstring and iliotibial flexibility, in order to decrease patellar maltracking and normalize patellofemoral contact.2 Recently, PFPS has been related to dynamic lower limb malalignment including excessive femoral medial rotation and adduction during eccentric daily activities, resulting in reduction of contact area in the patellofemoral joint.3-6 However the dynamic increase of tibiofemoral internal rotation could also decrease the patella to femur contact.7 Excessive or prolonged rearfoot eversion during gait could lead to a compensatory mechanism, causing an increase tibiofemoral internal rotation and consequently an excessive dynamic valgus.3,8,9 Baldon et al10 observed that greater rearfoot eversion (pronation of the foot) was associated with greater tibial internal rotation in subjects with PFPS. Based upon these biomechanical findings, many authors have recommended the use of foot orthoses to positively affect the alignment of the lower extremities, resulting in significant short and long-term satisfactory clinical outcomes.11-13 Thus, controlling excessive foot pronation may decrease the tibial and femoral internal rotation, thereby decreasing overload of the patellofemoral joint.5,14,15 The authors of this study believe that excessive foot pronation and calcaneal eversion during the midstance phase of gait could be the result of a muscular imbalance, related to dorsiflexor and invertor musculature weakness, especially the tibialis posterior muscle, which is assists in maintaining the medial longitudinal arch.16 With these concepts in mind, Barton et al17 and Powers et al18 suggested that increased foot pronation may be contributing factor in PFPS. Therefore, the aim of the current study was to compare the ankle dorsiflexor and invertor muscles strength, as well as rearfoot eversion and NDT in females with PFPS to a control group of females of similar demographics without PFPS.

The authors hypothesized that when compared to a pain-free control group, females with PFPS would exhibit decreased ankle strength and increased rearfoot eversion and navicular drop. This study may help in the clinical understanding of the relationship between ankle muscle strength and PFPS. METHODS Subjects Twenty females between the ages of 20 and 40 years (mean 23.0 ± 3.0 years; height 162.0 ± 7.0 cm; body mass 56.8 ± 10.0 kg) diagnosed with unilateral (n=7) or bilateral (n=13) PFPS were recruited from the Physical Therapy sector of the Irmandade Santa Casa de Misericordia de São Paulo Hospital. The inclusion criteria for the PFPS group were the same criteria described by Thomee et al.19 Pain during at least 3 of the following activities: squatting, climbing up or down stairs, kneeling, sitting for long periods, or when performing resisted isometric knee extension at 60 degrees of knee flexion; insidious onset of symptoms unrelated to trauma and persistence for at least 4 weeks; and pain on palpation of the medial or lateral facet of the patella.

Twenty control females (mean ± SD age, 24.0 ± 3.0 years; height, 163.0 ± 6.0 cm; body mass, 61.9 ± 10 kg), who presented with upper extremity tendinopathies and without lower extremity involvement were recruited from the same sector to serve as the control group. The exclusion criteria for both groups included the presence of any other associated knee conditions including patellar instability, patellofemoral joint dysplasia, meniscal or ligament injuries, tendon or cartilage injury, a decrease of range of motion in dorsiflexion, and a history of inversion injuries within the last 2 years. Subjects were also excluded if they had any neurological diseases, previous surgery of the lower limbs, lumbar pain, sacroiliac joint pain, rheumatoid arthritis, or were pregnant.

It is important to highlight that all females included in both groups were active, but not competitive athletes.20 Before taking part in this study, the subjects were informed of the procedures and signed an informed consent approved by the Ethics Committee on Research of the ISCMSP.

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Procedures A senior physical therapist determined subject participation in both groups based on the inclusion and exclusion criteria. The subjects completed the Anterior Knee Pain Scale (AKPS) and a verbal numeric pain rating scale (NPRS). Another evaluator, who was blinded to group assignment, measured all subjects for the NDT and rearfoot eversion bilaterally, followed by ankle manual muscle strength assessment. The data for pain, function, duration of symptoms, ankle strength, rearfoot eversion and NDT for the PFPS group were obtained from the affected limb of the subjects with unilateral PFPS and the most affected limb of subjects with bilateral PFPS. In relation to control, the authors used the mean value of both sides for data analysis.

Functional Evaluation The Anterior Knee Pain Scale (AKPS) was used to measure self-reported function.21 The AKPS contains 13 items, each based on a 6-point scale, where the highest score represents no difficulty when performing the task and the lowest score represents complete inability to perform the activity. The maximum score is 100 and indicates that there is no deficiency; a score below 70 suggests moderate pain and disability. This questionnaire is reliable and valid, and has been widely used for patients with PFPS.22,23 Pain was measured with an verbal 11-point Numeric Pain Rating Scale (NPRS) where 0 corresponded to no pain and 10 corresponded to “worst imaginable pain”.1,24 Foot evaluation Foot pronation was assessed using the NDT.25,26 This test measures the difference in millimeters of the navicular tuberosity from the ground between a relaxed, weight bearing position, and a position of “imposed” subtalar neutral in standing. Initially, the subjects were placed on a rigid surface and placed in a neutral subtalar joint position, and the navicular height was measured. Next, the subjects were asked to relax and stand in their preferred posture, and the measurement was repeated.25 In the authors’ laboratory the reliability for NDT, was 0.80 (ICC2,1) and SEM 0.20mm.

Then, the therapist passively positioned the calcaneus in maximum eversion and motion was measured with a goniometer, and named rearfoot eversion.27 The reliability for rearfoot eversion in the authors’ laboratory28 was 0.82 (ICC2,1) and SEM 0.75 degrees.

Figure 1. Strength measurement for the dorsiflexor (A) and invertor (B) musculature

Isometric Muscle Strength A Nicholas hand-held dynamometer (Lafayette Instrument Company, Lafayette, IN) was used to measure isometric strength during a “make test” of the ankle dorsiflexors and invertors. This instrument is widely used clinically to measure muscle isometric strength.29-31 The dorsiflexor ankle strength was assessed while the subject lying in a supine position. The evaluated limb was positioned with the extended knee and the ankle joint remained in an unrestrained and neutral position. The dynamometer was placed against the dorsal surface of the foot near the metatarsal heads (FIGURE 1-A).32 In the authors’ laboratory, reliability for isometric muscle strength measurement of the dorsiflexors28 was 0.95 (ICC2,1) and SEM of 1.00 kg.

The invertor muscles were evaluated with the subject in the same position and the dynamometer was placed on the medial border of the foot at the shaft midpoint of the first metatarsal (FIGURE 1-B).32 In the authors’ laboratory, reliability for isometric muscle strength measurement of the invertors28 was 0.77 (ICC2,1) and SEM 1.97 kg.

During isometric strength testing, two submaximal trials were allowed for the subject to become familiar with each test position. This was followed by two trials with the subject providing maximal isometric effort for each muscle group, using consistent verbal encouragement. The interval between the second submaximal contraction and the first maximum isomet-

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ric contraction was 10 seconds. The duration of each maximum isometric contraction was standardized at 5 seconds, with a rest time of 30 seconds between maximum isometric contractions. Testing order for the muscle groups was randomized. After evaluation of a muscle group, a standard 1-minute rest period was given before evaluating the other muscle group.

When the examiner observed any compensation or combined movements during a test, the values were disregarded and the test was repeated after 20 seconds of rest. The mean values of the two maximal effort trials (one mean for each of the tested muscle groups) were utilized for data analysis.

Data Reduction Isometric strength measurements, measured in kilograms (Kg), were normalized to body mass, also reported in Kg by using the following formula: (Kg strength / Kg body weight) x 100.29,33

Data Analysis Normality was assessed using Shapiro-Wilk test. Independent t-test were used to measure and compare demographics data, NPRS scores, AKPS scores, normalized dorsiflexor and invertor isometric strength; and the Mann-Whitney test was used to compare the NDT and rearfoot eversion measurements between groups. SigmaStat 3.5 was used for data analysis and the alpha level was set at 0.05.

RESULTS Demographic data for the PFPS group and the control group are provided in Table 1. The PFPS and the control group were not statistically different in terms of age, weight, and height (p>0.05).

Dorsiflexor and invertor muscle strength, NDT measurements, and the rearfoot eversion measurements of both groups are presented in Table 2. There were no statistically significant differences in normalized

Table 1. Baseline characteristics (Mean ± SD) of the subjects in the control group (n = 20) and PFPS group (n = 20).

Age*

Height*

Body mass*

Duration of Symptoms‡

NPRS‡

AKPS‡

(cm)

(Kg)

(months)

(0-10)

(0-100)

Control

24.1 ± 2.6

163.0 ± 6.0

61.9 ± 10.0

0.0

0.0

98.4 ± 2.3

PFPS

22.8 ± 2.8

162.0 ± 7.0

56.8 ± 10.0

28.0 ± 18.0

6.0 ± 1.8

78.9 ± 17.2

Abbreviations: AKPS, Anterior Knee Pain Scale; NPRS, Numerical Pain Rating Scale; PFPS, Patellofemoral Pain Syndrome * No difference between groups (p>0.05) ‡ Statistically significant difference between groups (p<0.01)

Table 2. Results for ankle strength of dorsiflexors and invertors, Navicular Drop Test, and rearfoot eversion (mean ± SD).

Dorsiflexors‡ (kg)

Invertors‡ (kg)

Navicular Drop Test (mm)

Rearfoot eversion (degrees)

Control (n = 20)

31.2 ± 11.4

29.0 ± 7.5

0.8 ± 0.3

9.0 ± 2.2

PFPS (n = 20)

32.4 ± 11.0

30.0 ± 8.4

0.9 ± 0.5

7.6 ± 2.5

0.8

0.6

0.4

0.3

p Value*

PFPS= Patellofemoral pain syndrome * Note: There were no significant differences between groups. ‡ Reported normalized to body weight

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dorsiflexor (p=0.80) and invertor (p=0.60) muscle strength between the PFPS group and the control group. Moreover, the NDT and the rearfoot eversion measurements were not significantly different (p = 0.40 and p = 0.30, respectively) between groups.

DISCUSSION The purpose of this study was to compare ankle dorsiflexion and inversion isometric strength, measures of foot pronation and rearfoot eversion between sedentary women with and without PFPS. There were no differences between groups, thus rejecting the authorsâ&#x20AC;&#x2122; initial hypothesis.

Faulty mechanics at the hip have been correlated with PFPS, particularly excessive femoral adduction and internal rotational.3,4 Strengthening of the hip abductor and external rotators is commonly recommended in the management of this disorder.29,34,35 Similarly, faulty mechanics of the foot and ankle distally have been implicated in PFPS including excessive foot pronation and internal tibial rotation resulting in medial femoral rotation and increased patellofemoral stress.4,5,18,36,37 It is not surprising that the subjects in this study did not differ in ankle strength from the control group.

Piazza38 stated that when the foot is in a pronated position, the anterior tibialis would present an active restraint to pronation, thereby losing it is function as a rearfoot invertor. Then, one possible reason for the lack of differences between groups in the current study is the fact that the invertor muscles did not lose their function, since the subjects and controls did not differ in relation to foot pronation (as measured using the NDT) or rearfoot eversion.38 In contrast to the current findings, Barton et al39 inferred that subjects with PFPS would present with greater navicular drop measurement when compared to controls. However, even if a difference had been found in NDT between groups, maybe that would not interfere with isometric strength of the chosen ankle muscles, since Snook40 did not find a positive correlation between excessive pronation and ankle muscle weakness in healthy population.

Some authors have reported that the foot remains pronated when it should already be supinated during closed chain activities such as walking, running

and other functional activities in subjects with PFPS, resulting in excessive internal tibial rotation.3,41 So, this suggests a possible delay in the activation time of rearfoot inversion during these activities.11,12,41 Many authors have surmised that this inversion occurs due to muscular delayed activation or pre vious muscle fatigue, instead of actual ankle muscle weakness, thus subjects with PFPS may not present with weakness of the inverters and dorsiflexors.5,9,18,42 Other factors that could be related would be the difference between available ankle range of motion (ROM) and pronation velocity during closed chain activities in subjects with and without PFPS, however these two constructs were not studied in the current research.43 Another contributor to PFPS may be excessive hip adduction and internal rotation. Fukuda et al35 and Mascal et al34 observed that after a hip abductor and external rotator strengthening program, subjects with PFPS showed significant clinical improvement in terms of function and pain relief. Corroborating these data, some authors demonstrated that an associated 6-week strengthening program focusing on hip abductor and external rotator strengthening, can control the dynamic tibial internal rotation during jogging, thus decreasing the eversion amplitude and the inversion rearfoot moment.42 Some limitations of this study include the method of muscle strength evaluation, due to lack of other evidence regarding ankle muscle isometric dynamometry. Also, handheld dynamometry testing is both examiner- and test-position dependent. However, a pilot study was previously performed by the authors in order to establish reliability, and demonstrated satisfactory to excellent reliability. It is important to highlight that other options for assessment methods of rearfoot eversion could have been used, such as plain film radiographs or motion analysis during a dynamic gait task. However, we chose the NDT and eversion range of motion measures because they are widely used methods in the clinical practice with good to excellent interrater and intrarater reliability for patients with patellofemoral pain syndrome.24 To the authorsâ&#x20AC;&#x2122; knowledge, this is the first study focusing on the measurement of isometric ankle muscle strength of the PFPS population. Therefore, future studies are needed to better understand the rela-

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tionship between such variables as ankle muscle strength and patellofemoral contact area, as well as the possible influence of the timing of muscle activation using electromyography and kinematic assessments of changes during functional activities.

Finally, the main clinical implication of this study is that there were no statistical differences in the ankle muscle strength measurements, and measures of foot pronation and rearfoot eversion between PFPS and control groups.

CONCLUSION The results of this study indicate that there is no difference in nomalized isometric ankle strength in women with PFPS and those without. When compared to a matched control group, neither the NDT nor the rearfoot eversion measurements were statistically significantly different.

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32. Spink MJ, Fotoohabadi MR, Menz HB. Foot and ankle strength assessment using hand-held dynamometry: reliability and age-related differences. Gerontology. 2010;56(6):525-532.

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IJSPT

ORIGINAL RESEARCH

THE EFFECT OF EXERCISE AND TIME ON THE HEIGHT AND WIDTH OF THE MEDIAL LONGITUDINAL ARCH FOLLOWING THE MODIFIED REVERSE-6 AND THE MODIFIED AUGMENTED LOW-DYE TAPING PROCEDURES Mark W. Cornwall, PT, PhD, FAPTA1 Thomas G. McPoil, PT, PhD, FAPTA2 Austin Fair, PT, DPT3

ABSTRACT Purpose/Background: No evidence exits regarding the magnitude of the change in foot posture following the “modified reverse-6” (MR6) taping procedure, either alone or in combination with the “low-dye” (LD) taping technique. The purpose of this study was to investigate the change in the height and width of the midfoot after application of the MR6 and the MR6 plus the LD (MR6+LD) taping technique and determine how long those changes last.

Methods: Eleven individuals (2 female and 9 male) were recruited for this study and were tested under each of two experimental conditions, the MR6 and the MR6+LD taping technique. The order of testing for the two conditions was randomly determined. For each condition, the height and width of the midfoot at 50% of each subject’s foot length was initially measured and then again immediately following the application of the tape. These measurements were repeated four hours later immediately prior to running two miles on a treadmill, again immediately after running, and finally after another four hours.

Results: The dorsal arch height increased significantly with both the MR6 and MR6+LD taping, but only the MR6+LD remained statistically greater after four hours, a bout of exercise and again at the end of the day. The mean width of the midfoot significantly decreased with both taping procedures. The change in the width of the midfoot remained significantly decreased in both taping conditions after exercise and throughout the day.

Conclusions: Both taping procedures are able to significantly change the height and width of the medial longitudinal arch of the foot, but the change lasted longer when the two taping procedures were combined.

Levels of Evidence: Level 3, Prospective Cohort Study Keywords: Adhesive Taping, Durability, Foot and Ankle

1

Department of Physical Therapy and Athletic Training, Northern Arizona University, Flagstaff, AZ, USA 2 School of Physical Therapy, Regis University, Denver, CO, USA 3 Kinect Physical Therapy, Chandler, AZ, USA This study was approved by the Institutional Review Board at Northern Arizona University, Flagstaff, AZ.

CORRESPONDING AUTHOR Mark W. Cornwall, PT, PhD, FAPTA Department of Physical Therapy and Athletic Training P.O. Box 15105, Northern Arizona University Flagstaff, Arizona 86011 928-523-1606 E-mail: mark.cornwall@nau.edu

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INTRODUCTION Anti-pronation taping has been advocated by several authors to reduce pain and symptoms caused by excessive foot pronation.1-5 Although several different taping techniques have been described in the literature to limit excessive foot pronation, the “low-dye” and “Reverse-6” techniques have received the greatest attention. The low-dye (LD) technique was originally described by Dr. Ralph Dye and has been shown to increase the height of the medial longitudinal arch1,6-9 as well as provide short-term relief of symptoms associated with plantar fasciitis.3,8,10 The mean reported change in the height of the medial longitudinal arch using the LD technique with individuals demonstrating mild to moderate calcaneal eversion and a mild to moderate decrease in the height of the medial longitudinal arch on weight bearing was 4.5mm with a range of between 3.1mm to 7.2mm.1,6,7,9 In a recent systematic review, Cheung et al11 reported that while adhesive taping was more effective than footwear and foot orthoses in controlling foot pronation, the low-Dye technique was less effective than other taping techniques such as the Reverse-6 that is applied with portions of the tape proximal to the talocrural joint. The Reverse-6 taping (R6) technique therefore traverses both malleoli and has been advocated to control excess foot pronation.5,12 Previous research, however, has indicated that talocrural joint range of motion, especially plantar flexion, may be restricted when tape is applied in this manner.13 Vicenzino et al reported that combining the LD and R6 taping techniques resulted in a greater change of the height of the navicular bone.5 The combining of the LD and R6 taping techniques was referred to as the “Augmented Low-Dye” (ALD).4,14-16 The mean reported change in the height of the medial longitudinal arch using the ALD technique with individuals who had at least a 10mm navicular drop was 9.4mm with a range of between 8.0mm to 10.8mm.4,15 Inelastic tape has been used almost exclusively with either the LD or R6 taping techniques in order to control foot pronation and restrict foot movement.10,15,17,18 Only one published study was found in which elastic tape was used to restrict motion of the medial longitudinal arch. This study was a case series and reported on the use of a “modified” R6 tap-

ing technique using elastic tape to not only reduce symptoms of excess foot pronation, but also as a way to determine the degree of orthotic posting based on the amount of change seen in the height of the medial longitudinal arch following taping.19 In that study, the original R6 taping technique described by Vicenzino et al5 was modified by first altering the path of the tape so that it did not cross the medial or lateral malleoli and possibly hinder talocrural joint range of motion and second by using elastic rather than inelastic tape to improve comfort.19 While the Meier et al case series study demonstrated that the “modified Reverse-6” (MR6) taping technique was clinically effective, it is unclear exactly how much foot motion was actually restricted as well as how long the effect of the tape lasted. In addition, it is unknown whether the combination of the LD and the MR6 techniques may be more effective than just using the MR6 procedure.

Numerous researchers have investigated the effect of exercise on the ability of taping procedures to maintain the observed postural changes in the foot.1,7,8,17,20 Using just the LD taping procedure, Holmes, et al reported that in individuals with a pronatory foot posture, arch height increased by 7.2mm immediately following taping and was reduced to 4.4mm after 10 minutes of walking. Ator and colleagues reported a 3.8mm increase in the height of the navicular bone immediately following application of the LD taping technique in individuals with a pronatory foot posture, but this was reduced to just 1.45mm after 10 minutes of jogging.1,7 On the other hand, Vicenzino and associates reported that the height of the navicular bone was increased by 8.6% immediately after applying the LD technique to otherwise healthy females with observable increased foot pronation. The height of the navicular bone was reduced to 94.2% of the person’s resting navicular bone height (14.1% reduction) after 10 minutes of jogging. The navicular bone height was 91.3% of the person’s resting navicular bone height (17.0% reduction) after 20 minutes of jogging.5 The studies using the “augmented low-dye” procedure reported between 12.9% to 18.8% or 5.9mm to 8.0mm increase in arch height immediately following application of the tape.4,5,14 After 10 minutes of exercise, arch height remained 8.6% or between 5.0mm and 5.9mm higher than before the tape was

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applied.4,5,14 After 20 minutes of exercise, arch height was 5.7% or 3.5mm higher than before the tape application.4,5 Again, each of the previously cited studies utilized inelastic tape. No such studies have been conducted specifically looking at the MR6 taping procedure using neither elastic tape nor its combination with the LD taping procedure on the height or width of the midfoot. Cornwall and associates, however, did report that the MR6 taping technique can be applied consistently from one session to the next as well as between therapists. In that study, they reported a 3.9mm increase in the height of the medial longitudinal arch after the application of the tape.21 The purpose of this study was two fold. First, investigate the change in the height and width of the midfoot after application of the MR6 and the MR6 plus the LD (MR6+LD) taping technique, and second, determine how long those changes last over time and after a single bout of exercise.

METHODS Because this study involved the use of two commonly used anti-pronation taping procedures, only individuals with a Foot Posture Index of +4 or greater were included in this study. A minimum FPI of +4 or greater was chosen because it represents subjects with a pronatory foot posture in which foot taping is likely to be used in a clinical setting to either control motion and reduce a patient’s symptoms. Thirteen individuals (4 women, 9 men) with a mean age of 27.3 years and without a history of injury or pain to either of their feet for at least 6 months prior to participating in the study were recruited (Table 1). The Internal Review Board at Northern Arizona University approved the study and all of the subjects read and signed an informed consent prior to participating.

before 8:00am on the day of data collection. After measuring each subject’s height and weight, the Foot Posture Index (FPI) of each subject’s foot was assessed using the methods described by Redmond.22 The FPI has been shown to have good intra-clinician reliability (ICC=0.928 to 0.937) and moderate interclinician reliability (ICC=0.525 to 0.655).23 Next, each subject was asked to stand on a foot measurement platform that has previously been described

by McPoil et al.24,25 Using this platform, the height of the dorsum of the arch (DAH) and the width of the mid-foot (MFW) were measured using a digital caliper (Mitutoyo America Corporation, Aurora, IL) at 50% of the subject’s overall foot length. (Figure 1) All measurements of dorsal arch height and midfoot width were performed by one of the paper’s authors (AF) using the methods described by McPoil et al which have been shown to be reliable.25 The subjects were then randomly assigned to one of the two taping conditions; 1) the “modified Reverse-6” using elastic tape (MR6) or 2) the “modified Reverse-6” using elastic tape plus the low-dye technique using cloth tape (MR6+LD). Immediately following the application of the tape, the subject’s dorsal arch height and midfoot width was measured again. (Figure 2). After the second set of measurements, the individual was instructed to go about their normal daily activities, but to refrain from exercise or any vigorous activity. At noon on the test day (four hours after being taped), subjects returned to the laboratory and again DAH and MFW measurements taken. Immediately following this third set of measurements, the subject ran on a treadmill at a self-selected speed for

All subjects reported to the Laboratory for Foot and Ankle Research at Northern Arizona University Table 1. Demographic Information on the Subjects Used in the Study. Values in Parentheses are Standard Deviations.

Female (n=4) Male (n=9) Total (n = 13)

Age (yrs.)

Height (cm)

Weight (kg)

FPI

30.8 (6.7) 25.8 (1.3) 27.3 (4.3)

169.8 (2.1) 179.8 (4.9) 176.7 (6.3)

61.8 (6.6) 78.3 (8.4) 73.2 (11.0)

5.1 (2.0) 7.0 (2.1) 6.5 (2.2)

Figure 1. (a) Photo of Measuring the DAH at 50% of Overall Foot Length Prior to Tape Application. (b) Photo of Measuring the MFW at 50% of Overall Foot Length Prior to Tape Application.

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Figure 2. (a) Photo of Measuring the DAH at 50% of Overall Foot Length After Tape Application. (b) Photo of Measuring the MFW at 50% of Overall Foot Length After Tape Application

two miles. Immediately following the exercise intervention, DAH and MFW measurements were taken again. After this fourth set of measurements, subjects were again asked to go about their normal daily activities, but refrain from exercise or any vigorous activity. Finally, subjects returned to the laboratory for a final time at approximately 5:00pm and the DAH and MFW were measured for the fifth and last time. After this final measurement, the tape was removed and its thickness was measured in the regions where the foot measurements were obtained using a digital caliper so that this value was not included in the change in navicular height or width from the pre-tape condition. One week later, each subject returned to the laboratory and the entire above procedure was repeated except that the other taping procedure was applied.

the medial longitudinal arch. Tests of normalcy and homogeneity of variance were performed to ensure that subsequent use of inferential statistical analyses were appropriate. Two-way analysis of variance (ANOVA) tests were used to determine if there was a significant difference between the two taping procedures or time on the height and width of the medial longitudinal arch. If a significant interaction effect was found, a repeated measures one-way analysis of variance (ANOVA) was performed for each tapping condition followed by simple contrast comparisons of each time period with that of the first time period.

Finally, a series of t-tests were used to determine if there was a significant difference between the two taping procedures at each of the measured time periods. In order to compensate for the large number of statistical comparisons performed, an alpha level of 0.02 was used for all individual and group tests of statistical significance.

RESULTS Main Effects.

The result of the 2-way ANOVA test of DAH showed that there was a significant (p=0.016) main effect between the two taping conditions and the five time periods (p=0.000). There was no significant (p=0.133) interaction, however between the two main effects.

The result of the series of t-tests indicated that arch height was significantly (p<.02) different between the two taping procedures for each time measurement except for the initial measurement before the tape was applied. See Table 2 and Figure 3.

The MR6 taping technique used in this study was the same as described by Meier,et al and utilized elastic tape (Elastakon®, Johnson & Johnson, New Brunswick, NJ).19 The LD taping technique used in this study followed that described by several previous researchers and utilized cloth athletic tape (Coach Athletic Tape®, Johnson & Johnson, New Brunswick, NJ).6,17,26 A single person (MWC) applied each of the taping techniques on all subjects. This person was a licensed physical therapist with over 30 years of clinical experience, including frequent application of both taping techniques.

The result of the 2-way ANOVA test of MFW showed that there was a significant (p=0.005) main effect between the two taping conditions and the five levels of time periods (p=0.000). There was no significant (p=0.334) interaction, however between the two main effects. The result of the series of t-tests indicated that midfoot width was significantly (p<.02) different between the two taping procedures for each time measurement except for the initial measurement before the tape was applied. See Table 2 and Figure 4.

Statistical Methods Descriptive statistics were used to represent subject demographics as well as the height and width of

Modified Reverse-6 Technique.

Table 3 contains the mean values of the DAH and MFW over time for the MR6 condition. As can be

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Table 2. Mean Values for Dorsal Arch Height and Midfoot Width at Each Measurement Time Period and For Each Taping Procedure. Values in Parentheses Are Standard Deviations.

Variable Time DAH T0 (Pre)

MR6 MR6+LD 63.5 63.8 (5.1) (5.3) T1 (Immed Post) 65.8 67.0 (4.8) (4.6) T2 (Post 4 hrs.)

64.1 65.2 (5.0) (4.7) T3 (Post Ex) 63.9 64.8 (5.3) (4.6) T4 (Post 8 hrs.)

63.8 65.0 (5.0) (4.9) MFW T0 (Pre) 84.6 85.1 (6.1) (6.4) T1 (Immed Post) 82.2 83.4 (5.7) (5.4) T2 (Post 4 hrs.)

82.0 83.4 (5.5) (5.2) T3 (Post Ex) 83.2 84.2 (5.5) (5.6) T4 (Post 8 hrs.)

82.2 83.6 (5.3) (5.6) DAH= Dorsal arch height; MFW= Midfoot width

p-value 0.244 0.470 0.024 0.041 0.017 0.270 0.041

Figure 4. MFW Over Time For the Modified Reverse-6 and the Modified Reverse-6 Plus Low-Dye Taping Procedures.

Error Bars Represent Standard Errors of the Mean.

0.003 0.015 0.006

Figure 3. DAH Over Time For the Modified Reverse-6 and the Modified Reverse-6 Plus Low-Dye Taping Procedures.

Error Bars Represent Standard Errors of the Mean.

seen, DAH increased by an average of 2.2mm immediately after applying the tape and then decreased by 77.3% after four hours of general activity to 63.6mm.

After running two miles, the DAH decreased another 4.5% to 63.5mm and by the end of the day the DAH was only .3mm above the pre-tape condition, which meant that the height of the arch was only 4.5% above the pre-tape condition. The result of the oneway ANOVA test and post-hoc comparisons indi-

Table 3. Mean Values of the Dorsal Arch Height and Width of the Over Time for the Modified Reverse-6 Taping Technique. Values in Parentheses are Standard Deviations.

DAH MFW (mm) (mm) 63.5 84.6 Pre-Tape (5.1) (6.8) 65.8 82.2 Post-Tape (0 Hours) (4.9) (6.6) 64.1 82.0 Pre-Exercise (4 Hours) (5.0) (6.4) 63.9 83.2 Post-Exercise (4.5 Hours) (5.3) (6.4) 63.8 82.2 Post-Exercise 2 (8 Hours) (5.0) (6.2) DAH= Dorsal arch height; MFW= Midfoot width

cated that only the DAH measurement immediately after taping the foot was significantly different from the pre-taping measurement (p=0.000). See Table 3 and Figure 5a.

The MFW decreased by an average of 2.8% or 2.3mm immediately after applying the tape and then decreased another 0.2mm after four hours of general activity. After running two miles, the MFW had increased by 1.1mm and after another four hours of general activity, the MFW had decreased 0.9mm.

The result of the one-way ANOVA test and post-hoc comparisons indicated that each of the MFW measurements while the foot was taped was significantly less (p=0.000) compared to the pre-taping measurement. See Table 3 and Figure 5b.

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Table 4. Mean Values of the Dorsal Arch Height and Width of the Midfoot Over Time for the ModiďŹ ed Reverse-6 Plus Low-Dye Taping Techniques. Values in Parentheses are Standard Deviations.

DAH MFW (mm) (mm) 63.8 85.1 Pre-Tape (5.5) (6.9) 67.0 83.4 Post-Tape (0 Hours) (4.8) (5.7) 65.2 83.4 Pre-Exercise (4 Hours) (4.9) (5.5) 64.8 84.2 Post-Exercise (4.5 Hours) (4.7) (6.0) 65.0 83.6 Post-Exercise 2 (8 Hours) (4.9) (5.8) DAH= Dorsal arch height; MFW= Midfoot width

Figure 5. DAH (a) and MFW (b) Over Time for the MR6 Taping Condition. Error Bars Represent Standard Errors of the Mean.

ModiďŹ ed Reverse-6 Plus Low-Dye Technique.

Table 4 contains the mean values of the DAH and MFW over time for the MR6 condition. As can be seen, DAH increased by an average of 3.1mm or 4.9% immediately after applying the tape and then decreased by 1.7mm after 4 hours of general activity.

After running 2 miles, the DAH decreased another 0.4mm and by the end of the day, the DAH was only 1.9mm above the pre-tape condition. The result of the one-way ANOVA test and post-hoc comparisons indicated that the DAH measurement was still significantly (p=0.000) different from the pre-taping measurement after wearing the tape for 8 hours and after running for 2 miles. See Table 4 and Figure 6a.

The MFW decreased by an average of 1.5mm immediately after applying the tape and then decreased only another 0.02mm after four hours of general activity. After running two miles, the MFW rather than decreasing, increased by 0.7mm and after another 4 hours of general activity, the MFW had again decreased by 0.4mm. The result of the oneway ANOVA test indicated that each of the MFW measurements while the foot was taped was signif-

Figure 6. DAH (a) and MFW (b) Over Time for the MR6+LD Taping Condition. Error Bars Represent Standard Errors of the Mean.

icantly less (p=0.027) when compared to the pretape measurement. See Table 4 and Figure 6b.

DISCUSSION Both of the taping procedures utilized in this study were able to significantly increase the height of the dorsal arch and decrease the width of the midfoot

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immediately after the tape was applied. There was, however, no statistical difference between the two taping procedures in their ability to maintain this change.

The magnitude of change in the height of the arch seen in the current study is smaller than the majority of previously published literature using other taping techniques. Previous studies have reported increases of 3.8mm,1 4.0mm,9 and 7.2mm7 in the height of the arch using the low-dye taping technique. A systematic review reported that the low-dye taping technique resulted in a 5.9mm increase in arch height.27 In contrast, however, a 3.1mm increase in the height of the medial longitudinal arch was reported by Whitaker, et al using the low-dye taping procedure, which is much closer to what has been found in the current study.6 Previous research using the “augmented” low-dye technique have reported 8.0 and 10.8mm increases in the arch height.4,14 The smaller change scores obtained in the current study may be related to the use of elastic rather than inelastic tape. Abian et al, however, demonstrated that elastic tape limited motion of the ankle to a greater extent than inelastic tape, even after 30 minutes of vigorous exercise, which would be a significant advantage of elastic tape over inelastic tape.28 Another possibility for the smaller observed change in arch height may be related to the subjects sampled in the current study. Although the current study only included those individuals with an FPI greater than or equal to +4, it is possible that the subject’s foot mobility did not allow for large changes in arch height. For example, Vicenzino et al included only those individuals with a navicular drop of at least 10mm in their study and reported a change of 10.8mm in arch height immediately after applying the “augmented” low-dye taping procedure.4 It is important to note, that Meier and colleagues19 obtained a reduction in foot related symptoms with an average change in dorsal arch height of 2.6mm. As such, it appears that a relatively small change in dorsal arch height may reduce tissue loading of the foot and therefore impact a patient’s symptoms. Certainly, further research is warranted dealing with the use of elastic rather than inelastic tape as well as determining the minimal change in the medial longitudinal arch height that is necessary to produce positive clinical outcomes.

The observed change in the width of the midfoot in the current study cannot be compared to previous

research as no studies could be found that looked at this variable following taping. Because foot pronation involves movement in both the frontal and transverse plane, the addition of midfoot width in the current study provides additional information regarding how taping may be able to control foot motion. In addition, the ability of foot taping to control both height and width changes is clinically relevant given the 2008 paper by Vicenzino and associates in which a change in midfoot width from non-weight bearing to weight bearing was found to be one of four variables that were predictive of a successful treatment of patellofemoral pain using foot orthoses.29 As such, this finding is unique and adds additional information to the current understanding of the effect of taping of the foot. The increase in the width of the midfoot immediately after running 2 miles and then subsequently decreasing four hours later was seen with both taping procedures and was statistically significant. (Table 4 and Figure 4). Although further research is warranted, this slight increase in midfoot width immediately after exercise could be attributed to increased fluid within the foot as a result of the running. If this is the case, such stretching of the elastic tape could then rebound as the fluid is reduced.

Franettovich and colleagues15 found that anti-pronation taping using the reverse-6 method resulted in a reduction in electromyographic activity of the tibialis anterior and tibialis posterior muscles during walking. It is therefore possible that such a reduction in muscle activity following taping could result in increased fluid retention, which then increased the width of the midfoot. Certainly, additional research is warranted related to this finding. A reduction in muscle activity secondary to taping may have a deleterious effect if used over a long period of time.

The majority of the studies that have looked at the duration of the effect of LD taping on foot posture have used a brief bout of exercise, usually less than 20 minutes.7,18,20,30 Many of these studies have shown a relatively short-term effect (less than 20 minutes) from the tape. A systematic review in 2006 by Radford2 concluded that the increased arch height seen following application of the LD taping technique was no longer present following 10 to 20 minutes of exercise (jogging).8 Investigations using the “augmented LD” technique have demonstrated a more sustained change compared to the LD technique alone, but

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again, they have not looked at anything greater than 20 minutes of exercise.4,5,14 Because the current study looked at the effect of time as well as a bout of exercise on the duration of the change in foot posture following taping, it is difficult to compare the results of the current study with that of past research.

The results of the current study do indicate that although either taping procedure may be used to obtain an immediate change in the height and width of the medial longitudinal arch, however, the two taping procedures differed with respect to how long that effect lasted. The change in the height of the arch after using the MR6 technique was no longer significant after four hours of general activity. DAH with the MR6+LD procedure, on the other hand, was still significantly different from the pre-tape measurement at each time period throughout the day of testing. This finding indicates that augmenting the LD technique with the MR6 results in a more sustained change in DAH. In addition, the results of the current study indicate that the augmentation of the LD taping technique with the MR6 technique using elastic tape results in a more sustained effect, especially with respect to the change in the width of the midfoot.

It appears that although the LD taping technique is able to alter the posture of the foot, the change is primarily in the vertical direction since a greater change in the width of the midfoot seen when only the MR6 taping procedure was used. As such, it appears that if the goal of taping the foot is to increase the height of the arch, the MR6+LD procedure would be sufficient, however, if the objective is to decrease the width of the midfoot, the MR6 or the MR6+LD procedure would be effective. Such findings have clinical implications since previous research has identified arch height and mobility of the midfoot to be related to patellofemoral pain.29,31 Although the MR6 taping procedure alone resulted in the greatest decrease in the width of the medial longitudinal arch, combining both taping procedures demonstrated the ability to maintain the change throughout the day of testing. Additional research is certainly needed investigating the two taping methods used in the current study. This is especially true with regard to whether there is a difference between either procedure being able to reduce clinical symp-

toms of pain and dysfunction caused by excessive foot pronation and whether there is a minimal height or width change needed to reduce symptoms and improve function. In addition, there is also only anecdotal evidence that individuals prefer the elastic tape compared to inelastic tape because it is more comfortable and there is less skin irritation and blister formation. As such, future research should look at the influence of patient acceptance or preference on successful clinical outcomes.

CONCLUSION Based upon the results of this study, the MR6 taping technique using elastic tape may be applied alone or with the LD taping technique in order to alter the height and width of the medial longitudinal arch.

In addition, the changes seen in the width of the medial longitudinal arch remain statistically different from that produced immediately after applying the tape with either technique. The duration of the affected change is even more pronounced when the MR6 and LD taping procedures are combined.

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Vicenzino B, Collins N, Cleland JA, McPoil TG. A clinical prediction rule for identifying patients with patellofemoeral pain who are likely to benefit from foot orthoses: a preliminary determination. Br J Sports Med. 2008;(1):1–10. doi:10.1136/ bjsm.2008.052613.

Nolan D, Kennedy N. Effects of low-dye taping on plantar pressure pre and post exercise: an exploratory study. BMC Musculoskeletal Disorders.

2009;10(1):40. doi:10.1186/1471-2474-10-40.

Cornwall MW, McPoil TG. Relationship between static foot posture and foot mobility. J Foot Ankle Res. 2011;4(4):1–9. doi:10.1186/1757-1146-4-4.

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IJSPT

ORIGINAL RESEARCH

VALIDATION OF A NEW METHOD FOR ASSESSING SCAPULAR ANTERIOR-POSTERIOR TILT Jason S. Scibek, PhD, LAT, ATC1 Christopher R. Carcia, PhD, PT, SCS, OCS2

ABSTRACT Background: Electromagnetic tracking systems have enabled some investigators and clinicians to measure tri-planar scapular motion; yet, they are not practical and affordable options for all clinicians. Currently, the ability to affordably quantify scapular motion is limited to monitoring only the motion of scapular upward rotation, with use of a digital inclinometer.

Hypothesis/Purpose: The objective of this study was to determine the criterion-related validity of a modified digital inclinometer when used to measure the motion of scapular anterior-posterior (AP) tilt.

Materials & Methods: Thirteen volunteers, free from any history of shoulder injury, reported for a single testing session. Each subject underwent a brief shoulder and posture examination in order to confirm the absence of pathology. Subjects actively performed clinically relevant amounts of humeral elevation in the scapular plane while in a seated position. An electromagnetic tracking system (Ascension Technology, Burlington, VT) and a modified inclinometer (Pro 360, Baseline®, Fabrication Enterprises, White Plains, NY) were used to acquire scapular AP tilt over the same shoulder motions. Criterion-related validity was determined using Pearson Product Moment correlations.

Results: Correlation analyses revealed significant moderate to good associations (r = 0.63 to 0.86, p < 0.01) between scapular AP tilt measures obtained with a digital inclinometer and an electromagnetic tracking system.

Conclusions A modified digital inclinometer is a moderately valid device to use for the quantification of scapular AP tilt. Further study is warranted to establish reliability and to validate use of the device in patients with shoulder injury or pathology. The modified inclinometer expands the clinician’s ability to quantify scapular kinematic motion during the clinical evaluation and rehabilitation process.

Key Terms: inclinometer, scapula, scapular kinematics shoulder, validity Level of Evidence: Level 3

1

Department of Athletic Training, Duquesne University, Pittsburgh, PA, USA 2 Department of Physical Therapy, Duquesne University, Pittsburgh, PA, USA No conflicts of interests or financial biases exist for this study.

The study was approved by the Duquesne University Institutional Review Board (Protocol #09-11) This study was funded by the Pennsylvania Athletic Trainers’ Society (#G0900028).

CORRESPONDING AUTHOR Jason S. Scibek, PhD, LAT, ATC Chair, Associate Professor Department of Athletic Training, HLSB 119 Duquesne University Pittsburgh, PA 15282 (412)396-5960 E-mail: scibekj@duq.edu

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INTRODUCTION The use of electromagnetic tracking devices has allowed researchers and clinicians to obtain in-vivo measures of scapular motion, expanding clinical understanding of scapular tri-planar motion.1-3 In addition to gaining an understanding of how scapular rotations contribute to overall shoulder motion, investigators and clinicians are becoming more aware of the scapular movement patterns exhibited by various patients populations,4 including those with adhesive capsulitis,5,6 multi-directional instability,7 and rotator cuff pathologies,8-12 when performing scapular plane shoulder elevation. Patients with adhesive capsulitis appear to initiate scapular upward rotation earlier 5 and tend to exhibit greater amounts of upward rotation6 in comparison to healthy subjects.

Conversely, subjects with multidirectional instability seem to exhibit altered scapulohumeral rhythm,13 including reductions in scapular upward rotation and increases in scapular medial tilt.7,14 Evidence suggests that patients with rotator cuff pathology or shoulder imp-ingement tend to present with alterations in all three components of scapular motion, including reductions in scapular upward rotation, decreased posterior tilt and increased medial scapular rotation.8-10,15 Increases in scapular and clavicular elevation, scapular upward rotation and posterior tilting in impingement patients have also been noted; yet, it has been suggested these altered kinematics may be compensations for pain.16,17 Unfortunately, while this scapular kinematic data is available to clinicians and could be used to support clinical intervention, most clinicians are unable to monitor and quantify tri-planar scapular motions due to the cost and lack of accessibility to the necessary equipment.

Various attempts have been made to establish clinically accessible methods that are valid and reliable for qualitatively 18-21 and quantitatively 22-27 evaluating scapular kinematics. Many of the quantitative methods have addressed the scapula’s relative position, displacement and posture, and in doing so have not addressed the scapula’s three-dimensional orientation. Although techniques like the double square28,29 and the lateral scapular slide test25,27 have been used in clinically based studies, the validity and the clinical usefulness of these examination procedures is questionable.26, 30, 31 Few studies have presented clinically accessible means of quantifying scapular angular

orientation. 22,32 Sobush et al. established the validity and reliability of the Lennie test, which examined resting scapular upward rotation position.22 However, Johnson et al32 were the first to develop a reliable and valid means of quantifying scapular upward rotation using a modified digital inclinometer to measure the scapula’s angular orientation at varying degrees of humeral elevation. The inclinometer was deemed reliable and valid for assessing upward rotation in both healthy subjects and those with shoulder pathology, noting good to excellent validity (r = 0.59 – 0.92) when compared to measures obtained with an electromagnetic tracking system.32 The reliability and validity of other inclinometers have also been established for making similar upward rotation measures.33,34 Use of the inclinometer is dependent on the clinician’s ability to align the inclinometer with the spine of the scapula in order to measure scapular upward rotation associated with varying amounts of humeral elevation. The alignment results in the inclinometer being positioned relative to a perpendicular axis that is directed orthogonally to the scapula approximating the axis about which scapular upward and downward rotation occurs.32 Other authors 34-39 have also explored scapular upward rotation using this clinically useful technique in the shoulders of healthy individuals and symptomatic and asymptomatic overhead athletes.

Ludewig and Reynolds4 recently described the role that scapular anterior-posterior (AP) tilt plays in overall scapular function, its contributions to humeral elevation, and more specifically its connection to shoulder pathologies. The accessory contributions and variable nature of medial-lateral (ML) scapular tilt were also noted in the review. Presently, aside from the visually based observation studies designed to rate the orientation and angular motions of the scapula18-21,40 and those that assess overall shoulder girdle/scapular position30 there are no studies that specifically measure AP or ML tilt of the scapula. Unfortunately, without the use of an electromagnetic tracking device most clinicians lack the means to quantitatively assess these significant components of scapulothoracic function, most notably AP tilt. By expanding use of a gravity-dependent digital inclinometer to include measures of scapular AP tilt, the authors’ hope to enhance the evaluative capabilities for the shoulder, which will facilitate

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clinicians’ abilities to monitor the outcomes of their rehabilitative efforts relative to scapular neuromuscular control. While the reliability of the inclinometer to measure scapula AP tilt has been established,41 no efforts have been made to validate this instrument for measuring AP tilt. Therefore, the objective of this study was to establish the criterion-related validity of a modified digital inclinometer when used to measure the motion of scapular AP tilt. The authors’ hypothesized that a modified digital inclinometer would exhibit strong criterion-related validity when compared to measures obtained from an electromagnetic tracking system.

MATERIALS & METHODS Subjects A sample of thirteen, healthy college students (21.46 + 1.13 years; 1.76 + 0.11 meters; 76.19 + 12.57 kg; 8 males, 5 females; 11 right-handed, 2 left-handed) volunteered to participate in the study. Pilot data was collected as part of a separate study and a power analysis was performed using the free statistical package G*Power 342 to determine the sample size.

The study was powered to 80%, using effects sizes ranging from r = 0.76 - 0.85 and α = 0.05, resulting in a sample size of 13 participants. To be included subjects had to be between the ages of 18 and 40 years old, free from any previously diagnosed upper extremity, neck or back injury. Individuals were excluded if they 1) presented with any neurological conditions that may result in muscle weakness and consequent decreased upper extremity range of motion, including cervical disc disease or stenosis, stroke, or brachial plexus injury, 2) had experienced any trauma or injury to their dominant or non-dominant shoulder in the last 6 months, 3) had surgery involving the neck, back, or either upper extremity, 4) suffered from rheumatoid arthritis, and/or 5) were potentially pregnant. Individuals with allergies to tape adhesives were also excluded from participating in the study.

Subjects read and signed an informed consent document approved by the University’s Institutional Review Board prior to data collection. Subjects completed a questionnaire designed to ascertain demographic data and health history in order to ensure no history of neck, spine or upper extremity injury.

The primary investigator performed a brief physical screen in order to determine the presence of any current shoulder injury or pathology. The primary investigator was a certified athletic trainer with 14 years of clinical experience at the time of the study.

The screen involved measures of shoulder range of motion, strength, and a subset of evaluative special tests to ensure the absence of previous or current injury.43 Subjects presenting with no shoulder injury history, range of motion and strength measures that were consistent bilaterally, and the absence of pain and abnormal findings for the orthopedic special tests were included. Active and passive shoulder ranges of motion (flexion, abduction, medial/lateral rotation) were assessed using standard goniometric measurement techniques.44 A single trial was performed for each motion. Similarly, shoulder strength (flexion, abduction, medial/lateral rotation) was assessed using standard manual muscle testing techniques.45 A handheld dynamometer (ErgoFet 300, Hogan Health Industries, West Jordan, UT) was utilized to obtain strength measures for each muscle group. Two break tests were performed for each muscle group and the mean of the two trials was calculated for each muscle group strength assessment.

(Table 1) To help characterize the physical presentation of the subjects, each underwent a brief postural and scapular movement screen as described by Kibler et al.19 The position and orientation of the scapula was observed with subjects standing and when performing humeral elevation, starting with their hands at their sides and moving their arms overhead. Noteworthy scapular positions included 1) excessive superior placement or translation, 2) inferior angle prominence, 3) medial border prominence and/or normal scapular appearance.19 Although some subjects presented with dyskinetic scapular movement patterns, all shoulders were classified as non-pathologic due to the lack of previous or current shoulder injury. (Table 1) Instrumentation A digital inclinometer (Pro 360, Baseline®, Fabrication Enterprises, White Plains, NY) was used to assess scapular AP tilt during humeral elevation trials. A series of modifications were made to the inclinometer to make it suitable for measuring AP tilt. Specially

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Table 1. Subject demographic data and physical characteristics.

Demographics Age (years)

21.46 + 1.13

Height (meters)

1.76 + 0.11

Weight (kg)

76.18 + 12.57

Body Composition (%)

16.55 + 5.62

2

BMI (kg/m )

22.79 + 6.99

Gender

8 males, 5 females

Hand Dominance

11 right, 2 left

Scapula Posture

7 normal scapula posture 5 medial border prominence 1 inferior angle prominence

Range of Motion (deg) Active Flexion

Abduction

Lateral Rotation

Medial Rotation

Passive

D

o

176.85 + 6.23

179.85 + 0.55o

ND

176.54 + 7.05o

179.23 + 1.96o

D

179.31 + 1.70 o

179.85 + 0.38o

ND

179.31 + 1.70o

179.23 + 0.28o

D

107.15 + 7.71o

129.46 + 12.38o

ND

101.92 + 10.81o

117.54 + 11.45o

D

53.00 + 12.40o

61.38 + 13.54o

ND

56.15 + 9.01o

66.85 + 11.44o

Normalized Strength (%) Flexion Abduction Medial Rotation Lateral Rotation

D

19.29 + 4.80

ND

19.18 + 4.26

D

18.53 + 3.90

ND

17.93 + 4.72

D

17.25 + 4.43

ND

17.43 + 3.56

D

12.54 + 3.37

ND

12.72 + 2.39

Means and standard deviations are provided for each characteristic.

BMI=body mass index; D=dominant; ND=non-dominant. Strength measures were obtained using a hand held dynamometer (ErgoFet 300, Hogan Health Industries, West Jordan, UT). All strength measures were normalized to the body weight of the subject and are recorded as a percentage of body weight.

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designed wooden feet were used with the inclinometer in order to appropriately align the inclinometer with scapula bony landmarks. Each “foot” measured 5.3cm x 1.0cm x 1.0 cm and included a blunted end used to align the scapular bony landmarks. A custom-made plate measuring 7.0cm x 20.5cm (Lexan*, SABIC Innovative Plastics, Pittsfield, MA) was attached to the inclinometer, allowing for adjustable spacing of the “feet” (1 cm increments). (Figures 1A & B) Each “foot” was attached to a 3.5cm corner brace and affixed to the Lexan plate using standard hardware. The modifications allowed for alignment with a vertically oriented axis passing through the inter-

Figure 1. (A) Modified digital inclinometer, (B) Orientation of inclinometer relative to scapula. The digital inclinometer (Pro 360, Baseline®, Fabrication Enterprises, White Plains, NY) was oriented vertically, in plane with the dorsum of the scapula, and was aligned with the inferior angle of the scapula and the intersection of the scapular spine and medial border.

section of the spine and medial border of the scapula and the inferior angle of the scapula. Using palpation, the investigator was able to align the inclinometer with these two points (Figure 2). Strong intrarater reliability (ICC3,2 = 0.93 – 0.99) using this device was established for the primary investigator as part of a separate study.41 Three dimensional scapular kinematic data for validation of the digital inclinometer were collected using an electromagnetic tracking system (Ascension Technology, Burlington, VT), and Motion Monitor software (Innovative Sports Training, Chicago, IL). The system’s short-range transmitter was rigidly fixed to metal free scaffolding to minimize interference with the system. Three sensors were used to track motion of the trunk, humerus and scapula.

The trunk sensor was affixed to the subject’s cervical spine (proximal to the spinous process of C7) using double sided tape and reinforced with 1” athletic tape. The scapula sensor was mounted on the acromion process in a similar fashion; while the humeral sensor was strapped proximally on the humerus with the manufacturer provided strapping system. (Figure 3) Using twelve digitized landmarks, local anatomic and reference coordinate systems approved by the International Society of Biomechanics were

Figure 2. Scapular alignment points for the inclinometer.

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to minimize compensatory changes of the lower extremity and trunk, which could impact shoulder biomechanics. The subjects were asked to move their hands to selected points along the screen that corresponded to specific shoulder ranges of motion (rest, 30o, 45o, 60o, 90o, 120o) in the scapular plane.

Shoulder ranges of motion were monitored with a digital inclinometer and hand placement was marked on the screen with respect to the specific shoulder ranges of motion, to ensure repeatable arm placement throughout the data collection. Data collection occurred in the plane of the scapula. All testing involved the dominant shoulder.

Figure 3. Subject testing set up with the electromagnetic tracking system.

constructed in order to calculate position, orientation and displacement of the scapula and humerus.46 Kinematic data were collected at 100 Hz. The accuracy of the electromagnetic tracking system and the reliability of the testing procedures have been established for the laboratory in which this study was conducted and have been published previously.47 For system accuracy, the root mean squared error for linear position, angular orientation and linear displacement are 5.3mm, 0.23o, and 3.1mm, respectively in this laboratory. While values for linear displacement have not been provided by the manufacturer or in the literature, the position and orientation values documented by the laboratory are similar to previously reported values.48 The ICC (3,1) values for intrasession reliability ranged from 0.812 to 0.999 for glenohumeral motion (elevation, plane, rotation) and 0.983 to 0.999 for scapular motion (AP tilt, ML tilt, upward/downward rotation). Validation data using the tracking system in the laboratory suggested that the equipment is valid for capturing human motion (r = 0.85 to 0.99); however, the system routinely under-represented the amount of humeral elevation being achieved.47 Similar errors have been noted previously in the literature.49 Therefore, when reporting findings for this study, relative values as opposed to absolute values of motion were reported.

Patient Preparation and Data Collection Subjects were seated on a plastic stool one armâ&#x20AC;&#x2122;s length from a stationary screen. Subjects were seated

The electromagnetic sensors then were attached using double-sided tape and straps in order to secure the sensors to the subjects. After affixing the sensors, a separate sensor was used to digitize a series of 12 anatomical landmarks in order to create local anatomic and reference coordinate systems.46 The landmarks included, 1) spinous process of C7, 2) spinous process of T8, 3) spinous process of T12, 4) jugular notch of the sternum, 5) xiphoid process, 6) coracoid process, 7) AC joint, 8) posterolateral corner of the acromion, 9) inferior angle of the scapula, 10) intersection of medial border and spine of the scapula, 11) medial epicondyle and 12) lateral epicondyles of the humerus.

Testing order was randomized by arm position and was maintained for both inclinometer and electromagnetic tracking system measures. Subjects began with the dominant hand at his/her side and were then asked to move the hand to a selected position and to hold that position while kinematic data were acquired. Three trials were performed for each shoulder position with both the inclinometer and the tracking system (rest, 30o, 45o, 60o, 90o, 120o of humeral elevation). These shoulder positions were selected as they are commonly reported in the shoulder biomechanics literature. Additionally, a single anatomical position trial was captured with both instruments for use during data processing.

Each trial lasted 10-15 seconds, and subjects were provided with 5-10 seconds rest in between each trial and an additional one minute of rest in between each set of three trials. For inclinometer bony landmark orientation, the primary investigator relied on palpation to identify the position of the inferior

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angle, medial border and spine of the scapula for each trial. The primary investigator was responsible for all measures taken with the inclinometer, but was blinded while aligning the inclinometer. The inclinometer values were recorded by a laboratory assistant after each trial and the inclinometer was repositioned for each trial. The primary investigator was also blinded to the electromagnetic tracking system data with respect to scapula angular values during each testing session. All trials were completed first with the electromagnetic tracking system, and then followed by the digital inclinometer. A total of six trials were completed at each shoulder position; three using the electromagnetic tracking system and three with the inclinometer. Kinematic data collection using both measurement systems did not occur concurrently within each trial due to the documented distortion of the electromagnetic field caused by the introduction of metal in the testing environment.50-52 Data processing Humeral and scapular kinematics were computed from the MotionStar sensor data using the Euler angle sequences approved by the ISB.46 A Butterworth filter with a cutoff frequency of 8 Hz was used to smooth the data.53 Tracings and values associated with humeral elevation positions were observed visually in Motion Monitor to confirm stability of the data.

Stability of the data was defined by fluctuations of < 1o for a minimum of 50 consecutive data points (0.5 seconds). The Motion Monitor processed data was then exported into Excel (Microsoft Corporation, Redman, WA) where means for the humeral and scapular kinematics were calculated. The scapular kinematic means were then used for the validity analyses.

The assessment of criterion-related validity was based upon relative values obtained from the electromagnetic tracking system and inclinometer as opposed to absolute measurements. To compute relative scapular values or the change in scapular orientation from baseline or anatomic position, the scapular values obtained during the single anatomic position trial were subtracted from the values observed at rest, 30⬚, 45⬚, 60⬚, 90⬚, 120⬚ of humeral elevation for both measurement devices during each of the three trials. The means of the three trials for each subject at each position of elevation were then calculated and used during data analysis. Using this

approach to quantify scapular orientation enabled the calculation of the relative change in scapular orientation and accounted for differences in the measurement devices. While the scapular orientations obtained with the inclinometer are based upon the inclinometer’s position and gravity, orientations of the scapula obtained with the electromagnetic tracking system are based upon the relative position of the scapula with respect to the thorax.

Data analysis Means and standard deviations were calculated for the demographic data. Criterion-related validity was assessed via Pearson Product Moment correlation (r) analyses where orientation data of the inclinometer and the electromagnetic tracking system were compared. Coefficients of determination (r2) were used to evaluate the clinical meaningfulness of the relationships. The upper and lower limits of agreement (+ 1.96 standard deviation) were calculated for the paired mean differences (inclinometer vs. electromagnetic tracking system) in order to examine the relationship between measurement error and the mean of the two tests.54 Additionally, intrarater reliability was calculated for the data set using intraclass correlation coeffecients (ICC3,1). SPSS version 17.0 was used for the statistical analyses and an α = 0.05 was used for all statistical analyses.

RESULTS The assessment of intrarater reliability for the primary investigator revealed strong repeatability for this data set. Within session reliability at each humeral elevation was found to be excellent with ICC3,1 ranging from 0.97 to 0.99.

The criterion-related validity analysis revealed significant moderate to good correlations (r = 0.63 to 0.86, p < 0.01) across several combinations of humeral elevation angles consistent with the shoulder biomechanics literature. (Table 2) The validity measures were considered to be moderate to good based upon the range described by Portney and Watkins where 0.00 to 0.25 represents no or little relationship; 0.25 to 0.50 represents a fair relationship; 0.50 to 0.75 signifies a moderate to good; and values > 0.75 considered good to excellent55. An examination of the slope coefficients revealed slopes that were equal to 0.52 + 0.06. The coefficients of determination (r2 = 0.40 to

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Table 2. Comparisons of anterior-posterior tilt measures between a modiďŹ ed digital inclinometer and electromagnetic tracking system.

Humeral Elevations Rest, 30o, 45o, 60o, 90o, 120o Rest, 30o, 60o, 90o, 120o Rest, 60o, 90o, 120o Rest, 90o, 120o Rest, 120o

r*

Slope

Intercept

MD

0.63 0.67 0.69 0.79 0.86

0.46 0.48 0.52 0.57 0.57

0.41 0.48 0.32 0.66 0.70

(degrees) 4.45 4.32 4.75 3.92 3.66

95% Limits of Agreement -16.79, 7.90 -16.66, 8.03 -17.09, 7.58 -15.57, 7.72 -15.85, 8.52

MD=the mean difference between inclinometer and electromagnetic tracking measures, reported in degrees; r=correlation coefficient. *All correlations were significant at the p < 0.01 level.

0.74) revealed that 40-74% of the error variance can be accounted for by common factors involving the two devices. Measures of scapular AP tilt obtained with the inclinometer were consistently greater than those obtained with the electromagnetic tracking system.

The inclinometer and electromagnetic tracking system AP tilt values reflect a gradual increase in scapular posterior tilt as greater amounts of humeral elevation are achieved. (Table 3) The limits of agreement analysis indicated that the mean of the paired differences for the two devices ranged from 3.67o + 6.21o to 4.75o + 6.29o when looking across all humeral elevation angles for each combination of humeral elevations. The 95% upper and lower limits of agreement resulted in a +12o envelope with respect mean differences for each combination of humeral elevations. (Figure 4) Although one subjectâ&#x20AC;&#x2122;s data

fell below the lower limit of agreement, the analysis revealed moderate agreement between the two devices as data from all other subjects routinely fell within the limits of agreement.

DISCUSSION The comparison between an electromagnetic tracking system and a modified digital inclinometer revealed moderate to good criterion-related validity for the measurement of scapular AP tilt using the inclinometer. Further analysis also demonstrated that this novel device was able to account for 40%-74% of the error variance between devices, which was also reflected in the limits of agreement assessment. Although some of the current statistical findings were not as strong as those identified for use of the modified digital inclinometer for measuring scapular upward rotation,32 the results are valuable as they reflect an initial attempt at establishing an affordable and clinically viable means of assessing scapular AP tilt.

The current effort to establish the inclinometer as a valid tool for assessing scapular AP tilt comes at a time when considerable emphasis continues to be placed on the importance of understanding triplanar scapular kinematics and their relationships with shoulder pathologies.4 During normal humeral elevation a combination of scapular upward rotation, posterior tilt, and lateral rotation occur.3, 4 It has been

Table 3. Anatomical Neutral and Relative Scapular Anterior-Posterior Orientations.

Active Humeral Elevation Position

Digital Inclinometer Measures

Anatomic Neutral 68.68o

Relative

Electromagnetic Tracking System Measures

Anatomic Neutral -11.75o

Relative

0.00o 0.00o Rest o o 4.45 1.88o 30 o o 7.38 2.29o 45 o o 9.98 2.75o 60 o o 12.00 7.56o 90 20.06o 12.73o 120o Note: Values reflect the mean relative change in scapular AP tilt for all subjects at each humeral elevation position from anatomic neutral for the digital inclinometer and electromagnetic tracking system. The negative anatomic neutral trial for the electromagnetic tracking system reflects an anteriorly tilted scapula. Increases in relative values reflect movement of the scapula to a more posteriorly tilted orientation.

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Figure 4. Bland & Altman plot depicting the 95% limits of agreement between devices for scapular AP tilt measures for the humeral elevation positions rest, 30⬚, 45⬚, 60⬚, 90⬚ & 120⬚.

suggested that limitations in these scapular motions can alter glenohumeral joint kinematics and stability, and ultimately contribute to the development of shoulder pathologies.4 Although the involvement of scapular AP tilt is less apparent in patients presenting with multidirectional instability and adhesive capsulitis, studies have noted relative reductions in posterior tilt in patients presenting with shoulder impingement during assessments of humeral elevation.8-10, 15 In these reports the noted differences were relatively small in comparison to healthy control subjects; however, given the limited space beneath the coracoacromial arch, small variations in scapular kinematics could place the subacromial structures at an increased risk of injury. Interestingly, McClure et al17 identified increases in scapular posterior tilt and upward rotation when assessing patients with subacromial impingement. Laudner et al16 also noted increases of posterior tilt and scapular elevation; however, this was observed in patients with internal impingement.

Regardless, Laudner et al16 and McClure et al17 suggested that these increases in scapular motion were compensatory adjustments made to reduce soft tissue loading associated with the respective forms of impingement. Having validated the inclinometer for use when measuring scapular AP tilt in the present study, clinicians will now be able to readily compare patient findings with the data from these clinicallybased studies and better direct rehabilitation efforts.

The data revealed moderate to good criterion-related validity when analyzing the data across all subjects, using selected combinations of commonly reported positions of humeral elevation. While an electromagnetic tracking system does allow for static and

dynamic in-vivo scapular kinematic assessment, a static assessment appeared to be more prudent given the manner in which the inclinometer had been modified and would be used clinically. Furthermore, previous work by Johnson et al32 found that the strengths of the relationships between the inclinometer and electromagnetic tracking system were stronger when comparing to the static versus the dynamic electromagnetic tracking system measures. Overall, the slope coefficients associated with the observed relationships suggest positive relationships between measures taken with both devices.

The slopes of the humeral elevation combinations fell within the range of 0.46 to 0.57, suggesting that as the -modified inclinometer detected 1o of change in scapular AP tilt, the electromagnetic tracking system recorded approximately a 0.50o increase.

Although these findings are lower than the findings reported by Johnson et al32, they are consistent with an electromagnetic tracking system validation study that noted under-reporting of shoulder joint range of motion angles when comparing tracking system data with standard goniometric measures.47 Although the mean differences between the devices were higher than desired, the consistency of the slopes, slope intercepts and mean differences can be attributed to systematic differences. The authors would suggest that three factors: differences in measurement systems, palpation error, and morphological variability, may have contributed to the variations in these values. The shear comparison between a 2-dimensional, gravity-dependent measurement system, generating Euclidean angles with an electromagnetic tracking system that results in Euler angle data may have consistently contributed to the differences observed between the measurement devices. Similarly, alignment of the inclinometer was based upon the inferior angle and scapular spine, while the tracking system data for the scapula was obtained by placing a sensor on the acromion process and relied on a local coordinate system whose origin was the posterolateral aspect of the acromion.46 While both systems are able to generate angular measures, the basis of their calculations may have resulted in some inherent discrepancies in the actual angular measurements. The role of palpation and landmark identification has been examined on multiple fronts as it relates to discrepancies

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in shoulder kinematic descriptions.51, 52, 56, 57 Recent work involving computational modeling has shown that shoulder kinematic descriptions are sensitive to select anatomical landmarks and that uncertainty or error in landmark identification can introduce variability into these shoulder kinematic descriptions.57 Based upon in-vivo data collected using an electromagnetic tracking system, de Groot56 noted that palpation errors result in approximately 2o kinematic description inaccuracy. However, de Groot also suggests that a greater amount of variability and error is introduced into the description due to inter-subject morphology.56 Others suggest that movement characteristic, subject demographics and the interplay between skin-based sensors and soft tissue artifact may warrant consideration relative to electromagnetic tracking system accuracy.49,58 While there may be a design limitation in the inclinometer that does not sufficiently control for morphological variability and that some inherent error in our “gold standard” exists, having one investigator responsible for all study-related palpations likely helped to minimize systematic error in the kinematic descriptions that could be attributed to both palpation error and intersubject morphology.

The data processing and analysis approach used to assess scapular AP tilt was unique when compared to the approach that others32,33 have used to quantify scapular kinematics. Electromagnetic tracking systems have been established as the gold standard for scapular kinematic assessment; yet, the authors’ experience would suggest that examining these relationships would be best served by examining relative scapular orientations over an arc of select humeral elevations as opposed to absolute scapular orientations at the select points of humeral elevation.47 Therefore, the decision was made to examine the ability of the inclinometer to track scapular AP tilt across the selected ranges of humeral elevations.

While for clinicians it is important to examine how segment or joint motion may change at selected intervals, it is equally important to examine the extent to which the scapula would tilt over an arc of humeral elevation. Likewise, clinicians evaluate discrete skills and comprehensive functional abilities in patients, and although they often attempt to address scapular kinematics at discrete points of humeral elevation, realistically during functional

activities the scapula rarely remains fixed. Ultimately, although this study incorporated a unique data analysis approach, the study findings support the use of this clinically available and novel tool/ technique for measuring scapular AP tilt.

When considering the values obtained for scapular AP tilt, the measures are consistent with AP tilt values described in previous studies.3,59,60 Although strong relationships were observed between measurements from the inclinometer and the tracking system, additional analyses indicated that further refinement of the inclinometer may be necessary to enhance the agreement between devices. The coefficients of determination revealed that depending on the combination of humeral elevation angles, 40-74% of the error variance can be accounted for by factors common to both devices. An assessment of the limits of agreement between the devices further exposed the disparity between the devices as it relates to comparably quantifying scapular AP tilt.

Again, inaccuracies in the tracking system’s ability to assess shoulder kinematics, the influence of palpation error, and certainly morphological variability could all have contributed to the noted error observed in both systems. Variability associated with scapular medial rotation3, 61 may have contributed to some of the weaker findings as well, particularly during early phases of humeral elevation. It is unclear whether similar issues may have been present during validation of the digital inclinometer for use with scapular upward rotation as this data for the lower ranges of humeral elevation were not presented.

Given the noted differences and confounding factors one design modification to consider could include use of a third foot to facilitate inclinometer alignment within the scapular plane. Johnson et al32 used a bubble level to minimize axial rotation of the inclinometer. Unfortunately, given the required positioning of the inclinometer to obtain scapular AP tilt, use of a bubble level was inappropriate. While the primary investigator did attempt to keep the base of the inclinometer oriented with the plane of the scapula during testing, the addition of a third contact point on the scapula may improve inclinometer orientation relative to the scapular plane. Given inter-subject morphological variability and the displacement of the inferior angles as the scapula achieves greater upward rotation during humeral elevation, a third

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contact point may enhance the accuracy and precision of scapular AP tilt measures.

One of the limitations of the current study was that it did not include subjects with shoulder pathologies, limiting the generalizability of our validity findings.

To fully elucidate the usefulness of the inclinometer in patients with shoulder pathologies additional validation studies are necessary. A comparison between subjects with and without scapular dyskinesis may also be useful. Although many claim a connection between scapular dyskinesis and shoulder pathology, few have been able to establish this relationship.

While some subjects were identified as demonstrating dyskinetic scapular movement patterns using a validated instrument,19 the design of the present study was not appropriate to address this question. Since the initiation of our study Uhl et al21 and Ellenbecker et al40 have examined the validity and reliability of the dyskinesis evaluation system described by Kibler et al,19 while others have established the reliability and validity of an entirely new dyskinesis assessment scheme.18,20 Any attempts to determine the usefulness of the inclinometer in assessing subjects with dyskinesis should take the evolution of these dyskinesis assessment pieces into consideration. Furthermore, although the large limits of agreement envelopes can be partially attributed to differences between measurement devices and a small sample size, further refinement of the device should be considered.

CONCLUSION The findings of the current study suggest that a modified digital inclinometer is a moderately valid instrument to use when attempting to quantify scapular AP tilt. The current study represents the first to attempt to validate the use of this instrument as a clinically accessible and affordable means of quantifying scapular AP tilt. Expanding the exploration of the validity and reliability of this instrument to measure AP tilt in a patient population is critical.

However, the authorsâ&#x20AC;&#x2122; believe that further work in this area will ultimately provide clinicians with an accessible means of quantifying scapular motion both during clinical evaluations and throughout the injury rehabilitation process. Clinicians will when then have another means by which they can monitor and document patient progress with respect to scapular kinematics.

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15. Lin J-j, Hanten WP, Olson SL, et al. Functional activity characteristics of individuals with shoulder dysfunctions. J Electromyog Kinesiol. 2005;15:5769-586.

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25. Koslow PA, Prosser LA, Strony GA, et al. Specificity of the lateral scapular slide test in asymptomatic competitive athletes. J Orthop Sports Phys Ther.

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27. Odom CJ, Taylor AB, Hurd CE, et al. Measurement of scapular asymmetry and assessment of shoulder dysfunction using the lateral scapular slide test: A reliability and validity study. Phys Ther.

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28. Kluemper M, Uhl T, Hazelrigg H. Effect of stretching and strengthening shoulder muscles on forward shoulder posture in competitive swimmers.

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29. Laudner KG, Moline MT, Meister K. The relationship between forward scapular posture and posterior shoulder tightness among baseball players. Am J Sports Med. 2010;38(10):2106-2112.

30. Peterson DE, Blankenship KR, Robb JB, et al.

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31. Nijs J, Roussel N, Vermeulen K, et al. Scapular positioning in patients with shoulder pain: A study examining the reliability and clinical importance of 3 clinical tests. Arch Phys Med Rehabil. 2005;86:13491355.

32. Johnson MP, McClure PW, Karduna AR. New method to assess scapular upward rotation in subjects with shoulder pathology. J Orthop Sports Phys Ther.

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33. Tucker WS, Ingram RL. Reliability and validity of measuring scapular upward rotation using an electrical inclinometer. J Electromyogr Kinesiol.

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34. Watson L, Balster S, Finch C, et al. Measurement of scapula upward rotation: a reliable clinical procedure. Br J Sports Med. 2005;39:599-603.

35. Borsa PA, Timmons MK, Sauers EL. Scapularpositioning patterns during humeral elevation in unimpaired shoulders. J Athl Train. 2003;38(1):12-17.

36. Su KPS, Johnson MP, Gracely EJ, et al. Scapular rotation in swimmers with and without impingement syndrome: Practice effects. Med Sci Sports Exerc. 2004;36(7):1117-1123.

37. Laudner KG, Stanek JM, Meister K. Differences in scapular upward rotation between baseball pitchers and position players. Am J Sports Med. 2007;35(12):2091-2095.

38. Witwer A, Sauers EL. Clinical measures of shoulder mobility in college water-polo players. J Sport Rehabil. 2006;15:45-57.

39. Thomas SJ, Swanik KA, Swanik C, et al.

Glenohumeral rotation and scapular position adaptations after a single high school female sports season. J Athl Train. 2009;44(3):230-237.

40. Ellenbecker TS, Kibler WB, Bailie DS, et al.

Reliability of scapular classification in examination of professional baseball players. Clin Orthop Relat Res. 2012;47:1540-1544.

41. Scibek J, Gatti J, Carcia C. Establishing a reliable method of measuring scapular anterior-posterior tilt.

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42. Faul F, Erdfelder E, Lang A-G, et al. G*Power 3: A flexible statistical power analysis program for the social, behavioral, and biomedical sciences. Behavior Research Methods. 2007;39(2):175-191.

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43. Richards RR, An K-N, Bigliani LU, et al. A standardized method for the assessment of shoulder function. J Shoulder Elbow Surg. 1994;3(6):347-352.

44. Starkey C, Brown SD, Ryan J. Examination of orthopedic and athletic injuries. 3rd ed. Philadelphia: FA Davis; 2010.

45. Hislop HJ, Montgomery J. Daniel’s and Worthingham’s Muscle Testing: Techniques of Manual Examination. 8th ed. St. Louis, MO: Saunders; 2007.

46. Wu G, van der Helm FC, Veeger H, et al. ISB recommendation on definition of joint coordinate systems of various joints for the reporting of human joint motion - Part II: shoulder, elbow, wrist and hand. J Biomech. 2005;38:981-992.

47. Scibek JS, Carcia CR. Validation and repeatability of a shoulder biomechanics data collection methodology and instrumentation J Appl Biomech.

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Dynamic error analysis of Ascension’s Flock of Birds(TM) electromagnetic tracking device using a pendulum model. J Appl Biomech. 2002;18:171-179.

49. Ludewig PM, Cook TM, Shields RK. Comparison of surface sensor and bone-fixed measurement of humeral motion. J Appl Biomech. 2002;18:163-170.

50. LaScalza S, Arico J, Hughes R. Effect of metal and sampling rate on accuracy of Flock of Birds electromagnetic tracking system. J Biomech.

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51. Meskers CGM, Fraterman H, Van der Helm FCT, et al. Calibration of the “Flock of Birds” electromagnetic tracking device and its application in shoulder motion studies. J Biomech. 1999;32:629-633.

a six-degree-of-freedom electromagnetic tracking device. Clin Biomech. 1998;13:280-292.

53. Yu B, Gabriel D, Noble L, et al. Estimate of the optimum cutoff frequency for the Butterworth low-pass digital filter. J Appl Biomech. 1999;15(3):318329.

54. Bland JM, Altman DG. Statistical methods for assessing agreement between two methods of clinical measurement. Lancet. 1986;1:307-310.

55. Portney L, Watkins M. Foundations of Clinical Research: Application to Practice. 2nd ed. Upper Saddle River, NJ: Prentice Hall Health; 2000.

56. de Groot J. The variability of shoulder motions recorded by means of palpation. Clin Biomech.

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57. Langenderfer JE, Rullkoetter PJ, Mell AG, et al. A multi-subject evaluation of uncertainty in anatomical landmark location on shoulder kinematic description. Comp Meth Biomech Biomed Engineer.

2008;12(2):211-216 58. Karduna AR, McClure PW, Michner LA, et al.

Dynamic measurements of three-dimensional scapular kinematics: A validation study. J Biomech Eng. 2001;123:184-190.

59. Myers JB, Laudner KG, Pasquale MR, et al. Scapular position and orientation in throwing athletes.

2005;33(2):263-271.

60. Oyama S, Myers JB, Wassinger CA, et al.

Asymmetric resting scapular posture in healthy overhead athletes. J Athl Train. 2008;43(6):565-570.

61. Ludewig PM, Phadke V, Braman JP, et al. Motion of the shoulder complex during multiplanar humeral elevation. J Bone Joint Surg. 2009;91-A(2):378-389.

52. Meskers CGM, Vermeulen HM, de Groot JH, et al.

3D shoulder position measurements using

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IJSPT

ORIGINAL RESEARCH

THE RELATIONSHIP BETWEEN GLENOHUMERAL JOINT TOTAL ROTATIONAL RANGE OF MOTION AND THE FUNCTIONAL MOVEMENT SCREEN™ SHOULDER MOBILITY TEST Peter A. Sprague, PT, DPT, OCS1 G. Monique Mokha, PhD, ATC, LAT, CSCS1 Dustin R. Gatens, MS, ATC, LAT1 Rudy Rodriguez, Jr. ATC, LAT1

ABSTRACT Purpose/Background: Side to side asymmetry in glenohumeral joint rotation correlates with injury risk in overhead athletes. The purpose of the current study was to identify the relationship between side-to-side asymmetries in glenohumeral joint total rotational range of motion and shoulder mobility test scores from the Functional Movement Screen™ in collegiate overhead athletes.

The authors hypothesized that asymmetries of > 10⬚ in glenohumeral total rotation would not be associated with asymmetrical findings in the Functional Movement Screen™ (FMS) shoulder mobility test.

Methods: Passive glenohumeral total rotational range of motion and the shoulder mobility test of the FMS were measured during pre-participation examinations in 121 NCAA male and female Division II collegiate overhead athletes from varied sports. Passive shoulder range of motion was measured in supine at 90⬚ of abduction, with the humerus in the scapular plane using two measurers and a bubble goniometer. A Pearson Chi-square analysis, p<.05 was used to associate the presence of asymmetries in glenohumeral joint rotation and in the FMS shoulder mobility test in each subject.

Results: 40/114 (35.1%) athletes demonstrated asymmetries in total glenohumeral rotation. 45/114 (39.5%) athletes demonstrated asymmetries in the shoulder mobility test. Only 17 of the 45 subjects who demonstrated asymmetry on the shoulder mobility test also demonstrated glenohumeral joint rotation differences of > 10⬚. Athletes with asymmetries in rotation of > 10⬚ were not any more likely to have asymmetries identified in the shoulder mobility test (95% CI=.555-2.658, P=.627).

Conclusions Glenohumeral joint range of motion is one of multiple contributors to performance on the FMS shoulder mobility test, and alone, did not appear to influence results. The FMS shoulder mobility test should not be used alone as a means of identifying clinically meaningful differences of shoulder mobility in the overhead athlete. Clinicians working with overhead athletes may consider using both assessments as a complete screening tool for injury prevention measures.

Level of Evidence: Level 3 Key Words: functional movement asymmetry, Functional Movement ScreenTM, glenohumeral joint rotation, overhead athlete

1

Nova Southeastern University, Davie, FL, USA

No funding was received for this work.

This research was approved by Nova Southeastern University’s Internal Review Board

CORRESPONDING AUTHOR Peter A. Sprague, PT, DPT, OCS Nova Southeastern University- College of Osteopathic Medicine Sports Medicine Department Osteopathic Principles and Practice Department Davie, FL E-mail: Ps831@nova.edu

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INTRODUCTION Upper extremity injuries in the overhead athlete are prevalent in competitive sports, accounting for approximately 20% of all injuries in NCAA athletes across sports and up to 45% of all injuries in baseball.1-3 Differences in dominant versus non-dominant glenohumeral (GH) joint rotation in overhead athletes have been identified in the literature.4-8 These side to side differences in glenohumeral joint total rotational range of motion (TRROM), or the total arc of external rotation plus internal rotation, have been linked to upper extremity injury.9-14 Burkhart and Morgan9 reported a significant loss of internal rotation in symptomatic throwing shoulders of 124 baseball pitchers with type II SLAP lesions confirmed by arthroscopy. Wilk et al14 found a 2.5 times greater likelihood of injury in professional baseball pitchers who had greater than a 5âŹ&#x161; deficit in TRROM of the dominant versus non-dominant shoulder. Garrison et al12 showed that baseball players who suffered an ulnar collateral ligament tear exhibited significantly greater deficits in TRROM of the injured arm than matched controls of healthy baseball players.

to identify increased injury risk in professional athletes with findings of an asymmetrical movement pattern on individual tests performed within the screen.28 One of the seven functional movements examined in the FMS is the shoulder mobility test.

This test requires the subject to simultaneously reach one hand behind the back (internally rotate) and the other hand behind the head (externally rotate), bringing the hands as close together as possible in the thoracic region. (Figure 1) This type of reaching test has been described as a tool that measures GH joint mobility through functional shoulder movements.31,32 It has been suggested that impaired movement within the test may be indicative of more than just GH joint range of motion limitations.33 An understanding of the multi-variate contributors to movement dysfunctions associated with this test will provide clinicians with information that may guide choices for effective and specific injury prevention interventions.

These differences in rotational motion of the GH joint have been attributed to changes in bony morphology of the humeral head and glenoid that occur during the participation in overhead sports through musculoskeletal development.15-21 At birth, humans demonstrate a large amount of humeral retroversion. Throughout normal development, the humerus slowly becomes less retroverted, approaching normal humeral version, with individualsâ&#x20AC;&#x2122; demonstrating equal internal rotation and external rotation by the time the epiphyseal plates close.16 The repetitive torsional strains placed upon the humeral head by throwing during development have been implicated in keeping the humeral head in a more retroverted position.17,20 The retroverted position of the humerus influences the total arc of motion toward greater external rotation without changing the total amount of available motion.22 Recently, the use of screening tools has been recommended to examine active populations for deficiencies in fundamental movements in order to identify athletes who have a higher likelihood of incurring an athletic injury.23-30 The Functional Movement ScreenTM (FMS) is one such tool that has been shown

Figure 1. The FMS shoulder rotation test. Note the position of the ďŹ sts, which determines the score on this FMS test.

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Relatively small differences (>5⬚) in dominant versus non-dominant GH rotational range of motion have been suggested to be clinically relevant and have been shown to result in a greater likelihood of injury.14,34 The shoulder mobility test in the FMS may not be sensitive enough to identify these smaller rotational differences. To the authors’ knowledge, results of the FMS shoulder mobility test have not been examined with regard to measurements of total rotational range of motion of the GH joint. Therefore, the purpose of this study was to determine if the presence of an asymmetry of more than 10⬚ in TRROM could predict an asymmetry in the FMS shoulder mobility test in a group of intercollegiate overhead athletes. The authors hypothesized that overhead athletes with a side to side GH TRROM asymmetry would not be any more likely to demonstrate an asymmetry in side to side FMS shoulder mobility test scores.

METHODS This research was an observational cohort design.

GH joint TRROM and the FMS shoulder mobility test were measured during pre-participation examinations in 114 NCAA Division II collegiate athletes. Athletes were tested from the sports of baseball (n=34), softball (n=17), volleyball (n=10), men’s swimming (n=23), women’s swimming (n=20), and women’s tennis (n=10). Overhead athletes were chosen for this study because of the well-documented side-to-side differences in GH joint rotational ROM commonly found in this population.4-10,22 All testing was performed as part of the pre-participation examination process and all tests were performed on the same day for all sports.

Bilateral passive TRROM measures were performed on all subjects using a two-measurer method and a bubble goniometer. (Figure 2) The left shoulders were always measured first out of convenience. The two measurer method with scapular stabilization, described by Wilk et al35 to have the best reliability among several measurement methods of GH rotation, was used for measuring internal rotation.36 Passive internal and external rotation were measured on each arm in order to identify the total arc of rotational range of motion of the GH joint. Measurements were taken with the shoulder in 90⬚ of abduction and in the plane of the glenoid using a bubble goniometer.

Examiner one (PS) palpated the coracoid process

Figure 2. Two-measurer method of measuring passive glenohumeral internal rotation, using a bubble goniometer.

while passively moving the humerus to end range internal rotation. The measurement was taken by examiner two (RR) when movement of the coracoid first occurred and an endfeel was perceived, indicating the end of available passive glenohumeral joint motion and the beginning of scapular motion.

External rotation was measured using palpation to detect movement of the scapula in order to identify the end of glenohumeral external rotation passive range of motion.36,37 (Figure 3). All measurements of TRROM were performed by the same two examiners.

Examiner one had 21 years of experience in orthopaedic physical therapy practice and extensive experience working with post-surgical throwers, using

Figure 2. Two-measurer method of measuring passive glenohumeral internal rotation, using a bubble goniometer.

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this method of measurement for range of motion examination and re-examination. Examiner two has five years of experience as a certified athletic trainer working with collegiate and professional athletes.

FMS shoulder mobility test measures were taken prior to or following TRROM measures, with a random assignment of measurement order. FMS shoulder mobility test measures were taken by an athletic trainer certified in FMS testing. All measures for all subjects were taken without warm-up or following any physical activity that day. The FMS shoulder mobility test was performed as described by Cook.33 The subject’s hand length is measured from the joint line of the wrist to the tip of the third digit. The subject is then asked to reach one arm overhead and down their thoracic region while reaching the contralateral upper extremity behind and up their back, attempting to place their hands, closed in fists, as close together as possible. A distance between hands in this position less than the measured hand length is considered a score of “3”. A distance between one hand length and one and one-half hand lengths is considered a score of “2”, and a distance greater than one and one-half hand lengths is given a score of “1”. If pain is felt during the test, a score of zero is given. After performing the test, the subjects perform a clearing test designed to test for pain provocation. If pain is reported with the clearing test, a score of zero is also given. The side of the overhead hand is recorded as the reference side.

Scores that are unequal between right and left represent an asymmetry in this test. Subjects were categorized as either symmetrical or asymmetrical on the shoulder mobility test based upon their scores. This study was approved by the Internal Review Board at Nova Southeastern University.

STATISTICAL METHODS For each subject, the presence of an asymmetry or absence of an asymmetry on each of the variables was defined. For TRROM, a side-to-side difference of greater than 10⬚ was used to define the presence of an asymmetry. This threshold was chosen based upon previous results in the literature defining normal amounts of asymmetry in side to side TRROM in overhead athletes,4-7 the amounts of rotation associated with bony morphological changes in the overhead athlete,19,21 and measurement error associated with standard goniometry43 and use of a bubble level

on a goniometer.35 A Pearson Chi-square analysis, p<.05 was used to compare the presence or absence of asymmetries in TRROM and FMS shoulder mobility test in each subject tested.

RESULTS 114 athletes (male=57, female=57), ages 18-21, from 6 different sports that require overhead activity participated in this study. (Table 1) Forty 114 (35.1%) of athletes demonstrated asymmetries in glenohumeral joint TTROM while 45/114 (39.5%) athletes showed asymmetries in their FMS shoulder mobility test. Of the latter 45 athletes, 17 were measured as having GH joint TRROM differences of > 10⬚ (17.76⬚ + 5.27⬚). There were 23 athletes who had mean differences in glenohumeral joint TTROM (16.12⬚ + 5.13⬚) but no asymmetries in FMS shoulder mobility scores. These results are presented in Table 2. Results of the Pearson Chi-Square analysis showed that overhead throwing athletes with asymmetries in TTROM were not any more likely to have an asymmetry in FMS shoulder mobility test score, χ2 (1, N=114)=0.236, p>.05, (95% CI=.555-2.658, P=.627). Statistical results are presented in Table 3.

Table 1. Subjects by Sport, and age distribution Sport Baseball Swimming So ball Volleyball Tennis Age range (years)

Men Subjects (n=57) 34 23

18-21

Women Subjects (n=57) 20 17 10 10 18-21

Table 2. Descriptive statistics for glenohumeral TTROM and FMS shoulder mobility measures

FMS Shoulder mobility Asymmetry No Yes Total

Glenohumeral TTROM Total Asymmetry No Yes 46 23 69 28 17 45 74 40 114

Table 3. Association between asymmetries in glenohumeral TTROM and FMS shoulder mobility scores Variable Glenohumeral TTROM

Variable Range >100

N 45

<100

69

OR 1.214 (0.555 – 2.658) 1.00

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P .627 -

DISCUSSION Asymmetry in GH joint TRROM in overhead athletes is well documented. Differences in rotational range of motion of the GH joints in dominant versus non-dominant upper extremities have been linked to shoulder and elbow injuries in overhead athletes.9-14 Clinically meaningful differences in GH TRROM are small. Wilk14 found that greater than a 5⬚ difference in the total arc of rotational motion resulted in a 2.5 times greater likelihood of injury in professional baseball pitchers. It has been recently proposed that a TRROM deficit of > 5⬚ in overhead athletes be defined as pathologic glenohumeral internal rotation deficit, or p-GIRD.34 According to the current findings, these small differences are not detectable when using the FMS shoulder mobility test. Another consideration regarding the relationship of TRROM of the glenohumeral joint to injury is the amount of total motion available in the dominant arm. Wilk14 found that 78% of all injuries documented in their study exhibited a TRROM > 176⬚. They hypothesized that too much mobility of the glenohumeral joint may place excessive demands on the dynamic and static stabilizers of the glenohumeral and scapulothoracic joints. Accurate measurements of isolated GH joint mobility are required in order to identify athletes that fall outside of these specific thresholds.

The authors of the current study chose to use the cutoff of 10⬚ as the cutoff to identify asymmetries in TRROM based upon the results of previous studies in the literature. Ellenbecker et al5 found an 7-9⬚ side to side difference in TRROM in shoulders of elite junior tennis players. Reeser et al7 measured a difference of 11⬚ in 276 elite volleyball players.

Hurd et al6 and Ellenbecker et al4 also noted a 5⬚ difference in GH joint TROM in high school and professional baseball players, respectively. Measurement of the osseus changes on ultrasound that contribute to the total arc of motion changes found in the GH joints of overhead athletes, conducted by Wyland et al21 found a side to side difference of 9.4⬚ when adding glenoid retroversion and humeral retrotorsion. Reagan et al19 radiographically measured differences in humeral retrotorsion and found differences of 10.6⬚ when comparing the dominant to non-dominant shoulders. Clinically, it has been suggested that greater than a 5⬚ difference in TRROM be identified as pathologic in overhead athletes.34 Therefore, TRROM asymmetry of 10⬚ or greater was chosen as the threshold to encompass a previously defined meaningful difference in TRROM asymmetry14 and allow for a degree of measurement error commensurate to findings in the literature.43

Like TRROM, asymmetries identified within the FMS have been correlated with an increased risk of injury in the athletic population.28 The FMS shoulder mobility test examines the ability to use the upper quarters in a combination of opposing internal and external rotational patterns. An asymmetry in this test has been identified as a movement dysfunction that could contribute to injury or be the result of injury.31-33 Objective assessment of functional movement in the athletic population has been gaining attention recently in the literature because it has shown to have predictive value for identifying individuals at risk for athletic injury.23-30 The current study investigated the relationship between GH joint TRROM and a functional shoulder mobility test within a movement screen that has demonstrated validity in injury prediction in athletic populations.

The authors’ sought to investigate whether or not the FMS shoulder mobility test is an adequate screening test to identify clinically significant differences in TRROM, or p-GIRD.

The current findings showed that there was no statistically significant association between asymmetries in GH joint TRROM and the results of the shoulder mobility test (symmetry vs. asymmetry) of the FMS. In fact, out of 45 athletes that demonstrated an asymmetry in the FMS shoulder mobility test, only 17 also demonstrated an asymmetry of 10⬚ or greater in GH joint TRROM. 28 subjects did not demonstrate side-to-side differences in GH joint TRROM > 10⬚.

This data shows that the FMS shoulder mobility test is not sensitive enough to identify side-to-side asymmetries of this magnitude. TRROM and the FMS shoulder mobility tests are two very different assessments of the shoulder girdle. Rather than assessing total rotation of one glenohumeral joint, the FMS shoulder mobility test compares external rotation of one shoulder complex (including the glenohumeral joint, scapula-thoracic joint, and thoracic spine) plus internal rotation of the contralateral shoulder in combination with other factors that contribute to the ability to perform this reach test.

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The findings of the current study suggest that additional impairments other than GH TRROM differences may contribute to asymmetry in the FMS shoulder mobility test. The purpose of a movement screen is to examine movement patterns that test multiple contributors to normal function such as joint mobility, dynamic stability, and balance. The FMS shoulder mobility test considers these multiple contributors to normal movement and allows for a quick screen of the region to identify potential impairments that may lead to musculoskeletal injury. The inability to perform the movement without limitation or with symmetry suggests an underlying impairment during a basic functional movement pattern.

If the added demands of speed and repetition associated with athletic activity are applied, these impairments may contribute to the inability to properly move throughout the upper extremity kinetic chain in a complex pattern without compensatory means, exposing the region to injury risk. Musculoskeletal screening does not identify the specific impairments to the dysfunctional movement pattern, it only allows for an identification of a potential problem.

Further examination can allow for the identification of impairments contributing to a basic movement dysfunction. Contributors to dysfunction during the FMS shoulder mobility test may include thoracic extension mobility limitations, scapular mobility or stability limitations, and GH joint stability or mobility impairments. If the thoracic spine lacks the ability to extend, then the behind back reach internal rotation pattern can be limited. Lack of scapular mobility from tissue extensibility dysfunctions can also contribute to a lack of normal shoulder girdle movement that has been associated with injury.,7,9,38 Rotator cuff insufficiency has been shown to alter glenohumeral joint translation during active movements which can contribute to mobility deficits.39-42 Identifying causes of asymmetry found during movement screening may assist in the correction of functional movement and aid in injury prevention measures.

A limitation of this study can be found in the measurement error inherent with goniometry. Mullaney et al43 found that a 9⬚ change or greater is necessary to be sure a meaningful change in GH joint rotation occurs when accounting for goniometry measurement error. The authors attempted to address that concern by using a 10⬚ threshold of side-to-side

differences to determine the presence of an asymmetry. However, this concern may not have been totally addressed by using the 10⬚ threshold, as the level of agreement used to calculate this meaningful change threshold in the Mullaney study was for either internal or external rotation, not total rotation measures. The TRROM was calculated by adding the two separate measurements. The use of a level on the goniometer and a two-measurer methodology was chosen to limit measurement error inherently associated with goniometry. Though Wilk et al35 were able to demonstrate that the method used in the current study for goniometric measures of internal rotation had a higher reliability when compared to other methods, the reliability of this technique is still only fair (intraclass correlation reported at 0.62). Reliability of the TRROM measurement method was not a part of the current study, which may be a limitation.

CONCLUSION The FMS shoulder mobility test may provide information regarding scapular and thoracic mobility as well as contributors to glenohumeral mobility, however it is not related to passive TRROM measures of the glenohumeral joints in overhead athletes. Therefore, it is not likely to identify meaningful asymmetries in TRROM. Conversely, TRROM assessment does not consider any contributor to shoulder girdle movement other than glenohumeral joint ROM. Clinicians working with overhead athletes should consider using both assessments as a complete screening tool for injury prevention measures.

REFERENCES 1. Conte S, Requa RK, Garrick JG. Disability days in major league baseball. Am J Sports Med.2001; 29(4):431–436.

2. Fleisig GS, Barrentine SM, Escamilla RF, et al. Kinetics of baseball pitching with implications about injury mechanisms.. Am J Sports Med.1995;23(2):421-437.

3. McFarland EG, Wasik M. Epidemiology of collegiate baseball injuries. Clin J Sport Med.1998;8(1):10–13.

4. Ellenbecker TS, Roetert EP, Bailie DS, et al.

Glenohumeral joint total rotation range of motion in elite tennis players and baseball pitchers. Med Sci Sports Exerc.2002;34(12):2052-2056.

5. Ellenbecker TS, Roetert EP, Piorkowski PA, et al.

Glenohumeral joint internal and external rotation range of motion in elite junior tennis players.

J Orthop Sports Phys Ther. 1996;24(6):336-341.

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6. Hurd WJ, Kaplan KM, ElAttrache NS,et al. A profile of glenohumeral internal and external rotation motion in the uninjured high school baseball pitcher, part I: motion. J Athl Train. 2011;46(3):282-8.

7. Reeser JC, Joy EA, Poruczknik CA, et al.Risk factors for volleyball-related shoulder pain and dysfunction.

PM R. 2010;2(1):27-36.

8. Torres RR, Gomes JL. Measurement of glenohumeral internal rotation in asymptomatic tennis players and swimmers. Am J Sports Med. 2009;37(5):1017–1023.

9. Burkhart SS, Morgan CD, Kibler WB. The disabled throwing shoulder: spectrum of pathology. Part I: pathoanatomy and biomechanics. Arthroscopy. 2003;19(4):404–420.

10. Burkhart SS, Morgan CD, Kibler WB. The disabled throwing shoulder: spectrum of pathology. Part II: evaluation and treatment of SLAP lesions in throwers. Arthroscopy.2003;19(5):531–539.

11. Dines JS, Frank JB, Akerman M, et al. Glenohumeral internal rotation deficits in baseball players with ulnar collateral ligament insufficiency. Am J Sports Med. 2009;37(3):566–570.

12. Garrison JC, Cole MA, Conway JE,et al. Shoulder range of motion deficits in baseball players with an ulnar collateral ligament tear. Am J Sports Med.2012;40(11):2597-603.

13. Myers JP, Laudner KG, Pasquale MR,et al.

Glenohumeral range of motion deficits and posterior shoulder tightness in throwers with pathologic internal impingement. Am J Sports Med.2006;34(3):385-391.

14. Wilk KE, Macrina LC, Fleisig GS,et al. Correlation of glenohumeral internal rotation deficit and total rotational motion to shoulder injuries in professional baseball pitchers. Am J Sports Med. 2011;39(2):329– 335.

15. Crockett HG, Gross LB, Wilk KE, et al. Osseous adaptation and range of motion at the glenohumeral joint in professional baseball pitchers. Am J Sports Med.2002;30(1):20-26.

16. Edelson G. The development of humeral head retroversion. J Shoulder Elbow Surg. 2000;9(4):316318.

17. Meister K, Day T, Horodyski M,et al. Rotational motion changes in the glenohumeral joint of the adolescent/Little League baseball player. Am J Sports Med.2005;33(5):693-698.

rotation in the shoulder of college baseball players.

Am J Sports Med. 2002;30(3):354-360.

20. Sabick MB, Kim YK, Torry MR,et al. Implications for the development of proximal humeral epiphysiolysis and humeral retrotorsion. Am J Sports Med.2005;33(11):1716-1722.

21. Wyland DJ, Pill SG, Shanley E,et al. Bony adaptation of the proximal humerus and glenoid correlate within the throwing shoulder of professional baseball pitchers. Am J Sports Med.2012;40(8):185862.

22. Wilk KE, Meister K, Andrews JR. Current concepts in the rehabilitation of the overhead throwing athlete. Am J Sports Med.2002;30(1):136–151.

23. Butler RJ, Contreras M, Burton LC,et al.Modifiable risk factors predict injuries in firefighters during training academies. Work.2013;46(1):11-7.

24. Butler RJ, Lehr ME, Fink ML,et al. Dynamic balance performance and noncontact lower extremity injury in college football players: an initial study. Sports Health. 2013 Sep;5(5):417-22.

25. Cook G, Burton L, Hoogenboom B, Voight M. Functional movement screening: the use of fundamental movements as an assessment of function part 1. Int J Sports Phys Ther. 2014;9(3):396–409.

26. Cook G, Burton L, Hoogenboom B, Voight M. Functional movement screening: the use of fundamental movements as an assessment of function part 2. Int J Sports Phys Ther. 2014;9(4):549–563.

27. Kiesel K, Plisky PJ, Voight ML. Can serious injury in professional football be predicted by a preseason functional movement screen? N Am J Sports Phys Ther. 2007;2(3): 147–158.

28. Kiesel KB, Butler RJ, Plisky PJ Limited and Asymmetrical Fundamental Movement Patterns Predict Injury in American Football Players. J Sport Rehabil. 2014;23(2):88-94.

29. Lisman P, O’Connor FG, Deuster PA, et al.

Functional movement screen and aerobic fitness predict injuries in military training. Med Sci Sports Exerc. 2013;45(4):636-43.

30. Plisky PJ, Rauh MJ, Kaminski TW., et al. Star excursion balance test as a predictor of lower extremity injury in high school basketball players.

J Orthop Sports Phys Ther. 2006;36(12):911-919.

31. Kendall F.P., McCreary EK, Prvance PG, et al.

Muscles Testing and Function with Posture and Pain.

5th ed. Baltimore, MD: LippincottWilliams&Wilk; 2005.

18. Osbahr DC, Cannon DL, Speer KP. Retroversion of the humerus in the throwing shoulder of college baseball pitchers. Am J Sports Med.2002;30(3):347353.

32. Magee D. Orthopedic Physical Assessment. 5th ed. St. Louis, MI: Saunders Elsevier; 2008.

19. Reagan KM, Meister K, Horodyski MB,et al. Humeral retroversion and its relationship to glenohumeral

33. Cook, GE. Movement: Functional Movement Systems. Aptos, CA: On Target Publishing; 2010.

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34. Manske RC, Wilk KE, Davies GJ, Ellenbecker TE, Reinold M. Glenohumeral loss of motion: Friend or foe?. Int J Sports Phys Ther. 2013;8(5):537-551.

35. Wilk KE, Reinold MM, Macrina LC, et al.

Glenohumeral internal rotation measurements differ depending on stabilization techniques. Sports Health.

2009;1(2):131-136.

36. Morrissey D, Morrissey MC, Driver W, et al. Manual landmark identification and tracking during the medial rotation test of the shoulder: an accuracy study using three-dimensional ultrasound and motion analysis measures. Man Ther. 2008;13(6):529535.

37. Norkin C, White DJ. Measurement of Joint Motion: A Guide to Goniometry. 2nd ed. Philadelphia, PA: Davis; 1995.

38. Laudner KG, Moline MT, Meister K. The relationship between forward scapular posture and posterior shoulder tightness among baseball players. Am J Sports Med. 2010 Oct;38(10):2106-12.

39. Byram IR, Bushnell BD, Dugger K, et al. Preseason shoulder strength measurements in professional baseball pitchers: identifying players at risk for injury. Am J Sports Med. 2010;38(7):1375-82.

40. Hwang E, Carpenter JE, Hughes RE,et al. Shoulder labral pathomechanics with rotator cuff tears.

J Biomech. 2014;47(7):1733-8.

41. San Juan JG, Kosek P, Karduna AR. Humeral head translation after a suprascapular nerve block. J Appl Biomech. 2013;29(4):371-9.

42. Terrier A1, Reist A, Vogel A,et al. Effect of supraspinatus deficiency on humerus translation and glenohumeral contact force during abduction.

Clin Biomech (Bristol, Avon). 2007;22(6):645-51.

43. Mullaney MJ, McHugh MP, Johnson CP,et al.

Reliability of shoulder range of motion comparing a goniometer to a digital level. Physiother Theory Pract.

2010; 26(5):327-333.

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IJSPT

ORIGINAL RESEARCH

KINESIOLOGY TAPING AND THE WORLD WIDE WEB: A QUALITY AND CONTENT ANALYSIS OF INTERNETBASED INFORMATION Bryan G. Beutel, MD1 Dennis A. Cardone, DO1

ABSTRACT Background: Due to limited regulation of websites, the quality and content of online health-related information has been questioned as prior studies have shown that websites often misrepresent orthopaedic conditions and treatments. Kinesio tape has gained popularity among athletes and the general public despite limited evidence supporting its efficacy. The primary objective of this study was to assess the quality and content of Internet-based information on Kinesio taping.

Methods: An Internet search using the terms “Kinesio tape” and “kinesiology tape” was performed using the Google search engine. Websites returned within the first two pages of results, as well as hyperlinks embedded within these sites, were included in the study. These sites were subsequently classified by type.

The quality of the website was determined by the Health On the Net (HON) score, an objective metric based upon recommendations from the United Nations for the ethical representation of health information. A content analysis was performed by noting specific misleading versus balanced features in each website.

Results: A total of 31 unique websites were identified. The majority of the websites (71%) were commercial. Out of a total possible 16 points, the mean HON score among the websites was 8.9 points (SD 2.2 points). The number of misleading features was significantly higher than the balanced features (p < 0.001).

Fifty-eight percent of sites used anecdotal testimonials to promote the product. Only small percentages of websites discussed complications, alternatives, or provided accurate medical outcomes. Overall, commercial sites had a greater number of misleading features compared to non-commercial sites (p = 0.01).

Conclusions: Websites discussing Kinesio tape are predominantly of poor quality and present misleading, imbalanced information. It is of ever-increasing importance that healthcare providers work to ensure that reliable, balanced, and accurate information be available to Internet users.

Key Words: Internet information, kinesiology tape, quality Level of Evidence: IV

1

NYU Hospital for Joint Diseases Department of Orthopaedic Surgery New York, NY

CORRESPONDING AUTHOR Bryan G. Beutel, MD NYU Hospital for Joint Diseases Department of Orthopaedic Surgery New York, NY, 10010 Telephone Number: (212) 598-6000 Fax Number: (212) 598-7654 E-mail: bryanbeutel@gmail.com

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INTRODUCTION The advent of the Internet has profoundly altered the landscape of information exchange. As the Internet has expanded over the past few decades, so has its user population. Currently, nearly 2.5 billion people worldwide have Internet access, a dramatic increase of 566.4% since the year 2000.1 Large portions of the population within the United States (78.1%) and Canada (83%) have Internet access. Concomitant with this expansion has been an increasing influence on various facets of its usersâ&#x20AC;&#x2122; daily lives. From trends in popular culture to political issues, the Internet affords people rapid, convenient access to a vast array of information, much of which was previously restricted to libraries and similar institutions. This is particularly evident in the medical realm. Given the preponderance of accessible medical commentary on the Internet, over half of users search the Internet for health-related information at least once each month.2 In doing so, many patients make decisions about their healthcare, including medical and surgical treatments to pursue or even whether or not to seek out a physician, based upon online resources.

While the Internet serves as a powerful instrument for the dissemination of ideas, the quality of available information and resources is highly variable. Prior studies in the medical literature have demonstrated that websites frequently misrepresent orthopaedic conditions and treatments.3,4 Starman et al evaluated websites reviewing ten common sports medicine conditions and concluded that the quality and content of online orthopaedic health information is variable and generally poor.3 Similarly, Sambandam et al investigated the depiction of knee arthroscopy on the Internet and showed that websites are largely inadequate, outdated, and not accountable.4 These trends may stem from a dearth of many formal, enforced guidelines for regulating online content, coupled with the open forum nature of the Internet.5 In essence, accessibility may not necessarily equate to, or correlate with, quality. Consequently, patients may be making medical decisions based upon inaccurate media information.

One orthopaedic treatment modality, which has recently gained attention in the media is Kinesio taping. Originally designed in the 1970s, Kinesio tape (KMS LLC, Albuquerque, NM) was not commonly

used until the 2008 Olympics, during which time it was donated to numerous countries for use on their athletes. The brightly-colored tape was highly visible to onlookers, and as these high-profile athletes were seen adorning the product, media curiosity mounted.

Consequently, over the past several years, Kinesio tape has garnered increasing popularity among other athletes and the public in general. The product, a form of kinesiology tape, is reported to elevate the skin, thereby allowing improved blood flow and drainage of lymphatic fluid.6 This process is stated to facilitate pain relief and support injured muscles and joints for a more rapid recovery.7-10 Despite its popularity, there is limited evidence in the medical literature to support the efficacy of Kinesio taping. Various studies have indicated that Kinesio taping may improve cervical spine range of motion, quadriceps strength, and symptomatic shoulder impingement.11-14 Additionally, Kinesio taping may reduce pain and disability in patients with chronic, non-specific low back pain, but the effects may be too minimal to be clinically significant.15 More robust analyses have shown no benefit to the use of Kinesio taping. A systematic review of the existing literature by Mostafavifar et al. reported that there are few quality studies investigating this taping method, and, overall, there is insufficient evidence to support its use for treating musculoskeletal injuries.7 Other meta-analyses reached similar conclusions, stating that there is no clear evidence for the effectiveness of Kinesio taping for a variety of movement disorders or even as an alternative over other treatment modalities.16,17 Nonetheless, despite limited evidence supporting its use, Kinesio tape has been widely publicized and marketed through the Internet, with many taping courses heavily promoted to healthcare professionals. It remains unknown, however, what type and quality of information is available to patients online.

Therefore, the primary objective of this study was to characterize the Internet-based portrayal of Kinesio taping through the analysis of related websites. The authors hypothesized that the content and quality of online information would be incomplete, imbalanced, and largely poor.

METHODS In July 2013, the Google Chrome browser (version 27.0) was utilized to perform an Internet search for

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the terms “Kinesio tape” and “kinesiology tape.” In order to mimic real-world use, the search engine Google was chosen to execute the search, as data suggests that nearly 70% of Internet searches in the United States are powered by Google.18 Websites were included for analysis if they were contained within the first two pages of results returned by the search engine and discussed Kinesio taping. Because prior studies have demonstrated that users rarely look beyond the first two pages of search results when browsing for health-related information, this criterion further simulated actual patient use, and has been employed in other Internet search studies.4,19,20 Hyperlinks embedded within the resulting websites were also included for a more comprehensive investigation.

After identifying the websites, each was classified according to the type of site. These categories included commercial (e.g. received industry funding or sold Kinesio tape or related products), news-oriented (e.g. nonmedical sites with articles or stories), personal (e.g. public blogs or non-physician sites by therapists), physician (e.g. professional sites for physicians not affiliated with an academic institution), nonprofit (e.g. organizational sites receiving government funding or donations only), or academic (e.g. affiliated with a medical society, university, or journal). These classifications have been used in previous research.3 Websites were subsequently assessed for quality according to their compliance with the Health On the Net (HON) Foundation guidelines.21 Founded as a nonprofit organization accredited by the Economic and Social Council of the United Nations, HON has established criteria for ethical standards for maintaining transparency and purpose of website material (the HONcode) in order to protect Internet users from misleading health information. Using this code, Starman et al. devised an assessment (the HON score, scored from 0 to 16) to determine the compliance of a website to the HONcode’s core principles, with scores greater than or equal to 12 considered to be adequate (see Appendix).3 This objective quality measure includes factors such as the transparency of the website provider, provision of information regarding sources, accountability, and accessibility, among others. The HON scoring method was applied to all websites in this study.

Furthermore, a content analysis was performed.

Using a modified approach based upon methods employed in prior studies, each website was assessed for misleading and balanced features.20 Misleading features included inappropriate statements regarding Kinesio taping compared to those found in the scientific literature, medical imbalance (e.g. discussing only one perspective on this treatment), use of individual stories or testimonials, unsubstantiated promises, and the misuse of medical literature (e.g. exaggerating only positive results while inappropriately omitting negative ones). Balanced features were a discussion of alternative treatments, explanation of complications, use of accurate outcomes cited in the medical literature, and a discussion of appropriate candidates for Kinesio taping treatment. The presence or absence of each feature was recorded for every website.

Additionally, the date when the website was last updated or modified, as well as whether or not the site displayed the HONcode banner indicating that it met criteria set forth by HON, was documented.

Of note, sites are permitted to display the banner if they submit an application to the HON Foundation stating that they meet all of the core principles set forth by the organization, after which their site is extensively reviewed and subjected to periodic unannounced audits ensuring compliance with these ethical standards. The same single investigator reviewed all websites. Statistical analysis was performed using SPSS (version 19.0.1, IBM, Chicago, IL). Data were initially analyzed with the Kolmogorov-Smirnoff test to assess for normality of distribution. The t-test was used for the comparison of continuous variables when the data were normally distributed. The MannWhitney U test was used in lieu of the t-test when the data were not normally distributed. Significant differences were determined for comparisons, with twotailed p-values and a p < 0.05 indicating significance.

RESULTS The Internet search produced 44 websites meeting the inclusion criteria. After accounting for 13 duplicate sites, 31 were ultimately available for analysis.

Of these, 11 (35%) provided the date when the site was most recently updated or modified. The mean time interval between the last update and the date of the Internet search was 1.5 years (standard devia-

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tion (SD) 0.97 years, range 0.06 – 3.26 years). Additionally, only 1 website (3%) featured the HONcode banner. With regard to their classification, the websites were distributed among a variety of categories.

As noted in Table 1, the majority were commercial in nature, with 22 sites (71%) in this category. The remaining 9 websites were of variable type; the least common were physician and nonprofit sites.

Website quality analysis revealed predominantly low HON scores (Table 2). Out of a total possible of 16 points, the mean HON score among the websites was 8.9 points (SD 2.2 points) with actual scores ranging from 6 – 14 points. Review of the specific score criteria demonstrated areas in which the websites excelled and others where they were deficient.

This was manifested as high marks in criteria such as provider transparency (mean of 1.8 points out of Table 1. Distribution of website categories

Table 2. Health on the Net (HON) score analysis

a possible 2 points, SD 0.4 points), transparency of the site’s purpose and objective (each site achieved the maximum score of 1 point in this category), a clearly defined target audience (mean of 1.0 point out of a possible 1 point, SD 0.2 points), and accessibility of content (mean of 1.0 point out of a possible 1 point, SD 0.2 points). Conversely, low point values were evidenced in source information (mean of 0.5 points out of a possible 3 points, SD 1.0), with only 8 sites (26%) providing a statement of at least some of their sources. Sites were also largely deficient in clear and regular updating of their content (mean of 0.3 points out of a possible 1 point, SD 0.5 points) and providing an editorial policy on how content was selected for publication (mean of 0.2 points out of a possible 1 point, SD 0.4 points).

The content analysis assessed websites for misleading and balanced features. In terms of misleading content (Table 3), the majority of sites (71%) made inappropriate statements regarding the evidence or efficacy of Kinesio tape, while the same percentage displayed medical imbalance by only presenting information in favor of Kinesio taping. Testimonials and individual patient experiences were often used to promote the perceived effectiveness of the product. Unsubstantiated promises included “guarantees” for treatment and “pain free” outcomes.

Also, the medical literature was misused in several sites by inappropriately highlighting only positive results without any mention of negative data. Conversely, the frequency of balanced features found within each site was generally lower (Table 4). Discussions about alternatives to Kinesio tape for the treatment of muscle strains and arthralgias, such as anti-inflammatory medications and physical therapy, were found in a minority of websites. A review of the potential complications of Kinesio taping, including the development of rashes, blisters, pruTable 3. Analysis of misleading features of websites

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Table 4. Analysis of balanced features of websites

ritus, and edema, was only observed within a few sites.22 The majority of sites, however, did define the candidates for Kinesio taping. Overall, the number of misleading features was significantly higher than the balanced features (p < 0.001).

A comparison of the quality and content analyses by the type of website is shown in Table 5 and Figure 1.

The mean HON score for commercial websites was 8.5 points (SD 2.3 points), while the non-commercial sites (including news-oriented, personal, physician, and nonprofit) had a collective mean of 10.1 points (SD 1.7 points). The difference in mean HON scores approached, but did not attain, statistical significance (p = 0.06). Furthermore, commercial websites had a mean of 2.9 misleading features (out of a possible 5, SD 1.3), while non-commercial sites maintained a mean of 1.4 features (SD 1.5). No misleading features were identified in the physician or nonprofit websites. The difference in misleading features between the commercial and non-commercial sites was significant (p = 0.01). Additionally, no significant difference was observed between the number of balanced features (p = 0.94), with a mean of 1.1 balanced features (SD 0.7) and 1.1 features (SD 0.6) in the commercial and non-commercial sites, respectively.

Figure 1. Comparison of commercial and non-commercial site characteristics. Mean values with standard deviation bars are provided.

DISCUSSION The rapidly-expanding access to, and content of the Internet has established it as a prominent resource for gathering health-related information. Concomitant with this expansion has been a growing concern regarding the quality of the information presented to Internet users, as there is little regulation to monitor and enforce standards for website quality and the content contained therein. Prior studies have validated this concern with respect to health information, demonstrating a trend towards poor quality among websites.23,24 No prior analysis has been performed on Internetbased information regarding Kinesio taping. The rapid rise in popularity of Kinesio tape has occurred despite several studies, which have concluded that there is little evidence supporting its efficacy.7,16,17 The results of the current study demonstrate that websites discussing Kinesio taping are predominantly of poor quality. This is strongly indicated by the low mean HON score of 8.9 points, correlating to a 56% on a 100% scale, among all reviewed websites,

Table 5. Health on the Net (HON) and content analysis by category of website

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and is further revealed by the fact that only 1 out of 31 websites (3%) displayed the HONcode banner signifying compliance with HON quality guidelines.

These findings are even more concerning than those of Starman et al, who demonstrated that sites discussing common orthopaedic sports medicine diagnoses had a mean HON score of 9.3 points, with 24% of these websites displaying the HONcode banner.3 Moreover, while the sites in the present study were transparent with respect to purpose, objective, and provider, the majority provided no information regarding the sources (from the medical literature or elsewhere) used to reportedly substantiate their claims. Furthermore, most websites failed to provide a policy about how content is updated. As only 35% of sites displayed the date of the most recent content update, with some of those modifications occurring as long as 3 years ago, websites largely provided neither evidence that their content was up-to-date nor any intention to rectify this. Sambandam et al found similar poor rates (24%) of content updating in their review of knee arthroscopy websites.4 The lack of valid sources and regular updating of content raises concerns regarding the quality and legitimacy of the online information.

Additionally, the current study shows that websites frequently misrepresent Kinesio taping in favor of its advocates. This skewed portrayal is reflected in the statistically higher number of misleading features within each website compared to the balanced features (p < 0.001). Notably, medical imbalance and inappropriate statements regarding Kinesio taping were common, each documented in 71% of the websites. Moreover, sites frequently employed testimonials as a tool to promote Kinesio tape. These anecdotes, particularly when linked to athletes, celebrities, or those perceived by the public to have an expert opinion, can greatly influence peoplesâ&#x20AC;&#x2122; perceptions, as noted by Renaud et al.â&#x20AC;&#x2122;s work on mechanisms through which the media affects health behaviors.25 Many websites utilized these individual testimonials to justify unsubstantiated, global promises and guarantees of the purported effectiveness of Kinesio taping. Furthermore, few sites offered information regarding complications of, and alternatives to, this product, and nearly just as few stated accurate outcomes based upon published research. Con-

sidering these factors, much of the Internet-based information regarding Kinesio tape can be characterized as inaccurate and biased. As individuals are increasingly relying on the Internet for healthrelated advice, this inaccurate information could potentially delay appropriate treatment for these patients or preclude them from seeking professional medical attention. In certain circumstances, this could lead to serious consequences.

Similar to the results seen in previous research, the distribution of website types in our study demonstrates that commercial sites represent the single most common type of website (71%).3 Many of these websites sold Kinesio tape and related materials, the act of which can appear as a tacit endorsement of the product. Additionally, commercial sites had generally lower HON scores for quality and statistically higher numbers of misleading features compared to non-commercial sites. This, coupled with the abundance of commercial sites, further amplifies the misrepresentation of Kinesio tape. The prospect of financial gain from positive reviews (justified or not) of Kinesio tape may unduly influence the presentation of information on these sites. Also, the presence of only 1 physician site and the absence of any academic websites suggests that Internet users may have poor access to peer-reviewed literature and actual expert opinions utilized by the medical community to develop appropriate treatment algorithms.

This study is not without its limitations. Specifically, although the methods utilized were designed to replicate real-world Internet use based upon studies of general Internet search practices, it is possible that certain users may perform searches on different web browsers or delve more deeply into the returned results. Therefore, they may encounter different websites not assessed by this review, which may be of differing quality and content. This was mitigated in the current study, however, by the use of the popular Google search engine, which, as previously noted, is utilized in the vast majority of Internet searches, is the search tool of choice in prior studies, and is representative of actual patient use. Also, while the quality and content analyses were structured to be objective, an element of subjectivity may be present. Having all assessments performed by a single reviewer minimized variability; however, the

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use of one reviewer rather than two or more independent reviewers is also a limitation of the study since one reviewerâ&#x20AC;&#x2122;s interpretation may slightly bias the results. Furthermore, as the Internet evolves and search results change over time with the advent of new websites, it is possible that the results of this study may not necessarily reflect future searches.

Knowledge of the quality and accuracy of the Internet-based information available to patients will help clinicians appropriately educate patients on the benefits, shortcomings, and use of Kinesio taping. It may also assist clinicians in critically evaluating information brought in by patients. Consequently, healthcare providers should inform their patients about the apparent bias inherent to many websites dedicated to Kinesio taping, of which most patients may be unaware. In order to avoid misinformation, clinicians should also counsel patients on how to find accurate, objective, and balanced information. Based upon the findings in the current study, this would entail directing patients to non-commercial websites (e.g. university or other academic sites, hospital or physician websites) which discuss/cite relevant medical literature to support claims and provide alternatives to Kinesio tape. Commercial websites selling the product and using testimonials should be avoided as they are more likely to provide inaccurate and imbalanced information. Given this, it is increasingly important that healthcare providers work to ensure that reliable, balanced, and accurate information is available to Internet users. This information should be provided in terminology understandable to the general public, so that patients will be more inclined and comfortable seeking information and advice from these more balanced, trusted online resources.26,27 Additionally, advocating for establishing more enforceable guidelines to ensure appropriate quality and content of Internet-based health information should be a primary focus. Healthcare organizations and specialty associations can raise awareness of this by disseminating consensus statements on the importance of quality online health information, and collaborating with organizations such as the Health On the Net Foundation to promote such standards.

CONCLUSION The results of the current study reveal that websites discussing Kinesio tape are predominantly of

poor quality and present misleading and imbalanced information about the product. The majority of these sites are commercial in nature, which display a greater number of misleading features and tend to be of poorer quality compared to their non-commercial cohort. This distinction is noteworthy when educating patients on where to find accurate websites.

REFERENCES 1. Internet World Stats: Usage and Population Statistics.

February 17, 2013; http://www.internetworldstats. com/stats.htm. Accessed July 15, 2013.

2. Beredjiklian PK, Bozentka DJ, Steinberg DR, et al.

Evaluating the source and content of orthopaedic information on the Internet. The case of carpal tunnel syndrome. J Bone Joint Surg Am. 2000;82A:1540-1543.

3. Starman JS, Gettys FK, Capo JA, et al. Quality and content of Internet-based information for ten common orthopaedic sports medicine diagnoses. J Bone Joint Surg Am. 2010;92:1612-1618.

4. Sambandam SN, Ramasamy V, Priyanka P, et al.

Quality analysis of patient information about knee arthroscopy on the World Wide Web. Arthroscopy.

2007;23:509-513 e502.

5. Winker MA, Flanagin A, Chi-Lum B, et al. Guidelines for medical and health information sites on the internet: principles governing AMA web sites.

American Medical Association. JAMA. 2000;283:16001606.

6. Williams S, Whatman C, Hume PA, et al. Kinesio taping in treatment and prevention of sports injuries: a meta-analysis of the evidence for its effectiveness. Sports Med. 2012;42:153-164.

7. Mostafavifar M, Wertz J, Borchers J. A systematic review of the effectiveness of kinesio taping for musculoskeletal injury. Phys Sportsmed. 2012;40:3340.

8. Bicici S, Karatas N, Baltaci G. Effect of athletic taping and kinesiotaping(R) on measurements of functional performance in basketball players with chronic inversion ankle sprains. Int J Sports Phys Ther.

2012;7:154-166.

9. Krajczy M, Bogacz K, Luniewski J, et al. The inďŹ&#x201A;uence of Kinesio Taping on the effects of physiotherapy in patients after laparoscopic cholecystectomy. ScientiďŹ cWorldJournal.

2012;2012:948282.

10. Karatas N, Bicici S, Baltaci G, et al. The effect of Kinesiotape application on functional performance in surgeons who have musculo-skeletal pain after performing surgery. Turk Neurosurg. 2012;22:83-89.

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11. Kaya E, Zinnuroglu M, Tugcu I. Kinesio taping compared to physical therapy modalities for the treatment of shoulder impingement syndrome. Clin Rheumatol. 2011;30:201-207.

12. Thelen MD, Dauber JA, Stoneman PD. The clinical efficacy of kinesio tape for shoulder pain: a randomized, double-blinded, clinical trial. J Orthop Sports Phys Ther. 2008;38:389-395.

13. Gonzalez-Iglesias J, Fernandez-de-Las-Penas C, Cleland JA, et al. Short-term effects of cervical kinesio taping on pain and cervical range of motion in patients with acute whiplash injury: a randomized clinical trial. J Orthop Sports Phys Ther. 2009;39:515-521.

14. Wong OM, Cheung RT, Li RC. Isokinetic knee function in healthy subjects with and without Kinesio taping. Phys Ther Sport. 2012;13:255-258.

15. Castro-Sanchez AM, Lara-Palomo IC, MataranPenarrocha GA, et al. Kinesio Taping reduces disability and pain slightly in chronic non-specific low back pain: a randomised trial. J Physiother.

2012;58:89-95.

16. Kalron A, Bar-Sela S. A systematic review of the effectiveness of Kinesio taping - Fact or fashion? Eur J Phys Rehabil Med. 2013;49:699-709.

17. Morris D, Jones D, Ryan H, et al. The clinical effects of Kinesio Tex taping: A systematic review.

Physiother Theory Pract. 2013;29:259-270.

18. comScore Releases May 2013 U.S. Search Engine Rankings. June 12, 2013; http://www.comscore. com/Insights/Press_Releases/2013/6/comScore_ Releases_May_2013_U.S._Search_Engine_Rankings.

Accessed July 17, 2013.

19. Eysenbach G, Kohler C. How do consumers search for and appraise health information on the world

20.

21.

22.

23.

24.

25.

26.

27.

wide web? Qualitative study using focus groups, usability tests, and in-depth interviews. BMJ. 2002;324:573-577.

Deren ME, DiGiovanni CW, Feller E. Web-based portrayal of platelet-rich plasma injections for orthopedic therapy. Clin J Sport Med. 2011;21:428-432.

Health On the Net Foundation. June 13, 2013; http://www.hon.ch/HONcode/Pro/Visitor/visitor. html. Accessed July 10, 2013.

Chou YH, Li SH, Liao SF, et al. Case report: Manual lymphatic drainage and Kinesio taping in the secondary malignant breast cancer-related lymphedema in an arm with arteriovenous (A-V) fistula for hemodialysis. Am J Hosp Palliat Care.

2013;30:503-506.

Greene DL, Appel AJ, Reinert SE, et al. Lumbar disc herniation: evaluation of information on the internet. Spine (Phila Pa 1976). 2005;30:826-829.

Moshirfar A, Campbell JT, Khasraghi FA, et al.

Evaluating the quality of Internet-derived information on plantar fasciitis. Clin Orthop Relat Res. 2004;421:60-63.

Renaud L, Bouchard C, Caron-Bouchard M, et al. A model of mechanisms underlying the influence of media on health behaviour norms. Can J Public Health. 2006;97:149-152.

Hansberry DR, Agarwal N, Shah R, et al. Analysis of the readability of patient education materials from surgical subspecialties. Laryngoscope. 2014;124:405412.

Fabricant PD, Dy CJ, Patel RM, et al. Internet search term affects the quality and accuracy of online information about developmental hip dysplasia. J Pediatr Orthop. 2013;33:361-365.

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Appendix. Health on the Net (HON) sample scoring sheet

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IJSPT

ORIGINAL RESEARCH

OHIO PHYSICAL THERAPISTSâ&#x20AC;&#x2122; ACCURACY IN IDENTIFYING ABNORMALITIES ON DIAGNOSTIC IMAGES WITH AND WITHOUT A CLINICAL VIGNETTE Abby Morris, DPT1 Chad Cook, PT, PhD, MBA, FAAOMPT2 Amy Hassen, PT, DPT, OCS, MTC1

ABSTRACT Background: A strong understanding of diagnostic imaging has been advocated for physical therapists. There have been recent changes in physical therapy curricula and increased opportunities to utilize imaging during clinical practice Purpose: The aim of this study was to explore the ability of practicing clinicians to accurately identify selected musculoskeletal conditions on plain-film radiograph (X-ray), magnetic resonance imaging (MRI), and computed tomography scan (CT scan). Further, to determine whether improvements in identification of pathology occur when the clinical scenario is added to the imaging and whether there are related training/exposure factors.

Methods: A cross- sectional electronic survey was sent out to physical therapists in the state of Ohio. Participants were asked to identify conditions (cervical fracture, anterior cruciate ligament tear, and avascular necrosis of the femoral head) first given diagnostic images only, and then given the images and a clinical scenario.

Results: Eight hundred sixty-six surveys of the 7537 sent out were eligible for analysis. With clinical scenarios, 61.3% of respondents were correct with the ACL injury identified on MRI, 36.4% for identification of the cervical spine fracture on CT and 25.6% for identification of avascular necrosis on plain film. The accuracy significantly improved (p<0.01) with the addition of the clinical information for all three of the diagnoses. The most remarkable improvement was seen with the AVN diagnosis on plain film radiograph (365.5% improvement), followed by the ACL injury on MRI (27.2% improvement) and cervical fracture diagnosis on CT scan (17.8% improvement). Finally, formal and informal training, board certification through the APTA and to a lesser extent, degree level, all improved diagnostic accuracy.

Conclusions: A clinical scenario paired with images notably improved identification of pathology. Physical therapists were better at identifying the ACL pathology that was presented on MRI. This is a common diagnosis to physical therapists and was paired with a relatively common imaging modality. This study suggests that physical therapists can improve accuracy with identifying pathologies on diagnostic images through a physical therapy curriculum or post-graduation through certifications and continuing education.

Level of Evidence: Level 4 Keywords: certifications, degree, diagnostic imaging, education, survey

1 2

Walsh University, North Canton, OH U.S.A. Duke University, Durham, NC, USA

This study was approved by the Walsh University Human Subject Review Committee (13-43).

Acknowledgements We would to thank the following for the contribution of the diagnostic images:Â Rob Liottta, Steven Goldstein, Hani Alsalam, and Radiopaedia

CORRESPONDING AUTHOR Dr. Amy Hassen Department of Physical Therapy Walsh University 2020 East Maple Street North Canton, OH 44720 E-mail: ahassen@walsh.edu

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INTRODUCTION The American Physical Therapy Association’s (APTA) Vision 2020 statement was created as a foundation for physical therapists’ autonomous practice.1 Professional progression toward autonomous practice requires knowledge advancement and competencies in areas such as diagnostic imaging, pharmacology, and surgical applicability; since patients commonly consult with their physical therapist on care-related matters beyond the therapist’s traditional scope of practice. Advancements in these areas, specifically imaging, have occurred through formal curricular training, through extra-curricular and extra-clinical training, and direct exposure/responsibilities in clinical practice.

As early as 1999, Threlkeld et al2 underscored the importance of diagnostic imaging in Doctorate of Physical Therapy (DPT) curriculums in order to aid in the patient evaluation, diagnosis, and management.2 As of 2007, most DPT curricula had adopted formal imaging training within required coursework.3 Training may be embedded in practice-based courses or may consist of a dedicated class that is focused on identification of structures and pathologies on multiple imaging modalities to aid in clinical decision making. The importance of training related to diagnostic imaging has been quantified via survey, in which 97% of the academic and clinical physical therapist respondents felt that diagnostic imaging should be included in entry-level doctorate of physical therapy curricula.3 Practicing physical therapists also feel that extra-curricular and extra-clinical knowledge and understanding of imaging could potentially improve patient care skills.4 Despite this, there is an understanding that most physical therapists rely solely on an external interpretation of an image (e.g., a radiologist’s interpretation), rather than viewing the image to gain further understanding of their patient’s presentation.5 While the authors agree that the responsibility of interpreting the image belongs to the radiologist, viewing the image and being able to recognize relevant pathology can aid in management of patients’ conditions.

Deyle6 emphasized that physical therapists (regardless of imaging privileges) need to be aware of imaging indications, risks and benefits and should consider requesting an imaging study with appropriate rationale. Imaging knowledge could improve a clinician’s

ability to refer for imaging when results are poor, when imaging may influence management decisions and when a positive finding for imaging may prompt the need for proper surgical intervention.6 Direct exposure and responsibilities have also elevated imaging knowledge among physical therapists. Many physical therapists are employed in direct access environments and have capabilities to order diagnostic images.7-11 Military-based physical therapists serve as physician extenders, practice direct access, and have the ability to order diagnostic images and certain medications as well as restrict work and activity.8 Civilian physical therapists in the United States as well as other countries are also practicing in this manner. 9,1115 Evidence exists that when physical therapists refer patients for imaging they aid in preventing overutilization of imaging techniques, as physical therapists tend to be appropriately conservative. 8,12 In addition to ordering images in appropriate circumstances,10,11,16 physical therapists have better clinical diagnostic accuracy than all providers except orthopaedic surgeons (with whom they were shown not to be different). 16 Additionally, when patients are managed by physical therapists working as physician extenders versus management by orthopedic surgeons, there is no clinically or statistically difference in outcomes, except an improvement in patient satisfaction for those being managed by physical therapists.12 McKinnis5 emphasizes benefits that exist when physical therapists view the images themselves: 1) viewing provides a more comprehensive evaluation and 2) it provides a unique perspective from a profession (physical therapy) that often assesses information on an image differently than a referring physician or radiologist. Past studies have shown that when clinical information is added to the assessment of an image for medical physicians, diagnoses are more accurate.17 To the authors’ knowledge, there are no studies that have evaluated whether identification of pathology on imaging improves with the addition of clinical information.

For physical therapists, a strong understanding of all aspects of diagnostic imaging has previously been advocated.18 Since recent changes in physical therapy formal curricula and opportunities to utilize imaging during clinical practice have notably increased, the authors were interested in the ability

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of practicing clinicians to accurately identify selected musculoskeletal conditions on plain-film radiograph (X-ray), magnetic resonance imaging (MRI), and computed tomography scan (CT scan). Secondarily, the authors were interested in examining whether improvements in identification of pathology occur when the clinical scenario is added to the imaging and whether there are training/exposure-related factors associated with the accuracy of the diagnosis.

In particular, training/exposure-related factors of: a) imaging training, b) different levels of educational training, and c) value of certification of specialization within the APTA were of interest. Findings may help assess appropriateness of physical therapistsâ&#x20AC;&#x2122; capacity to view diagnostic images in clinical practice and may identify areas of training/exposure that are superior to others. To the authorsâ&#x20AC;&#x2122; knowledge there are no studies that have evaluated the ability of licensed physical therapists to identify pathology on selected images. Nor have studies investigated the value of the clinical scenario or training/exposure factors and how they related to physical therapistâ&#x20AC;&#x2122;s ability to identify pathology on images. Therefore, the purpose of this study was to explore the ability of practicing clinicians to accurately identify selected musculoskeletal conditions on plain-film radiograph (X-ray), magnetic resonance imaging (MRI), and computed tomography scan (CT scan) and to determine whether improvements in identification of pathology occur when the clinical scenario is added to the imaging, and whether there are related training/exposure factors.

METHODS Design The study involved a cross sectional, electronic survey completed in November of 2013. In order to complete the survey, respondents were required to provide electronic informed consent. The study was approved by the Walsh University Human Subject Review Committee (13-43).

Survey Development An 18-question survey was developed by two of the authors (AM and AH). The survey has three primary sections, with the first section asking the respondent to rate how confident he was in his ability to interpret diagnostic imaging results on either plain

film radiograph, MRI or CT scan. The next section involved multiple images (plain film radiograph, an MRI, and a CT scan) that were representative of three actual diagnoses (cervical fracture, anterior cruciate ligament tear, and avascular necrosis of the femoral head). (The actual images can be found in the appendix.) First, the participant was given the image only and asked to type a diagnosis in the space provided. Permission for the images was received by Radiopaedia.org and MedPix (rad.usuhs.edu). Order of viewing was not randomized and included 1) anterior cruciate ligament injury then 2) cervical fracture and then 3) avascular necrosis of the femoral head. Each of the three clinical scenarios and survey questions are represented in Appendix I. The second part to each question included the same images but also included a clinical scenario associated with those images. The clinical scenario provided the respondent with the mechanism of injury (tennis match, MVA, insidious onset). The clinical scenarios are included in Appendix 1. Once again the respondent was asked to type a diagnosis in the available space. The last section of the survey was designed to outline the exposure, training and work environment of the respondent.

Case Content Validity The lead author wrote the cases and found published images to use. Information on mechanisms of injury, signs and symptoms, risk factors, and differential diagnosis were extracted from the literature and used to formulate the cases. The cases were then passed on to the other authors who are content experts in orthopedic physical therapy.

These authors reviewed the cases to ensure appropriate content and clarity. One content expert has 24 years of clinical experience specializing in orthopedics and orthopedic research with over 170 peer reviewed publications in that area. The other content expert has been treating patients with orthopaedic dysfunction for 15 years, has achieved a manual therapy and orthopaedic clinical specialization and has been teaching orthopaedic content for 5 years.

Respondents Convenience sampling was used to recruit respondents. Because of the availability of a database, which included all practicing physical therapists, Ohio-based

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physical therapists were targeted. In order to be eligible for the study, the physical therapist had to have an active license to practice physical therapy as well as a valid email address on file with the Ohio Occupational Therapy, Physical Therapy, and Athletic Trainers Board. Respondents were recruited via email.

Procedure The survey was distributed through SurveyMonkey, Inc. (US). The survey was open for 5½ weeks; four reminder emails with the survey link were sent during that period requesting participation. Survey responses were confidential and could not be traced back to the participant. To further reduce the risk of bias during the coding process each variable in question was coded in an isolated fashion.

Data Analysis Descriptive statistics, diagnostic accuracy of imaging detection, with and without clinical scenarios, and associations related to exposure, training and confidence levels of the respondents were calculated using SPSS 22.0. Descriptive statistics were first derived using frequencies, to produce the population frequencies. Chi-Square analyses were used to determine the difference in correctness in interpretation for each set of images with and without the clinical vignette. Accuracy of the participants’ written responses was determined by the lead author. The radiologists’ published interpretation of the images utilized in this study was used as the standard for comparison. Regression analyses, using binary logistic regressions were used to predict exposure, training and confidence levels of the respondents. In all three regression analyses, dependent variables included the accuracy of the plain-film radiograph, the MRI, and the CT scan, all with the clinical scenarios included. In all three categories the reference category was an “inaccurate” diagnosis. For all regression analyses, beta values with standard deviations, odds ratios and 95% confidence intervals, and p values were reported. A p value of <0.05 was used for all analyses for determining statistically significant differences.

RESULTS A total of 7537 surveys were sent out to practicing Ohio physical therapists. One thousand one hundred

forty (1140) surveys were returned for a response rate of 15.1%. One hundred and eleven (111) subjects opted out of the survey, and 47 emails were reported as “undeliverable”. Of the 1140 surveys completed, 274 did not complete the imaging questions. Subsequently, 866 responses were included in data analysis for a final response rate of 11.5%. There were no missing values in the final 866 respondents included in the data analyses.

Descriptive characteristics of the participants are shown in Table 1. Half the respondents are doctorally trained. The majority work in an outpatient setting and are employed full time. Twelve percent (12%) of the respondents earned an APTA certification or a different certification that was not sanctioned by the APTA. The most commonly acquired imaging training was received as a requirement for an entry level physical therapy degree.

Table 2 demonstrates the accuracy levels of the participants in identifying the correct pathology on MRI, plain films, and CT scan with and without the clinical scenario. The highest level of accuracy was noted with the ACL injury noted on MRI followed by the cervical spine fracture on CT and finally avascular necrosis on plain film. In all three cases, the accuracy significantly improved (p<0.01) with the addition of the clinical information. The most remarkable improvement was seen with the AVN diagnosis on plain film radiograph where accuracy improved by 365.5% when provided with the clinical scenario. Accuracy improved by 27.2% for the ACL injury on MRI and by 17.8% for the cervical fracture diagnosis on the CT scan.

Although participants demonstrated the greatest number of correct responses with the MRI (ACL) question, there was a wide array of incorrect answers.

When presented with the image only, over 25% of participants responded with a diagnosis of a variety of different fractures. Other incorrect diagnoses included meniscus tears, posterior cruciate ligament injury, arthritis and degenerative joint disease.

When presented with the image only for the CT-scan (cervical fracture) question participants responded the most, with either spondylosis or spondylolisthesis (20.7%), upper cervical fractures (17.1%), and degenerative disc disease (11.7%). When presented

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Table 1. Descriptive Statistics.

V ar i a b l e Highest Degree Earned

Frequency (percentage) DPT/PhD = 50.0% MPT/BSPT= 50.0%

Entry Level Physical Therapy Degree

DPT= 33.6% MPT/BSPT= 66.4%

P ra ct ic e S e tt i n g

Outpatient (Hospital- Based, Private Outpatient, Health and Wellness Facility) = 53.1% Inpatient (Acute care, Subacute, SNF/ECF/ICF) = 27.5% Other (Home Care, School System, Academic Institution, Research Center, Industry, All Other) =19.4%

Specialization

OCS and SCS = 8.3% Non OCS and SCS = 18.1% APTA Certifications = 12.0% Non APTA Certifications = 14.7%

Employment Status

Full-time = 73.2% Part-time = 17.3% PRN=5.1% Retired or Unemployed= 4.3%

Imaging Training

Requirement for Entry Level Physical Therapy degree = 45.3% Requirement for Post Professional degree = 11.1% CEU Course = 6.1% O t h er = 2 3 . 1 %

Table 2. Accuracy of Imaging and Imaging plus Clinical Scenarios.

Item

With Imaging Only

With Imaging and Clinical Scenario Anterior Cruciate 417 (48.2%) = correct 531 (61.3%) = correct Ligament Rupture (MRI) 449 (51.8%) = incorrect 335 (38.7%) = incorrect Avascular Necrosis of the 48 (5.5%) = correct 222 (25.6%) = correct Hip (Radiograph) 818 (94.5%) =incorrect 644 (74.45.8%) = incorrect Cervical Spine Fracture 268 (30.9%) = correct 315 (36.4%) = correct (CT) 598 (69.1%) = incorrect 551 (63.6%)= incorrect MRI= Magnetic resonance image; CT= Computerized tomography

with the clinical scenario in addition to the image respondents continued to respond with spondylosis or spondylolisthesis and upper cervical fractures as the leading responses, but less respondents diagnosed the patient with degenerative disc disease.

Forms of cervical nerve root impingement, specifically between C4-C6, were also incorrect answers provided when with the image and clinical scenario were given.

The plain film radiograph (hip AVN) had similar incorrect responses for both the image only and image and

P value <0.01 <0.01

<0.01

clinical scenario questions. Over half of all incorrect answers were some form of arthritis. Other prevalent incorrect responses were degenerative joint disease and various fractures.

All forms of training improved diagnostic accuracy for diagnosis of the ACL, Hip AVN, and cervical fracture images and clinical scenarios. The most robust improvements depended on the imaging scenario as imaging training during continuing education courses (CEU) was the strongest predictor for accuracy for the MRI (ACL), other formal or informal

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imaging training was strongest for accuracy of the CT-Scan (Cervical Fracture) and imaging training during entry level program was the strongest for the plain-film radiograph (hip AVN) (Table 3).

Highest degree earned and primary degree received associated with accuracy are seen in Table 4. Possessing a DPT as a primary degree versus an undergraduate degree was a strong predictor for accuracy for the MRI (ACL), but was not significant for the plain-film radiograph (hip AVN) or CT- Scan (cervical fracture). Having a primary masters degrees versus an undergraduate degree did not improve accuracy. Again, possession of a DPT as the highest degree earned was a predictor for accuracy for the MRI (ACL), but not for the other forms of imaging.

Table 5 provides information on the utility of APTA and non-APTA sanctioned certifications. Orthopedic (OCS) and sports (SCS) board certifications within the APTA, along with â&#x20AC;&#x153;otherâ&#x20AC;? APTA certifications (including OCS and SCS) was associated with

increased accuracy for the MRI (ACL) scenario, CTscan (cervical fracture) and the plain-film radiograph scenario (hip AVN) where non APTA certifications was associated with increased accuracy for only the MRI (ACL) scenario. The highest odds ratios involve those with OCS and SCS certifications.

Table 6 provides information on practice setting. Working in an outpatient setting significantly increased accuracy only for the MRI (ACL scenario). Treating a population that is at least 75% orthopaedic was significant for increased accuracy for the MRI (ACL) and CT-scan (cervical fracture) scenarios.

DISCUSSION The purpose of the current study was three fold: First, to determine the overall ability of licensed physical therapists to identify pathology using three different imaging modalities with conditions of the hip, cervical spine and knee. Second, to investigate whether providing a concurrent clinical scenario improved the accuracy of the identification. Third, to evaluate

Table 3. Imaging Training Associated with Accuracy of Imaging plus Clinical Scenario Assessment.

Variable

Odds Ratio (95% CI)

p- value

Correctness of ACL Diagnosis Imaging training during entry level program Imaging training post-graduate degree

3.26 (2.30, 4.62)

<0.01

2.72 (1.63, 4.52)

<0.01

Imaging training during CEU courses

3.72 (1.82, 7.60)

<0.01

Other formal or informal imaging training

2.99 (2.00, 4.48)

<0.01

Correctness of AVN Diagnosis Imaging training during entry level program Imaging training post-graduate degree

3.46 (2.22, 5.39)

<0.01

2.73 (1.56, 4.79)

<0.01

Imaging training during CEU courses 3.22 (1.71, 6.05) Other formal or informal imaging 4.24 (2.60, 6.92) training Correctness of Cervical Fracture Diagnosis

<0.01 <0.01

Imaging training during entry level program Imaging training post-graduate degree

5.28 (3.46, 8.05)

<0.01

5.27 (3.07, 9.04)

<0.01

Imaging training during CEU courses

4.82 (2.50, 9.29)

<0.01

Other formal or informal imaging training

3.76 (2.35, 6.01)

<0.01

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Table 4. Primary Degree and Highest Degree Obtained Associated with Accuracy of Imaging plus Clinical Scenario Assessment.

Variable

Odds Ratio (95% CI)

p value

Correctness of ACL Diagnosis Primary Physical Therapy Degree DPT*

0.51 (0.35, 0.75)

Primary Physical Therapy Degree Masters Degree* Highest Degree Earned

0.78 (0.53, 1.16) 1.66 (1.20, 2.30)

<0.01 0.23 <0.01

Correctness of AVN Diagnosis Primary Physical Therapy Degree DPT*

0.95 (0.65, 1.4)

0.80

Primary Physical Therapy Degree Masters Degree* Highest Degree Earned

0.89 (0.60, 1.3)

0.57

1.12 (0.81, 1.56)

0.50

Correctness of Cervical Fracture Diagnosis Primary Physical Therapy Degree DPT*

0.88 (0.62, 1.25)

0.47

Primary Physical Therapy Degree Masters Degree * Highest Degree Earned

0.91 (0.62, 1.33)

0.62

1.11 (0.82, 1.51)

0.49

* BS degree was the reference variable

factors associated with accuracy when both the imaging and clinical scenario were provided. In particular, the associative value of a) imaging training, b) different levels of educational training, and c) value of certification of specialization within the APTA were analyzed. The current findings suggest that although diagnosis using imaging notably improves with a clinical scenario, it appears that the diagnosis may be dependent on both the clinical condition and the imaging modality. Further, the current findings suggest that formal and informal training, board certification through the APTA and to a lesser extent, degree level, can also influence diagnostic accuracy.

There are likely several reasons for these findings.

Correct diagnoses (identification of pathology) on each of the three imaging scenarios with clinical information ranged from a low of 25.6% (hip AVN, plain film radiograph) to a high of 61.3% (ACL tear, MRI). Whether these values are similar to other health providers with image viewing privileges is unknown. The lower accuracy scores for the hip and cervical conditions may be reflective of the challenging natures of both conditions. It is well known that a diagnosis of AVN is an exceptionally difficult diagnosis to make in the early stages of the condition,19

and that staged MRIâ&#x20AC;&#x2122;s may be most useful during the diagnosis20 followed by CT Scan.21 In a radiology study avascular necrosis was misdiagnosed 42.27% of the time by radiologists on plain film radiograph; the author found that relevant clinical history helped to reduce the rate of misdiagnosis, which supports the current findings.22 The imaging modality used in this study was plain film radiograph which exhibits low to moderate sensitivity values in detection of hip AVN.23 Cervical spine fractures are often overlooked on plain film radiographs by radiologists and with clinical examination by primary care physicians.24 Absence of initial neurological defects25 or less common mechanism of injury (low velocity versus high velocity MVA) further complicates cervical spine fracture detection.26 Plain film sensitivity of cervical spine fracture is 52% compared with 98% for CT scan.27 Although CT scan is an excellent study for detection of cervical spine fracture,28 the fracture was shown to be difficult for physical therapists to identify in this study. This may due to the challenging nature of reading CT scans, a decreased familiarity with CT scans or the fact that only three images were provided in this study.

Prevalence may also have played a role in picking the diagnosis from the image. For example, a lateral

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Table 5. Certifications or Specializations associated with Accuracy of Imaging plus Clinical Scenarios (Univariate Analyses).

Variable

Odds Ratio (95% CI)

p value

Correctness of ACL Diagnosis OCS and SCS*

4.88(2.39, 9.94)

<0.01

Non OCS and SCS†

1 . 39 ( 0. 96, 2. 00 )

0. 0 8

APTA Certifications‡

2 .4 4 ( 1. 50, 3. 97 )

<0.01

Non APTA Certifications§

1.57 (1.05, 2.37)

0.03

Correctness of AVN Diagnosis OCS and SCS*

1.87 (1.13, 3.11)

Non OCS and SCS†

1 . 38 ( 0. 94, 2. 02 )

0.02 0. 1 0

APTA Certifications‡

1 .8 8 ( 1. 22, 2. 91 )

<0.01

Non APTA Certifications§

1.23 (0.80, 1.88)

0.35

Correctness of Cervical Fracture Diagnosis OCS and SCS*

2.36 (1.45, 3.84)

<0.01

Non OCS and SCS†

1 . 22 ( 0. 85, 1. 17 )

0. 2 8

APTA Certifications‡

1 .7 4 ( 1. 15, 2. 62 )

<0.01

Non APTA Certifications§

1.30 (0.89, 1.91)

0.18

* OCS and SCS = Orthopedic Certified Specialist and Sports Certified Specialist † Non OCS and SCS = Other American Board of Physical Therapy Specialties (Cardiac,

Electrotherapy, Geriatric, Pediatric, Neurologic, Women’s Health), Fellow of the American Academy of Orthopedic Manual Physical Therapy, Mechanical Diagnosis and Therapy, Certification in Orthopedic Therapy, Constraint Induced Movement Therapy, Manual Therapy Certification, ‡ APTA Certifications = Other American Board of Physical Therapy Specialties (Cardiac, Electrotherapy, Geriatric, Orthopedic, Pediatric, Neurologic, Sports, Women’s Health) * NON APTA Certifications = Fellow of the American Academy of Orthopedic Manual Physical Therapy, Mechanical Diagnosis and Therapy, Certification in Orthopedic Therapy, Constraint Induced Movement Therapy, Manual Therapy Certification,

Table 6. Practice Setting Associated with Accuracy of Imaging plus Clinical Scenarios (Univariate Analyses).

Variable

Odds Ratio (95% CI) Correctness of ACL Diagnosis Outpatient Setting versus other 1.57 (1.13, 2.17) Population is 75% orthopedic or higher 1.86 (1.31, 2.62) Correctness of AVN Diagnosis Outpatient Setting versus other 0.98 (0.71, 1.36) Population is 75% orthopedic or higher 1.08 (0.77, 1.52) Correctness of Cervical Fracture Diagnosis Outpatient Setting versus other 1.16 (0.86, 1.57) Population is 75% orthopedic or higher 1.37 (1.01, 1.87)

view of an MRI of the knee may have prompted the selection of an ACL injury since this is the most commonly performed imaging modality and position used for ACL tear detection.29 Recently physical therapists have had a number of opportunities to

p value <0.01 <0.01 0.91 0.63 0.33 0.04

view MRIs in clinical practice thus increasing exposure to this diagnostic modality.8,16,30-32 Imaging-only accuracy ranged from 5.5% correct responses (using a radiograph and the diagnosis of

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hip AVN) to 48.2% correct responses (diagnosis of ACL tear using an MRI). In all three scenarios, accuracy improved with the addition of a clinical scenario.

Changes in identification ranged from a low of 17.8% improvement for the cervical spine fracture on a CT scan to a high of 365.5% improvement for identifying hip AVN with a radiograph. This finding is consistent with the medical literature on providers reading and interpreting radiographs and CT scans. Loy and Irwig17 reported that clinical information improved imaging reading accuracy, in conditions such as digitized chest, wrist, and general bone assessment.

Their review17 found no instances in which clinical information provided deleterious results.

The authors were able to identify a number of training/exposure opportunities that were associated with improved accuracy in imaging detection when the clinical scenario was provided including: training through an entry-level program, training through a post-graduate degree, training during a CEU course, and through other informal imaging training. No known studies that have assessed the accuracy of physical therapists for use of imaging. Higher educational training (having a doctorate of physical therapy rather than a master’s or bachelor’s degree in physical therapy) only seemed to influence the accuracy of the ACL diagnosis. To the authors’ knowledge, studies have not investigated the impact the DPT has on clinical decision making compared to other entrylevel degrees.

In addition, board certification from the APTA was associated with increased accuracy. This reveals that orthopaedic and sports clinical certification increases accuracy with diagnosing based on imaging and clinical scenarios compared to all other certifications both APTA and non-APTA. Board certification is a formal recognition for physical therapists with advanced clinical knowledge, experience, and skills in a special area of practice. To be eligible for board certification, clinicians must submit evidence of 2000 hours of direct patient care and/or exhibit evidence of residency or fellowship training.33 These factors may also expose clinicians to additional images in practice. Childs’ et al34 also found that when evaluating the results of a standardized exam that had been previously been validated in the literature,35 physical therapists who were board certified in orthopedic or

sports physical therapy achieved significantly higher scores and passing rates than their non- board certified colleagues. Jette36 discovered that physical therapists with an OCS were almost twice as likely to make a correct determination on management for patients with critical medical and musculoskeletal conditions.

This is consistent with our findings that those holding the specific APTA certifications OCS and SCS performed with increased accuracy. This demonstrates that physical therapists holding APTA certifications were more accurate with diagnosing than those who held any other specialty certifications. Having a certification other than an APTA certification increased accuracy for only the MRI diagnosis. This finding supports that physical therapists have recently had more exposure to MRI’s,8,16,30-32 which corresponds to the increased accuracy with the diagnosis of the MRI case.

Practice setting and patient population did not provide as robust of findings as seen above. The frequency of anterior cruciate ligament tears being seen in outpatient orthopedic setting could have contributed to the accuracy of respondents working in that practice setting. Although all three diagnoses were orthopaedic in nature, the anterior cruciate ligament tear is the most commonly seen.

Limitations There are limitations to this study. Although the researchers looked at primary physical therapy degree and highest degree earned years of experience or age of clinicians was not examined. The survey was only sent out to Ohio Physical Therapists for convenience and cost reasons; therefore, it is possible that the results of this survey are not representative of physical therapists across the country and world. The clinical vignettes were written by one of the authors. While the information included in the scenarios was taken from the literature, experts outside of the authorship team did not validate these scenarios. Only one imaging modality was chosen for each clinical scenario. Therefore, a conclusion cannot be drawn regarding the appropriateness of one imaging modality over another for each of the clinical scenarios. Finally, there is a test order effect.

The order of the cases was not randomized for each participant. On a whole, the accuracy rates declined for each subsequent case. It cannot be determined

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if this was due to a test order effect or the clinical scenario and images.

CONCLUSION Physical therapists ability to identify pathology on images greatly improves with a clinical scenario, although it is apparent that the clinical condition and imaging modality affects the accuracy of that diagnosis. In addition formal and informal training, board certification through the APTA and to a lesser extent, degree level, can also influence diagnostic accuracy, therefore demonstrating that education through a physical therapy curricula or later in forms of certifications and continuing education can prepare physical therapists for the increased utilization of imaging in the clinic for improved patient care.

REFERENCES 1. American Physical Therapy Association. Vision 2020. Available at: http://www.apta.org/ Vision2020/. Accessed December 17, 2013.

2. Threlkeld A, Jensen G. The Clinical Doctorate: A Framework for Analysis in Physical Therapist Education. Phys Ther [serial online]. June 1999;79(6):567. Available from: Academic Search Complete, Ipswich, MA. Accessed March 16, 2014.3.

3. Brudvig TJ, Colbeck CL. The doctor of physical therapy: clinical and academic physical therapists’ perception of appropriate curricular changes. l Phys Ther Educ. 2007;21(1):3-13.

4. Little T, Lazaro R. Physiotherapists’ perceptions and use of medical imaging information in practice.

Physiother res int. 2006;11(1):14-23.

5. McKinnis LN. Fundamentals of Musculoskeletal Imaging. 3rd ed. Philadelphia, PA: F.A. Davis Company; 2010.

6. Deyle GD. Musculoskeletal imaging in physical therapy practice. J Orthop Sports Phys Ther. 2005; 35(11): 708-720.

7. Threlkeld AJ, Paschal KA. Entry-level physical therapist education in the United States of America.

Phyl Ther Rev. 2007;12:156-162.

8. Greathouse DG, Schreck RC, Benson CJ. The United States Army physical therapy experience: evaluation and treatment of patients with neuromusculoskeletal disorders. J Orthop Sports Phys Ther 1994;19:261–6.

9. Boyles RE, Gorman I, Pinto D, et al. Physical therapist practice and the role of diagnostic imaging.

J Orthop Sports Phys Ther.2011; 41(11):829-837. doi:10.2519/jospt.2011.3556.

10. Garber MB Diagnostic imaging and differential diagnosis in 2 case reports. J Orthop Sports Phys Ther.

2005 Nov;35(11):745-54.

11. Boissonnault WG, Badke MB, Powers JM. Pursuit and implementation of hospital-based outpatient direct access to physical therapy services: an administrative case report. Physl Ther.

2010;90(1):100-109.

12. Daker-White G, Carr AJ, Harvey I, et al. A randomized controlled trial. Shifting boundaries of doctors and physiotherapists in orthopaedic outpatient departments. J Epidemiol Community Health. 1999 Oct;53(10):643-50.

13. McMeeken J. Physiotherapy education in Australia.

Phys Ther Rev. 2007;12:83-91.

14. Skinner MA. Physiotherapy education in New Zealand. Phys Ther Rev. 2007;12:122-128.

15. Murphy BP, Greathouse D, Matsui I. Primary care physical therapy practice models. J Orthop Sports PhysTher. 2005; 35(11):699-707.

16. Moore JH, Goss DL, Baxter RE, et al. Clinical diagnostic accuracy and magnetic resonance imaging of patients referred by physical therapists, orthopaedic surgeons, and nonorthopaedic providers.

J Orthop Sports Phys Ther. 2005; 35(2):67-71.

17. Loy C, Irwig L. Accuracy of Diagnostic Tests Read With and Without Clinical Information: A Systematic Review. JAMA [serial online]. October 6, 2004;292(13):1602-1609. Available from: Academic Search Complete, Ipswich, MA. Accessed March 16, 2014.

18. Donato EB, DuVall RE, Godges JJ, et al. Practice Analysis: Defining the clinical practice of primary contact physical therapy. J Orthop Sports Phys Ther.

2004; 34(6): 284-304.

19. Lucie RS, Fuller S, Burdick DC, et. al. Early prediction of avascular necrosis of the femoral head following femoral neck fractures. Clin Orthop Relat Res. 1981 Nov-Dec;(161):207-14.

20. Zibis AH, Karantanas AH, Roidis NT, et al, The role of MR imaging in staging femoral head osteonecrosis. Eur J Radiol. 2007 Jul;63(1):3-9. Epub 2007 Jun 6.

21. Barille MF, Wu JS, McMahon CJ. Femoral head avascular necrosis: a frequently missed incidental finding on multifactor CT. Clin Radio.l 2014;69(3):2805. doi: 10.1016/j.crad.2013.10.012. Epub 2013 Dec 2.

22. Wu, XY. Analysis of the causes of X-ray misdiagnosis of avascular femur head necrosis. Zhongguo Gu Shang. 2013 Feb;26(2):162-4.

23. Sugano N, Kubo T, Takaoka K. Diagnostic criteria for non-traumatic osteonecrosis of the femoral head. A multicenter study. JBJS. 1999;81(4):590-5.

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24. Takami M, Nohda K, Sakanaka J, et al. Usefulness of full spine computed tomography in cases of highenergy trauma: a prospective study. Eur J Ortop Surg Traumatol. 2013. doi: 10.1007/s00590-013-1268-0.

Epub 2013 Jul 6.

25. Rogers WA. Fractures and dislocations of the cervical spine: an end result study. J Bone Joint Surgery 1957; 39-A:341-76.

26. Blackmore CC, Emerson SS, Mann FA, et al. Cervical spine imaging in patients with trauma: determination of fracture risk to optimize use.

Radiology 1999;211(3);759-65.

27. Zabel DD, Tinkoff G, Wittenborn W, et al. Adequacy and efficacy of lateral cervical spine radiography in alert high-risk blunt trauma patient. J Trauma 1997;43:952–6 28. Utz M, Khan S, O’Connor D, et al. MDCT and MRI evaluation of cervical spine trauma. Insights Imaging.

2014 Feb;5(1):67-75. doi: 10.1007/s13244-013-0304-2.

Epub 2013 Dec 12.

29. Vahey TN, Meyer SF, Shelbourne KD et al. MR imaging of anterior cruciate ligament injuries. Magn Reson Imaging Clin N Am. 1994;2(3):365-80.

30. Benson CJ, Schreck RC, Underwood FB, et al. The role of Army physical therapists as nonphysician health care providers who prescribe certain medications: observations and experiences. Phys Ther 1995;75:380–6. [PubMed]

31. James JJ, Abshier JD. The primary evaluation of musculoskeletal disorders by the physical therapist.

Mil Med 1981;146:496–9. [PubMed] 32. James JJ, Stuart RB. Expanded role for the physical therapist. Screening musculoskeletal disorders. Phys Ther 1975;55:121–31. [PubMed] 33. Learman K, Showalter C, Cook C. Does the use of a prescriptive clinical prediction rule increase the likelihood of applying inappropriate treatments? A survey using clinical vignettes. Man Ther. 2012 Dec;17(6):538-43. doi: 10.1016/j.math.2012.05.011.

Epub 2012 Jun 21.

34. Childs JD, Whitman JM, Sizer PS, et al. A description of physical therapists’ knowledge in managing musculoskeletal conditions. BMC Musculoskeletal Disorders. 2005; 6(32). doi:10.1186/1471-2474-6-32..

35. Freedman KB, Bernstein J. The adequacy of medical school education in musculoskeletal medicine. J Bone Joint Surg. 1998; 80(10).1421-7.

36. Jette D, Ardleigh K, Chandler K, et al. DecisionMaking Ability of Physical Therapists: Physical Therapy Intervention or Medical Referral. Phys Ther [serial online]. December 2006;86(12):1619-1629.

Available from: Academic Search Complete, Ipswich, MA. Accessed March 16, 2014.

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APPENDIX 1 Survey *1. I am confident in my ability to interpret diagnostic imaging results on a(n) Strongly Agree

Agree

Disagree

Strongly Disagree

Plain Film Radiograph MRI CT Scan

*2. Please type a diagnosis based on the following images found for case 1.

Figure 1:

Figure 3:

Figure 2: *3. Given the same images and the following clinical information, please type in the correct diagnosis for this patient. The patient is a 16 year old who plays high school tennis. During a match one week ago, she approached the net to block a ball and fell to the ground with immediate left knee pain. The knee immediately swelled and she was unable to bear weight. The athletic trainer did an initial examination and recommended she go to the emergency room.

The emergency room physician had an xray taken which came back negative. He recommended rest, elevation and ice and to follow up with an orthopedic doctor or physical therapist that week. The patient was able to walk and felt “almost perfect” two days later. She was ready to get back to tennis; however, her parents made The International Journal of Sports Physical Therapy | Volume 9, Number 5 | October 2014 | Page 685

her see a physical therapist. The physical therapist had concerns. Although the patient stated she felt fine, she also admitted to buckling episodes a few times a day. The therapist realized the patient was extremely (maybe too) motivated to return to tennis as conferences were approaching. Due to her concerns, the physical therapist discussed further imaging with the patientâ&#x20AC;&#x2122;s physician and an MRI was ordered.

Figure 5:

*4. Please type a diagnosis based on the following images found for case 2.

Figure 4:

Figure 6:

*5. Given the same images and the following clinical information, please type in the correct diagnosis for this patient.The patient is a 52 year old male with a history of a MVA six months ago. He went to the ER immediately following The International Journal of Sports Physical Therapy | Volume 9, Number 5 | October 2014 | Page 686

the accident and was sent home. Six months later he is experiencing pain bilaterally through his neck and shoulders which he describes as a 6/10 on the visual analog scale. He states his pain is daily and feels like a constant throb. He has come to physical therapy for evaluation and treatment of what he describes as whiplash.

The physical therapist does not note any myelopathic signs, no decreases in strength, but there are decreased reflexes in his upper extremities and decreased cervical range of motion. The PT is hesitant to continue with this patient based on the history of the MVA and constant pain since. He recommends an appointment with his PCP to rule out any contraindications to physical therapy. The PCP ordered an X ray which showed abnormal alignment so a CT was ordered for further investigation.

Figure 8:

*6. Please type a diagnosis based on the following images found for case 3.

*7. Given the same images and the following clinical information, please type in the correct diagnosis for this patient.The patient is a 50 year old male who has sickle cell anemia. He has a two yearold granddaughter who he watches for a few hours a day, three days a week. Three months ago he came to your clinic because he started to have pain in his right hip with weight bearing activities, and this was making it difficult to watch his granddaughter. Now, three months later his pain is continuing to increase with activities, but he also notes pain with lying in bed. He use to describe his pain as dull, achy pain and now he says it feels like its shooting down his thigh and into is groin. He has become stiff and is demonstrating decreased ROM in his hip. He is expressing frustration since he is â&#x20AC;&#x153;getting worseâ&#x20AC;? and can no longer watch his granddaughter without being in more pain. The PT recommends he follow up with his PCP since he does not appear to be getting any relief from physical therapy. His PCP sent him for a plain film radiograph.

Figure 7:

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*8. What is the highest earned degree you hold in any area of study? (Select one) ❍ Baccalaureate degree ❍ Master’s degree ❍ PhD (or equivalent, e.g. EdD or ScD) ❍ DPT ❍ tDPT ❍ PhD (or equivalent) and DPT ❍ PhD (or equivalent) and tDPT ❍ Other (please specify) *9. What was your first (entrylevel) physical therapy degree, prior to taking the licensure exam? ❍ Baccalaureate degree ❍ Post baccalaureate certificate ❍ Masters degree ❍ DPT ❍ Other (please specify) *10. Have you received education in diagnostic imaging? Please check all that apply. ❍ Requirement for an entry level PT degree ❍ Requirement for a post professional degree ❍ Taken as a continuing education course ❍ Other (please specify) _____________________ *11. Have you earned any of the following certifications? Please check all that apply. ❍ CCS ❍ ECS ❍ GCS ❍ OCS ❍ PCS ❍ NCS ❍ SCS ❍ Other (please specify) _______________________ ❍ WCS ❍ FAAOMPT ❍ MDT ❍ COMT ❍ CIMT ❍ MTC

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*12. Using a total of 35 or more hours per week (at your primary position) as the definition of ‘fulltime’, which one of the following describes your current employment status? ❍ Fulltime ❍ Parttime ❍ PRN ❍ Retired ❍ Unemployed/not seeking work ❍ Unemployed/seeking fulltime employment ❍ Unemployed/seeking parttime employment ❍ Other (please specify) _______________________________ *13. Which of the following best describes the type of facility or institution in which you currently do all or most of your work (your primary position)? ❍ Acute care hospital ❍ Subacute rehab hospital (inpatient) ❍ Health system or hospitalbased outpatient facility or clinic ❍ Private outpatient office or group practice ❍ SNF/ECF/ICF ❍ Patient’s home/home care n ❍ School system (preschool/primary/secondary) ❍ Academic Institution (postsecondary) ❍ Health and Wellness Facility ❍ Research Center ❍ Industry ❍ Other (please specify) ________________________________ *14. What percentage of your patients have an orthopaedic condition? ❍ 025% ❍ 2650% ❍ 5175% ❍ 76100% ❍ Not applicable *15. Which type of courses do you teach? Please check all that apply. ❍ Orthopaedic ❍ Diagnostic Imaging ❍ Not applicable ❍ Other (please specify) ___________________________

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*16. How often do you view patient images? ❍ 0% of patients ❍ 110% of patients ❍ 1125% of patients ❍ 2650% of patients ❍ 5175% of patients ❍ 7699% of patients ❍ 100% of patients ❍ Not applicable *17. How often do you view Very Frequently

Frequently

Infrequently

Very Infrequently

Not Applicable

Plain Film Radiographs Plain Film Radiograph Reports MRI MRI Reports CT Scan Images CT Scan Reports *18. I always use imaging information when available. ❍ Strongly agree ❍ Agree ❍ Disagree ❍ Strongly disagree ❍ Not applicable

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IJSPT

CASE REPORT

UTILIZATION OF AUTOREGULATORY PROGRESSIVE RESISTANCE EXERCISE IN TRANSITIONAL REHABILITATION PERIODIZATION OF A HIGH SCHOOL FOOTBALL-PLAYER FOLLOWING ANTERIOR CRUCIATE LIGAMENT RECONSTRUCTION: A CASE REPORT Aaron D. Horschig, DPT, CSCS, USAW1 Travis E. Neff PT, ATC, CSCS1 Ambrose J. Serrano, MA, CSCS, USAW2

ABSTRACT Background and Purpose: The Autoregulatory Progressive Resistance Exercise (APRE) model of periodization is an effective form of resistance training programming for short-term training cycles in healthy athletic populations that has yet to be effectively described in literature in application for rehabilitation purposes. The purposes of this case report are to: 1) review the periodization concepts outlined in the APRE model, 2) to detail the use of the APRE periodization programming through the rehabilitation of a high school football player using the back squat exercise after anterior cruciate ligament reconstruction (ACLR) and 3), to examine the applicability of this method in the transitional period from skilled rehabilitation to strength and conditioning for which a current disconnect exists.

Case Description: Starting at 20 weeks post-operatively, a 17-year-old male high school football player recovering from ACLR was able to show a 10 lb daily average increase with the 10 RM protocol, a 6 lb daily average increase during the 6RM protocol, and a 6.3 lb average increase with the 3RM protocol.

Outcomes: A two-repetition maximum of 390 lbs was performed in the back squat at the conclusion of the program at 39 weeks post-operatively.

Discussion: The results of this case report strengthen the current limited knowledge regarding periodization during the later phases of rehabilitation and the transition back to sport participation time period, while at the same time providing new insights for future protocol considerations in rehabilitating athletes.

The APRE method of periodization provides an individualized progressive resistive protocol that can be used to safely and effectively increase strength in both healthy populations and individuals recovering from injury during short-term training cycles.

Levels of Evidence: Therapy, Level 4-Case report Key Words: Back squat, periodization, physical therapy

1

Boost Physical Therapy & Sports Performance, Lee’s Summit, MO, USA 2 Lake Placid Olympic Training Center, Lake Placid, NY, USA

CORRESPONDING AUTHOR Aaron D. Horschig, DPT, CSCS, USAW Physical Therapist at Boost Physical Therapy & Sports Performance 1254 SE Century Drive Lee’s Summit, MO 64081 (314) 704-0546 Fax: (816) 524-1445 E-mail: Aaron@boostkc.com

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BACKGROUND AND PURPOSE The concept of periodization, defined as a systematic planned variation of program variables in a training program, has been well established in literature to be more effective in eliciting strength, body composition improvements and other performance goals than non-periodized programs both in healthy, injured, trained, and untrained individuals.1,2,3,4,5,6 Synonymous with phrase “Training Organisation,” the utilization of periodization is not a recent development, with many texts on the subject appearing as early as 1917.7 A periodized program optimizes the principles of “specific adaptation to imposed demands” (SAID) and the “progressive resistance method” (PRE) in order to more efficiently promote desired outcomes such as increased strength or muscular hypertrophy through the continual adaptation responses of the neuromuscular system.7,8 By introducing progressively overloading stressors to the body, the neuromuscular system will adapt and develop towards the targeted fitness goals, provided the systematic progressing load stressors are adequate and do not exceed the adaptive capabilities of the body.7 However, once the body has adapted to the added stressor, strength increases are no longer seen.8 Simply stated, periodization continually changes the type of stressors placed on the neuromuscular system, thereby avoiding a plateau and promoting continued adaption and strength gains.

An early training programming model used to systematically improve strength was reported in literature in 1945 by DeLorme, who proposed a method consisting of multiple sets in which patients lifted their 10 repetition maximum (RM).9 Eventually this protocol evolved to a three set system of progressing heavier loads for 10 repetitions; referred to as progressive resistance exercise (PRE).9 This has since been the starting point for the development and study of numerous periodization concepts such as classical linear periodization (LP), which emphasizes a breakdown of the training program into time periods or training cycles of macrocycles (9-12 months), mesocycles (3-4 months) and microcycles (1-4 weeks) with ever fluctuating changes in volume and intensity.8,10,11 Other popular forms of non-linear periodization include undulating models, as described by Poliquin, in which programming variables such as volume and intensity are changed more frequently

such as on a daily or weekly basis.12 The concept of Daily undulating periodization (DUP) has been shown to elicit greater strength gains in short-term training cycles (12 weeks) when compared to LP models equated for similar volume and intensity.8,13 Although there is a consensus in the literature on benefits of periodized vs non-periodized programming when it comes to eliciting the most efficient strength and performance gains, large inconsistencies remain regarding which type of periodized model is most efficient. 14 This dilemma is even more complicated when taking into account the training level of the subject and time frame allowed for training programming. An even greater gap in evidence exists in periodization protocols that are specific for the injured and rehabilitating athlete that facilitate the most efficient neuromuscular adaptations while being mindful of the healing processes taking place at the biological level.15 Most literature on strength training periodization is based on healthy and not rehabilitating subjects.15 Current popular protocols for rehabilitation periodization emphasize the principles of DeLorme’s PRE through LP and non-linear protocols.15,16 Complicated with the common inability to assess a patient’s 1 repetition maximum (1RM) secondary to rehabilitation contraindications, especially post-operatively, many clinicians are left with presupposed approaches for determining the appropriate program variables to facilitate maximal efficient performance gains. Even after discharge from rehabilitation, many practitioners and strength and conditioning coaches often resort to using a “bestguess” approach during the transition period where a subject is no longer injured or in need of skilled rehabilitation, however, is not yet displaying his or her pre-injury strength and still re-acquiring strength through neuromuscular adaptations at a different rate than healthy subjects. These athletes are many times blindly thrust back into their prior training programs with little attention given towards a needed personalized individualized periodized protocol. The quick return to prior training programs is many times based on a flawed premise that the athlete, once given the “cleared” medical status, is without question ready to resume their exact high-level prior training regime.

It was not until 1979 when a variant of the DeLorme system, known as the Daily Adjustable Progressive

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Resistance Exercise (DAPRE) method, was successfully integrated into rehabilitation programming by Knight.17 This method allowed, for the first time, an interactive protocol to objectively determine either the optimal time to increase resistance or the optimal amount of weight to increase the resistance during a resistance exercise, thus providing a more efficient way to rehabilitate strength by accounting for individualized reacquisition of strength.2 A specific autoregulatory program by Siff, derived from the DAPRE method, expanded on this concept in order to meet different training goals of hypertrophy and strength/power, and allow for continual body adaptation through the SAID principle.7 This method, termed Autoregulatory Progressive Resistance Exercise (APRE), enhances the previous DAPRE method by introducing training cycles aimed at improving hypertrophy, strength and power regimes of conditioning. This allows for continual neuromuscular adaptation to systematically changing program variables thus promoting efficient performance gains.7 To the authors’ knowledge, only one study has compared the effectiveness of the APRE method to another periodization model. When compared to a traditional LP model, the APRE method of periodization has been shown to be more effective in increasing the strength and strength-endurance of healthy subjects in both the bench press and squat over a short period of 6 weeks.14 There is, however, no evidence in literature supporting or documenting the use or effectiveness of the APRE concept during the rehabilitation process of the injured athlete.

The purposes of this case report are to: 1) review the periodization concepts outlined in the APRE model, 2) to detail the use of the APRE periodization programming through the rehabilitation of a high school American football player using the back squat exercise after anterior cruciate ligament reconstruction (ACLR) and 3), to examine the applicability of this method in the transitional period from skilled rehabilitation to strength and conditioning for which a current disconnect exists.

Case Description The patient was an active 17-year-old male American high school football player with a history of ACLR of his dominant right lower extremity. Mechanism

for original injury was a non-contact deceleration and pivot movement during a football game. Magnetic resonance imaging (MRI) of the lower extremity revealed a complete anterior cruciate ligament (ACL) rupture. The patient completed initial conservative rehabilitation and was able to return to finish his season wearing a functional knee brace until eventually undergoing ACL reconstruction surgery using a bone – patellar tendon – bone (BTB) autograft along with a partial lateral meniscectomy, after the end of the season. Time from initial injury to date of surgery was approximately 15 weeks. During his return to football before ACL reconstruction surgery, the patient had no reported episodes of giving-way however reported feeling unstable and weak during single leg tasks. The patient’s post-operative rehabilitation process was unremarkable without any complications utilizing traditional evidence-based rehabilitation clinical protocol guidelines.18 Criteria during early phase rehabilitation included restoring knee active range of motion (AROM), quadriceps strengthening (both with isometric and closed chain kinetic exercises, such as mini-squats), restoring patellar mobility, diminishing swelling and pain, and restoring safe independent ambulation. Later phases of rehabilitation continued the trend towards increasing intensity and complexity of functional strengthening while incorporating strength and conditioning principles such as power development, balance and proprioception training. He received medical release to return to running at 16 weeks post-operatively and was able to return to full athletic participation by 30 weeks. For the purpose of this case report, the details of his rehabilitation protocol other than the APRE programming for the back squat exercise, which began at 20 weeks post-operatively, are not included, as the entirety of the rehabilitation process is not the specific focus of this case report. Informed consent was obtained from the subject indicating approval for data collection for the purpose of publication.

Clinical Impression #1 It was determined that the patient was a good choice to utilize the APRE intervention secondary to the need to return to his prior high level of strength in an efficient manner. Because he was a high school football player he would be required to perform high intensity squats during team strength and conditioning sessions

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and up until this point he had only performed very light intensity squats during rehabilitation exercises with higher repetitions. Prior to the start of the APRE periodization, the patient had been progressing from squats while holding a weighted kettle bell (45 lbs) for 3-5 sets of 15-20 repetitions and had transitioned to using the weightlifting bar for back squats of light intensity (135 lbs) for 3-5 sets of 10 repetitions. For this reason an efficient method of strength periodization was needed in order to help the patient return to higher intensity squatting.

Examination At 20 weeks post-operatively the patient was able to meet the developed criteria for initiation of the APRE program, including observed lower extremity symmetry within 90% (ACLR compared to opposite lower extremity) using the 1) Star Excursion Balance Test (SEBT) and 2) a lateral step down excursion test.19,20 The SEBT has been shown to be an effective test in analyzing postural and lower extremity control deficits.20 The patient also had to demonstrate correct technique in the barbell back squat.21 It is important to note that any lower extremity symmetry of less than 90% compared to the opposite lower extremity would prohibit the start of the APRE program for the reason that a considerable amount of skilled therapy to enhance neuromuscular control would still be needed before progressing to a protocol that emphasizes strength/power.

The back squat method utilized during the protocol was a high bar technique with shoulder width stance.

The athlete was given verbal and tactile cues to slowly descend to a parallel position where the hip and knee joints were even, and then extending the hips and knees simultaneously during the ascension phase without leaning forward or showing unwanted hip rotation.

The athlete wore only standard cross-training shoes and did not wear any additional supporting equipment during any of the squatting sessions such as belts, lifting suits, knee wraps, or weightlifting shoes.

Clinical Impression #2 Based on the patients ability to show sufficient lower extremity symmetry on all examination testing previously discussed, it was determined that he met the requirements to start the APRE periodization for the back squat exercise at 20 weeks post operative.

Outcome The APRE method employs a 10 RM scheme for hypertrophy, a 6 RM scheme for strength/hypertrophy, and finally a 3 RM scheme for strength/power.7 All routines are based on the DeLorme method of PRE and consist of 4 sets of different load and repetition requirements (Table 1).7 The 10 RM regime will be described here as it was the first periodization scheme employed for this case report for the back squat exercise. After the performance of a general warm up including 10 minutes cycling on a recumbent bike followed by 5 minutes of self-myofascial release using foam rolling to the anterior and lateral lower extremities, the first set consisted of 12 repetitions at 50% of the estimated 10 RM (also labeled the working set as the first two sets are percentages taken from set 3). After a minimum 2-minute rest period, the first set was followed by 10 repetitions at 75% of the same-estimated 10 RM. During the third set, the anticipated 10 RM was lifted until failure. Due to this programming being used for rehabilitation and transition purposes, failure was not only seen as the inability to complete another repetition, but also the inability to continue with good technique secondary to lower extremity compensations or the presence of pain. For this reason, the clinician overseeing the performance at times made subjective decisions to end the set secondary to technique deficits that began to appear. The number of repetitions reached during this maximal effort third set was then used to adjust the intensity for the fourth and last set (Table 2). Again, repetitions during the fourth set were performed to maximum effort, and the number of repetitions reached was used similarly after the previous third set in order to determine the anticipated 10 RM â&#x20AC;&#x153;working setâ&#x20AC;? for the next training session by adding or subtracting loads (Table 2). This allows subjects to

Table 1. Adjusted Progressive Resistance Exercise Training Routines.

Set 0 1

3 RM Routine Warm-up 6 reps (50% of 3 RM)

6 RM Routine Warm-up 10 reps (50% of 6 RM)

10 RM Routine Warm-up 12 reps (50% of 10 RM) 2 3 reps (75% of 3 RM) 6 reps (75% of 6 RM) 10 reps (75% of 10 RM) 3 Reps to failure (3 RM) Reps to failure (6 RM) Reps to failure (10 RM) 4 Adjusted reps to failure* Adjusted reps to failure* Adjusted reps to failure* *Denotes that the training load must be adjusted according to Table 2

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Table 2. Example Adjustments for APRE Protocols.

Adjustments for 3 RM Repetitions Set 4 1-2 Decrease 510 lbs 3-4 Same 5-6 7+

Adjustments for 6 RM Repetitions Set 4 0-2 Decrease 510 lbs 3-4 Decrease 05 lbs 5-7 Same

Increase 510 lbs Increase 10- 8-12 15 lbs 13+

Increase 510 lbs Increase 10-15 lbs

Adjustments for 10 RM Repetitions Set 4 4-6 Decrease 510 lbs 7-8 Decrease 05 lbs 9-11 Same 12-16 17+

Increase 510 lbs Increase 10-15 lbs

exercise near their optimal capacity for strength during each training session allowing for individualized progression of strength redevelopment.2 It should be noted that rest periods between sets are subjective based on the patients perceived fatigue. It is recommended by the authors that a minimum 2 minutes of rest, maximum of 5 minutes, be utilized between the maximum repetition sets.

The 10 RM scheme was used during 6 training days over a 3-week period, each spaced at least 2 days apart for adequate recovery. For the purpose of this case report, strength changes seen during the APRE protocol are reported as the performance changes seen between the first and last day of each separate repetition protocol (Figure 3). After the 3-week protocol was complete, a de-loading week was employed consisting of 3 sets of 10 repetitions at 75% of the last estimated 10RM for two training sessions. The 6RM protocol was then initiated for a 3-week period, again consisting of 6 training periods spaced at least 2 days apart. The second

de-load week was employed after finishing the 6RM protocol, this time consisting of 3 sets of 5 repetitions at 75% of the last 6RM estimate. The last 3RM scheme of the APRE used a 3-week cycle with 5 training sessions. Overall, the APRE program was able to emphasize 3 distinct phases of hypertrophy, strength/hypertrophy, and strength/power (Table 4). At no time during the protocol did the athlete experience pain, which would have limited his ability to perform continued repetitions.

Table 3 contains tabulated results for the back squat performance changes seen with the APRE. Through the 10RM protocol, a 50 lb increase in strength was shown (21.3% improvement) in a 3-week period consisting of 6 workouts. A daily average increase of 10 lbs was seen (4.3% improvement) with a weekly average increase of 17.5 lbs with the 10 RM protocol.

During the 6RM protocol, a 30 lb increase was seen (9.7% improvement) in a 3-week period consisting of 6 workouts. A daily average increase of 6 lbs (1.9% improvement) was shown with a weekly average increase of 12.5 lbs (4% improvement). During the 3 last weeks of the APRE program, the 3RM protocol yielded a 25 lb increase (6.9% improvement) over 5 workouts. A 6.3 lb daily average increase (1.7% improvement) was shown with a 13.8 lb weekly average increase (3.8% increase). The last day the patient was able to perform a 390 lb back squat for 2 repetitions 32 weeks post-op ACLR. This weight of 390 lbs was only 100 lbs less than his prior 1 repetition maximum prior to tearing his ACL.

Table 3. APRE Repetition and loads for Subject.

APRE Rep Scheme

Number of Sessions

First Day

Last Day

Strength Increases (4th Set)

3rd Set

4th Change Set (%)

Daily Average (lbs)

Change (%)*

Weekly Average (lbs)

Change (%)*

10

4.3

17.5

7.4

6

1.9

12.5

4

6.3

1.7

13.9

3.8

4th Set

10 RM 6 Weight (lbs) 225 235 285 21.3 Repetitions 15 10 10 6 RM 6 Weight (lbs) 300 310 340 9.7 Repetitions 10 6 5 3 RM 5 Weight (lbs) 370 365 390 6.8 Repetitions 2 0 2 *Denotes change from the irst day weight lifted

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Table 4. Overall APRE Training Program with associated phase empahsis

APRE Rep Active Weeks Emphasis of Phase Scheme 10 RM 1,2,3,4* Hypertrophy 6 RM 5,6,7,8* Strength/Hypertrophy 3 RM 9,10 Strength/Power * Weeks 4 & 8 were de-load weeks, but still performed the repetitions designated in the speci ic phase

DISCUSSION The concept of periodization, defined as a systematic planned variation of program variables in a training program, has been well established in literature to be more effective in eliciting strength, body composition improvements and other performance goals than non-periodized programs both in healthy, injured, trained or untrained individuals.1,2,3,4,5,6 There is abundant literature on periodization protocols and their effectiveness in healthy trained and untrained subjects as it relates to all aspects of fitness, not only strength. However a paucity of evidence can be found in relation to rehabilitation protocols, especially when searching for protocols for effective and safe ways to return an athlete to a high level of sport and resistance training performance post-operatively.

Consistency in descriptions of specific programming variables is lacking amongst clinical protocols in which effective rehabilitation can be carried out while still being mindful of individual differences in biological and neuromuscular healing processes.15,22 Rehabilitation periodization protocols exist outlining both linear and non-linear programming approaches, which make good recommendations for exercise selection and even volume, however, they lack in specifics for exercise intensity.15 For example, with the linear periodization following ACL reconstruction proposed by Lorenz et al, the protocol load requirements are generally vague per volume requirements, and may not be as effective for that reason in promoting the reacquisition of strength in power athletes that need to return to high intensity resistance exercises such as the back squat.15 The DeLorme protocol of PRE was the first reported periodization model in research literature to detail a systematic model for increasing strength both in healthy and injured populations.9 The DAPRE method

by Knight, modified from the original DeLorme PRE, allowed for the first time an interactive protocol for objectively determining either the optimal time to increase resistance or the optimal amount of weight to increase the resistance during an exercise, thus providing a more efficient way to rehabilitate strength in an individualized and safe manner.2 The APRE used in the present case report, varies only slightly from the DAPRE in that it provides multiple training protocols within itself based on specific desired outcomes.

There is a 10 RM scheme provided for improving hypertrophy, a 6 RM scheme for addressing strength/ hypertrophy, and finally a 3 RM scheme for development of strength/power.7 In a rehabilitation setting or in a strength and conditioning setting for the transition athlete who has been discharged from a traditional rehabilitation setting however has not yet returned to pre-injury strength levels, this allows for continual neuromuscular adaptation to systematically changing program variables thus promoting efficient performance gains.7 Where as the DAPRE method has only been shown in literature with non-functional seated knee extension strengthening exercises after knee injury, the APRE method has been shown in healthy populations to be an effective periodization method when used with functional strengthening exercises such as the back squat compared to LP programming during short (6 week) training programs.2,14 Mann et al was able to show significant improvements in 1RM bench press, number of repetitions performed with a weight of 225 lbs in the bench press (strength/endurance) and in estimated 1RM back squat (APRE: 43.3 +/- 23.2 lbs vs LP 8.4 +/- 34.8 lbs, p = 0.05) compared to a LP group over a 6-week training period.14 The results of this case report are consistent with the findings of Mann et al, showing significant changes in estimate RM back squat strength using the APRE protocol in a short training cycle (Table 3).14 The APRE protocol used in this case report allowed for weeks of de-loading between the three stages. This principle of using de-loading weeks, called the fluctuating overload system, has been used to facilitate recovery and growth between stages of increased loading of a microcycle.7 It has been recommend that if maintaining a LP program model during the rehabilitation after ACLR, strength training should be the emphasis between the

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12th to 16th week before employing the power phase in the later weeks of the rehabilitation process.15 For the authorsâ&#x20AC;&#x2122; purposes, the APRE programming regime for the back squat was not incorporated into the rehabilitation protocol until the 20th week post-operatively. The 20th post-operative week was deemed, in the authors opinion, to be an important transitional period when the patient had been medically released to return to partial participation in athletics and weight training, yet had not re-acquired strength levels prior to ACLR. The athlete had been utilizing numerous forms of resisted squatting exercises in the rehabilitation protocol such as hand-held kettle bell squats and band resistance squats up until the point when the APRE was initialized. It is important to note some physician post-operative protocols restrict strengthening of the involved lower extremity for many weeks, thus, the initiation of the APRE protocol would need to be delayed until proper prerequisites for the start were met.

There are several limitations to this case report; one being that the results are only based on the strength increases of one patient during the rehabilitation process. More research should be performed with patients rehabilitating from similar injuries with a control group of athletes using other LP or DUP programs in order to fully assess the effectiveness of each protocol. The results of this case report do not suggest that the APRE protocol is superior to LP or DUP programming, however show that strength can be gained in a healthy individual and re-acquired during rehabilitation and in the transition phase after formal rehabilitation in a quick and safe manner during short-term training cycles.

Conclusion During the transition period after skilled physical rehabilitation, athletes may find themselves returning to resistance training with strength deficits compared to pre-injury levels. This results of this case report demonstrate the outcomes following the use of a detailed, individualized periodized protocol that was used safely and effectively for this athlete in a rehabilitation and transition period in order to increase his back squat performance in a short time period.

REFERENCES 1. Baker D, G. Wilson, & Carolyn R. Periodization: The effect on strength of manipulating volume and intensity. J Strength Cond Res. 1994;8:235-242.

2. Knight K. Quadriceps strengthening with the DAPRE technique: case studies with neurological implications. Am College of Sports Med. 1985;17(6): 646-650 3. Stone, MH, Oâ&#x20AC;&#x2122;Bryant H, & Garhammer J. A hypothetical model for strength training. J Sports Med Phys Fitness. 1981;21:342-351.

4. Stone MH, Oâ&#x20AC;&#x2122;Bryant H, Garhammer J, McMillan J, & Rozenek R. A theoretical model of strength training.

Strength Cond J. 1982;36-39.

5. Stowers, T., McMillan J., Scala D., Davis, V., Wilson, D., & Stone, M. The short-term effects of three different strength-power training methods. Strength Cond J. 1983;5:24-27.

6. Willoughby DS. The effects of meso-cycle length weight training program involving periodization and partially equated volumes on upper and lower body strength. J Strength Cond Res. 1993; 7:2-8.

7. Siff MC. Supertraining. Denver, Co: Supertraining Institute; 2000 8. Rhea MR, Ball SD, Phillips WT, & Burkett LN. A comparison of Linear and Daily Undulating Periodized Programs with Equated Volume and Intensity for Strength. J Strength Cond Res. 2002;16(2):250-255 9. Rhea MR, Phillips WT, Burkett LN, et al. A comparison of linear and daily undulating periodized programs with equated volume and intensity for local muscular endurance. J Strength Cond Res. 2003;17:82-87.

10. Baechle T & Earle R. Essentials of Strength Training and Conditioning. Champaign, IL: Human Kinetics, 2000.

11. Rhea MR, Phillips WT, Burkett LN, et al. A comparison of linear and daily undulating periodized programs with equated volume and intensity for local muscular endurance. J Strength Cond Res. 2003;17:82-87.

12. Poliquin C. Five steps to increasing the effectiveness of your strength training program. Strength Cond J. 1988;10:34-39 13. Prestes J, Frollini AB, De Lima C, et al. Comparison between linear and daily undulating periodized resistance training to increase strength. J Strength Cond Res. 2009;23(9):2437-2442 14. Mann JB, Thyfault JP, Ivey PA, & Sayers SP. The Effects of autoregulatory progressive resistance exercise vs linear periodization on strength improvements in college athletes. J Strength Cond Res. 2010;24(7):1718-1723 15. Lorenz DS, Reiman MP, & Walker JC. Periodization: Current Review and Suggested Implementation for

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Athletic Rehabilitation. Sports Health. 2010;2(6):509518 16. Reiman MP, Lorenz DS. Integration of strength and conditioning principles into a rehabilitation program.

Int J Sports Phys Ther. 2011;6(3):241-253 17. Knight K. Knee rehabilitation by th daily adjustable progressive resistive exercise technique. Amer J Sports Med. 1979;7(6): 336-337.

18. Wilk KE, Macrina LC, Cain EL, Dugas JR, & Andrews JR. Recent advances in the rehabilitation of anterior cruciate ligament injuries. J Orthop Sports Phys Ther.

2012;42(3):153-171 19. Chmielewski TL, Hodges MJ, Horodyski M, Bishop MD, Conrad BP, & Tillman SM. Investigation of clinician agreement in evaluating movement quality during unilateral lower extremity functional tasks: a

comparison of 2 rating methods. J Orthop Sports Phys Ther. 2007;37(3) 122-129 20. Herrington L, Hatcher J, Hatcher A, & McNicholas M. A comparison of star excursion balance test reach distances between ACL deďŹ cient patients and asymptomatic controls. The Knee. 2009;16:149-152 21. Fortin JD & Falco FJ. The biomechanical principles of preventing weightlifting injuries. Physical Medicine and Rehabilitation: State of the Art Reviews. 1997;11(3) 697-716 22. Beynnon BD, Uh BS, Johnson RJ, et al. Rehabilition after anterior cruciate ligaement reconstruction: a prospective, randomized, double-blind comparisoin of programs administered over two different time intervals. Am J Sports Med. 2005;33:347-359.

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IJSPT

CASE SERIES

TREATMENT OF NONSPECIFIC THORACIC SPINE PAIN WITH TRIGGER POINT DRY NEEDLING AND INTRAMUSCULAR ELECTRICAL STIMULATION: A CASE SERIES Jodie M. Rock, PT, DPT, OCS, FAAOMPT1 Charles E. Rainey, PT, DSc, DPT, OCS, SCS, FAAOMPT1

ABSTRACT Study Design: Case Series.

Background and Purpose: Myofascial trigger points (MTrPs) are a common occurrence in many musculoskeletal issues and have been shown to be prevalent in both subjects with nonspecific low back pain and whiplash associated disorder. Trigger point dry needling (DN) has been shown to reduce pain and improve function in areas such as the cervical and lumbar spine, shoulder, hip, and knee, but has not been investigated in the thoracic spine. The purpose of this case series was to document the use of DN with intramuscular electrical stimulation (IES) in subjects with nonspecific thoracic spine pain.

Case Description: The subjects were both active duty military males aged 31 and 27 years who self-referred to physical therapy for thoracic spinal pain. Physical examination demonstrated thoracic motor control dysfunction, tissue hypertonicity, and tenderness to palpation of bilateral thoracic paraspinal musculature in both subjects. This indicated the presence of possible MrTPs. Objective findings in the first subject included painful thoracic flexion and bilateral rotation in each of these planes of movement.

Pain reduction was observed when postural demands of the spine and trunk musculature were reduced through positional changes.

Patient 1 demonstrated pain with posterior to anterior (P/A) pressure at T9 to T12. The second subject had bilaterally limited and painful thoracic rotation actively with normal passive rotation and demonstrated pain with P/A pressure at T4 to T7.

Intervention: The subjects were treated with DN and IES for a total of two visits each. DN was performed to paraspinal and multifidus musculature at the levels of elicited pain with P/A testing and IES set at a frequency level of 4 (1.5Hz) for 20 minutes.

Outcomes: Subject 1 reported reduced pain with standing flexion from a 62mm VAS score on initial evaluation to 26mm at his second visit. Subject 2 reported being “quite a bit better” in symptoms on the GROC following his second treatment. His VAS score reported following weightlifting activities changed from 43mm on initial evaluation to 20mm at his second visit. Both subjects also demonstrated a 10 degree improvement in active thoracic spinal rotation (on the right for Subject 1 and bilateral for Subject 2) following their second treatment.

Discussion: Both subjects demonstrated motor control dysfunctions and pain with P/A pressure in the thoracic spine. With the use of DN and IES, immediate reduction was seen in subject perceived symptoms, and pain free ROM was improved. Extended treatment and follow up was not plausible due to the high pace tempo and demands of their operational training schedule. With research indicating the influence of MTrPs on a multitude of musculoskeletal issues and the prevalence of thoracic spine pain, further research is indicated for examining the effects of DN and IES for motor control and painful conditions occurring in the thoracic spine.

Level of Evidence: Level 4 Key Words: Dry needling, intramuscular electrical stimulation, myofasical trigger points, thoracic spine pain

1

Naval Special Warfare Group ONE, San Diego, CA, USA

The project was not required to be reviewed or approved by a US Navy Institutional Review Board.

Disclaimer The opinions or assertions contained herein are the private views of the authors and are not to be construed as official or as reflecting the views of the Department of the Navy or Department of Defense.

CORRESPONDING AUTHOR Charles E. Rainey 2922 W Canyon Ave San Diego, CA 92123 E-mail: raineychuck@hotmail.com

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BACKGROUND AND PURPOSE The prevalence of thoracic spine pain (TSP) has been reported to range from 3 to 22% in the general population.1 Rates of thoracic spine pain in varying professions have shown a lifetime prevalence of 77% in healthcare professionals and a one year prevalence’s of 55% and 54.8% in performing artists and manual laborers respectively.2 TSP can be a debilitating condition with many possible causes, including osteoporosis, hyperkyphosis, ankylosing spondylitis, and degenerative changes, as examples.3 While TSP may have a variety of causes, the results of a study performed by Wood et al4 indicates that it may also be nonspecific. Wood et al4 examined thoracic MRIs of 99 asymptomatic individuals and found that 73% were positive for anatomic pathology in one or more thoracic levels. These results indicate that anatomic pathology in many cases may not be a pain generator and that TSP may be more nonspecific much like how low back pain has been reported in the literature.

Myofascial Pain Syndrome (MPS) may play a role in nonspecific spine pain, and is a well-recognized and common cause of pain.5,6 Prevalence of MPS ranges from 21-85% in subjects with regional pain complaints7 and is defined as sensory, motor, and autonomic symptoms, arising from myofascial trigger points (MTrPs).8 A MTrP is a tender spot in a muscle often with a palpable taut band of tissue that elicits pain referral when pressure is applied.6,9 Active MTrPs refer pain that is “recognized” by the subject, while a latent trigger point has increased muscle tension and shortening but does not elicit spontaneous pain.10 MTrPs can be found in many muscles, which can contribute to various musculoskeletal problems, such as joint dysfunction, tendonitis, craniomandibular dysfunction, tension headaches, radiculopathies, and disk pathologies.5 Specifically related to the spine, it has been found that individuals with nonspecific chronic low back pain have greater number of trigger points, associated with higher pain levels and worse quality sleep than the general population.11 Compared to the general population, a greater number of trigger points were also found in a population of subjects with whiplash associated disorders (WAD) and the number of trigger points was related to pain intensity.12

It is theorized that MTrPs may be caused by sustained muscle contractions at low levels,13 muscle overload,10 unaccustomed concentric and eccentric contractions,14 low load repetitive tasks, and sustained postures.13,15,16 Increased end plate noise and excessive release of acetylcholine is found in active MTrPs which causes sustained muscle contractions leading to an ischemic and hypoxic environment.13, 14, 17-19 This ischemic and hypoxic environment leads to decreased pH which is capable of exciting nociceptors.13,20-23 Along with decreased pH, an increases in Substance P, calcitonin-gene-related peptide (CGRP), bradykinin (BK), serotonin (5-HT), norepinephrine, tumor necrosing factor-alpha, and interleukin-1 beta have been seen in active MTrPs which also contribute to sensitization and stimulation of nociceptors located within the muscle.13,21-23 This stimulation of nociceptors from active trigger points may cause peripheral and central sensitization through continued nociceptive signals to the dorsal horn and therefore these trigger points are important to address in patients with chronic pain conditions.13,24-29 Dry needling (DN) is a common technique used to treat MTrPs. This technique is performed by inserting a small monofilament needle into an active or latent trigger point in an effort to elicit a local twitch response and eliminate the MTrP. DN to active trigger points has been shown to decrease Substance P and CGRP, as well as to reduce endplate noise when a local twitch response is elicited.13,30,31 DN can reduce pain, normalize the chemical environment of a MTrP, and restore range of motion and muscle activation patterns.13,32-36 DN of latent trigger points has been shown to elicit a short term segmental antinociceptive effect and normalize muscle activation patterns in the rotator cuff muscles.34,36 Research literature on the impact of DN in a variety of musculoskeletal conditions is expanding in both quality and quantity. In a Cochrane review on acupuncture and DN for low back pain, the authors concluded that DN (when used cautiously) is a useful adjunct to other therapies for chronic LBP.37 In a recent meta-analysis, Kietrys et al38 recommended the use of DN over sham or placebo treatments for upper quarter conditions with MTrPs in order to reduce pain immediately and at 4 weeks.

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A moderate number of randomized controlled trials (RCT) have been performed looking at the effects of DN in a variety of populations and conditions.

Mayoral et al39 showed that DN of active MTrPs preoperatively in subjects awaiting a total knee arthroplasty (TKA) demonstrated less pain and analgesic use at one month as compared to a sham group.

Tekin et al7 examined subjects with MPS in the cervical, thoracic, and scapula musculature through a RCT and found that their Visual Analog Scale (VAS) scores were decreased and quality of life scores were improved following the use of DN. Casaneuva et al40 showed decreased VAS scores immediately and at 6 weeks using DN in a population with fibromyalgia. The authors also saw improvements in the VAS fatigue scale, short form SF-36, and pressure pain threshold.40 Pain-pressure sensitivity was reduced in a RCT performed by Mejuto-Vasquez et al41 looking at DN in subjects with acute mechanical neck pain. Subjects receiving DN showed decreased pain 10 minutes and one week after treatment, as well as significant range of motion increases and wide spread decreases in pressure pain sensitivity.41 Other lower levels of evidence have been published in the form of case studies documenting the use of DN in subjects with low back pain, posterior hip pain, posterior knee pain, and shoulder adhesive capsulitis.42-44 Rainey42 showed that DN with intramuscular electrical stimulation (IES) decreased pain and increased ROM and function within two treatment sessions in a subject with chronic low back and posterior hip pain. No literature was found examining the use of DN in a population with TSP. The purpose of this case series was to document the use of DN with IES in the thoracic spine and the immediate outcomes. Due to the high pace tempo and demands of the subjects’ operational training schedule, the ability to perform multiple treatment sessions and long term follow up was a challenge.

Therefore, this case series examined the subjects’ immediate outcomes after only two DN sessions.

The subjects featured in this case series gave informed consent to participate in the study and were informed that the data of the case reports would be submitted for publication. This case series was not required to be reviewed or approved by a US Navy Institutional Review Board.

CASE DESCRIPTION The first subject in this case series was a 31-year-old active duty military male who self-referred to physical therapy for TSP that had persisted for 8 weeks. He reported a “spasm type” pain with thoracic flexion and bilateral rotation in each respected movement plane. The subject did not report a known cause of initial pain onset and reported pain was not getting better or worse at the time of initial evaluation.

No radiographs were ordered, due to the sub-acute nature of his symptoms and absence of trauma.

Pain was made worse with forward bending, rotating, and activities that loaded the thoracic spine, such as lifting his child and wearing military body armor. No pain was reported with taking a deep breath, decreasing the likelihood of a rib dysfunction being present.

Reduced pain was accomplished for a few minutes after self-soft tissue mobilization to the thoracic paraspinal musculature utilizing a lacrosse ball. He was cleared for red flags and denied any risk factors for cancer, including weight loss, night pain, fatigue, or a previous history of cancer. No neurological symptoms were reported or found and the subject was overall in good health. Subject’s goals were to eliminate pain with weightlifting and forward bending and to be able to return to pain free military training.

He was scheduled to leave for further military training the day after evaluation, so accurate assessment and effective treatment was important.

The second subject was a 27-year-old active duty military male with complaints of TSP since 2006, which started with a weight-lifting injury when he felt a back spasm during deadlifting. He had previous thoracic spine radiographs ordered and evaluated by his primary care physician, due to the chronicity of his symptoms. These radiographs were negative for bony abnormality. Pain was elicited following heavy weight-lifting workouts the day following his lifting activities. He reported a sensation of stiffness and occasional pain with a deep breath.

Pain was relieved with a few days of rest, but always returned following a lifting workout. He was cleared for red flags, had no signs or symptoms of neurologic involvement, and was overall in good health.

Subject’s goals were to be able to return to pain free weight-lifting without the need for multiple rest days following a workout.

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Outcome tools utilized in this case series included the Visual Analog Scale (VAS), Numeric pain rating scale (NPRS), and the Global Rating of Change scale (GROC). The VAS was used to evaluate the subjects’ primary complaint via pain rating upon initial evaluation and post treatment. Upon initial evaluation, Subject 1 marked his VAS pain level at 61 mm during standing forward flexion. Subject 2 marked his pain at 43mm, but reported as high as 68mm in the last two weeks. The VAS has been found to be a reliable measure of pain with an ICC of .97 (95% CI .96-.98).45 This tool consists of a 100mm line with two descriptors to describe pain levels. The far left indicates no pain, with the far right edge indicating extreme pain.46 Jensen et al46 investigated how to interpret VAS scores and levels of change. Groups were found based on levels of pain as follows: No pain 0 to 1.4mm, mild pain 27 to 28mm, moderate pain 56 to 58mm and severe pain 83 to 87mm. These groupings align well with the groups described by Kelly47, which indicate “mild pain” as less than 30mm, “moderate pain” as 31 to 69 and “severe pain” as greater than 70mm. Both subjects fell into the “moderate pain” group upon initial evaluation. Change scores of 13.3 on the VAS indicate “a little pain relief”, 20mm changes indicate “some relief”, 43.7mm indicate “a lot of relief” and finally 61.6mm changes indicate “complete relief”.46 During objective movement testing, a quick verbal NPRS ranging from 0 (no pain) to10 (worst pain imaginable) was used. The NPRS has been shown to be reliable and valid with a clinically meaningful change of 2 points.48,49 The GROC was completed by both subjects following treatment. The GROC consists of a 15 point scale ranging from -7 (a very great deal worse) to 0 (about the same) to +7 (a very great deal better). The minimally clinically important difference (MCID) has been reported to be +3 with +3 to +4 indicating small changes, +4 to +5 indicating moderate changes and +6 to +7 indicating large changes.50 The construct validity of the GROC has been shown with a Pearson correlation between the Modified Oswestry and the GROC of .78.51 A Modified Oswestry was not utilized in this case series, because its questions were designed for lower level activities of daily living (ADLs). The subjects in this case series were high level military operators, their level of function would

result in not reaching the MCID on a tool such as the Modified Oswestry throughout the treatment period and likely cause a “floor effect”.

Initial Clinical Impression For Subject 1, the subjective evaluation indicated a differential diagnosis to include joint impairments in the thoracic facet joints and or costovertebral joints, muscle strain, MPS, and motor control dysfunction.

With no red flags, neurologic signs, or mechanism of injury, imaging was not considered necessary. The subjective evaluation of Subject 2 led to the same differential diagnosis as Subject 1.

EVALUATION Specific movement pattern “bench marks” were utilized to deem a movement pattern within functional limits (WFL). These bench marks were taken from the Selective Functional Movement Assessment (SFMA), which is a comprehensive movement based assessment system used to classify fundamental movement patterns, identify musculoskeletal dysfunction and direct manual therapy and therapeutic exercise interventions.52 Standing forward bending (multi-segmental flexion; Figures 1A-B) was WFL if the subject was able to achieve a posterior weight shift of the hips and pelvis relative to the base of support and touch their toes without bending the knees, while maintaining a uniform spinal curve and a sacral angle of >70 degrees. The sacral angle (Figure 1C) is measured by assessing the angle of the sacrum relative to the vertical axis as the subject bends forward. In functional forward bending patterns, as a subject flexes forward, an appreciable amount (>70 degrees) of sacral anterior tilt occurs.

Multi-segmental flexion has an intra-reliability of .46 to .85 across raters of various experience levels.53 Standing backward bending (multi-segmental extension) was WFL if the subject was able to anterior weight shift (ASIS past the toes) and raise and maintain the arms at >170 degree flexion angle, while performing general spinal extension (scapula spines past the heels) and maintaining a uniform spinal curve.

Multi-segmental extension has an intra-reliability of .25 to .87 across raters of various experience levels.53 Standing rotation (multi-segmental rotation; Figure 2A-B) was WFL if the subject was able to rotate the

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Figure 1. A. Multi-Segmental Flexion (start), B. Multi-Segmental Flexion (ďŹ nish), C. Sacral Angle.

Figure 2. A. Multi-Segmental Rotation (start), B. Multi-Segmental Rotation (start).

trunk 50 degrees and pelvis 50 degrees (summative rotation of 100 degrees), while preventing any spinal or pelvic deviation or excessive knee flexion.

In order to look more specifically at thoracic spine mobility versus motor control dysfunction, a lumbar locked position was utilized to examine thoracic rotation ROM. Multi-segmental rotation has an intra-

reliability of .52 to .89 (right) and .52 to .77 (left) across raters of various experience levels.53 Lumbar locked thoracic rotation (Figure 3A-B) has been shown to be reliable with in session inter-rater reliability of .85 to .95 and a Minimally Detectable Change (MDC) of 2.8 to 6.3 degrees.53 The in ses-

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that increased thoracic motion exists when it doesn’t.

While keeping the hips and forearm in position, the subject rotates the thoracic spine to its limit. This kneeling position in hip and lumbar flexion is utilized to minimize hip and lumbar spine motion during thoracic rotation, due to the flexed position in which both are placed. Thoracic rotation ROM can be assessed visually and/or with a bubble inclinometer positioned between the scapular spines at the T1 to T2 level. This motion is performed both actively and passively (with assistance from the administrator).

Lumbar locked thoracic rotation has been reported in the literature53; however, most have utilized the “arm behind the head” position versus the “behind the low back” position. The authors of this case series believe the “arm behind the low back” position is superior secondary to the previously mentioned reasons.

Figure 3. A. Lumbar Locked Thoracic Rotation (start), B. Lumbar Locked Thoracic Rotation (finish).

sion intra-rater reliability is .86 to .95 with an MDC of 2.1 to 5.9 degrees.54 The lumbar locked position consists of the subject being in a kneeling position sitting on their heels with the forearm of one arm resting on the treatment table (elbow flexed at 90 degrees) providing upper extremity support and in line with the midline of the body; the other arm is placed behind the low back. The position of the subject’s arm behind the low back was intended to limit movement of the shoulder girdle and capture isolated thoracic spine rotation, preventing a falsepositive limitation secondary to an anterior shoulder girdle tissue extensibility limitation (e.g. pectoral musculature hypertonicity). This arm position can also help to limit a false negative test by reducing the likelihood of compensation with scapular and/or glenohumeral hypermobility and making it appear

It is the thought process presented by the creators of the SFMA and the authors opinion that testing movement patterns both actively and passively, as well as changing the position of testing (e.g. spinal weight bearing versus non-weight bearing), is important in order to alter motor control demands on the body.52 Throughout this process, the impairments may be distinguished as either a mobility dysfunction (tissue extensibility and/or joint restriction) or motor control dysfunction. It has been theorized by the creators of the SFMA that when a movement elicits the same degree of limitations and/or pain in multiple testing positions (e.g. spinal weight bearing and non-weight bearing) or when both active and passive ROM are limited, a mobility dysfunction is likely present and further biomechanical assessment would be needed to determine structural dysfunction (i.e. tissue extensibility and/or joint restriction).52 A motor control dysfunction is likely present when movement dysfunction and/or pain are not consistent and improve with less challenging postural positions (e.g. spinal non-weight bearing) or when active ROM is limited, but passive ROM is normal.52 Subject 1: Postural examination was assessed visually for structural changes and deformity and revealed increased thoracic kyphosis and bilateral paraspinal hypertonicity in the mid-thoracic spine.

Movement pattern assessment via active range of motion (AROM) testing was performed and assessed visually for both quality and quantity of movement.

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Upon AROM examination, standing forward flexion elicited a VAS pain score of 61mm in the lower thoracic spine, but ROM was WFL. Pain started as his fingers reached mid-thigh, but he was able to reach his toes. Standing spinal extension was WFL with no pain reported. Standing rotation was WFL with reported pain (3/10 on NRPS) at end range bilaterally.

Upon movement testing, Subject 1 had 55 degrees of left rotation in the lumbar locked position with no pain and no change in ROM when passive ROM was applied. There was 45 degrees of right rotation with a 10 degree increase in ROM when passive ROM was applied; slight pain (2/10) was reported with both active and passive ROM to the right. All lumbar locked thoracic rotation movements were objectively assessed using a bubble inclinometer. To further evaluate thoracic spine flexion, a quadruped position was used to reduce the motor control demand of the spine and trunk musculature (non-weight bearing) compared to the previously evaluated standing position.

The subject was asked to arch his back up as high as he could and reported pain (4/10 on NPRS) with ROM WFL. Palpation examination revealed tissue hypertonicity and tenderness along bilateral thoracic paraspinals. Joint accessory examination revealed pain with posterior to anterior (P/A) pressure through the spinous process of T9 to T12 with no hypo- or hypermobility noticed. No painful symptoms were found with costovertebral P/A testing.

Subject 2: Postural examination showed the shoulders were slightly anterior to the ear with no significant changes in thoracic spinal curvature. Standing forward and backward bending, as described above, did not elicit pain and was WFL. Standing rotation elicited a “sense of tightness” with a VAS score of 43mm and was restricted 25% in both directions.

The lumbar locked position was once again utilized to investigate thoracic spine rotation. Forty degrees of rotation was achieved actively in both directions and 50 degrees was achieved with passive overpressure. He also felt a “sense of tightness” with this testing position, but no increase in pain. Palpation examination also revealed tissue hypertonicity and tenderness along bilateral thoracic paraspinals. Joint accessory examination revealed pain (4/10 on NPRS) with P/A testing to the T4 to T7 spinal levels with no

hypo- or hypermobility noticed. No pain was reported with costovertebral P/A testing. He reported his pain intensity ranging from 5 to 7/10 on the NPRS the day following his weightlifting activities.

Second Clinical Impression Subject 1: From the results of examination, this subject demonstrated thoracic spine paraspinal hypertonicity and tenderness in the lower half of the thoracic spine and a spinal flexion motor control dysfunction. The motor control dysfunction was indicated by the reduction in pain when postural demands of the spine and trunk musculature were reduced through positional changes. No joint restrictions were indicated through P/A testing, and demonstrated by his ability to go through full ROM. Subject 2: A motor control dysfunction was also seen in this subject, but in a rotational direction. This was indicated by increased rotation ROM actively versus passively. He also demonstrated thoracic spine paraspinal hypertonicity and tenderness upon paraspinal tissue palpation assessment located in the upper half of the thoracic spine.

INTERVENTION DN with the use of IES was chosen to be used in both subjects as it is an effective way to reduce muscle hypertonicity and MTrPs, allowing the administrator to directly influence the multifidus musculature, which could be difficult with other soft tissue techniques due to the overlying paraspinals. A 60mm length by .30mm diameter monofilament needle was used to treat both the paraspinal and multifidus musculature at the levels of elicited pain with P/A testing. Risks were discussed with the subject to include pneumothorax and infection along with the common side effect of short term muscle soreness. Neither subject had any contraindications for DN, such as a local infection, bleeding disorders, immune suppression, or significant fear of needles.

The DN technique included standard protocol of disinfection of the skin with 70% isopropyl alcohol followed by insertion of the needle within one finger breadth (subjects’ finger) of the spinous process until lamina was contacted by the tip of the needle to ensure that the multifidus was being treated. This needle placement is the standard distance used for

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DN in the multifidus. The purpose of using the finger breadth of the subject is to allow for variance of distance from the spinous process based on the subjectâ&#x20AC;&#x2122;s body size. Both sides of the spinal levels were treated at T9 to T12 for Subject 1 and T4 to T7 for Subject 2 (Figure 4A-B). The needles were left in situ and the IES unit (Figure 5A-B) was attached.

The use of IES was indicated, due to the chronicity of symptoms in both cases and clinician experience using IES in the multifidus to reduce both pain and hypertonicity. The IES unit (Figure 6) utilized was an ES-130 by ITOÂŽ (Japan), which is a three channel unit (6 leads) that produces a pulsed asymmetric biphasic square waveform. The 6 leads had alligator clips attached, which allowed for easy attachment onto the needle shafts. Upon attachment to the nee-

Figure 5. A. Dry Needling set-up with IES (view 1), B. Dry Needling set-up with IES (view 2).

Figure 4. A. Needle Placement, B. Needle Placement (closeup).

dles, the IES unit was set with a frequency level of 4 (1.5Hz) and the intensity increased to subject comfort, which ranged from level 4 to 5/10 and was at an intensity that elicited repeated muscular contraction. A frequency of 1.5Hz allowed for 1 to 2 muscle contractions per second at this setting. The IES unit was allowed to run for 20 minutes in all treatment sessions.

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Figure 6. IES Unit (ES-130 by ITO®).

DISCUSSION Subject 1: Due to the short treatment window for Subject 1, he was only treated once before having to return to operational military training. The spinal levels treated with the DN technique described above were T9 to T12. He was given a Home Exercise Program (HEP) that included supine assisted sit-up exercises (Figure 7A-B). This exercise was selected to address his motor control dysfunction by creating a situation in which his body could go through pain free flexion ROM. Progression was accomplished by reducing assistance as a way to increase motor control demands.

Following DN, one set of 20 supine assisted sit-up exercises was performed. Directly following treatment, the subject was asked to complete the GROC and standing forward bending was re-evaluated. The subject rated himself as a +5 (quite a bit better) on the GROC and pain was reduced on the VAS to 23mm with forward bending with continued ability to touch his toes.

Subject 1 returned for treatment 19 days later following 2 ½ weeks of military training. He reported that the two days following treatment he felt “a little better” and pain was now intermittent instead of constant. The day of his second treatment he rated himself on the GROC as 0 (about the same). Upon evaluation, he had a VAS score of 26mm with forward bending and was able to touch his toes, which was a 35mm change in VAS score from initial evaluation. Standing trunk rotation was WFL and pain free.

This demonstrated elimination of pain felt with rotation on initial evaluation. DN with IES was used in

Figure 7. A. Assisted Sit-ups (start), B. Assisted Sit-ups (finish).

the same fashion as the initial treatment. This was followed by a thoracic stability exercise in a supine position with the hips and knees at 90 degrees. The subject then raised a 5 pound ball overhead while controlling the lumbar and thoracic spine (Figure 8A-B). This exercise was selected to challenge the subjects’ motor control in the thoracic spine with lifting tasks and could be progressed into more challenging positions (e.g. half kneeling positions and standing) as tolerance progressed. Following treatment, he had no pain with forward flexion ROM. Subject 2: For this subject, the DN technique was used at the spinal levels T4 to T7 for two treatment sessions that were 48 hours apart. Both sessions were identical in set up and duration, as described above. A HEP that consisted of side lying thoracic rotation (Figure 9) and supine thoracic rotation with

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a stable scapula (Figure 10A-B) was used to influence thoracic rotation mobility. The subject continued to perform his normal lifting routine that included Olympic lifting, rowing machine, and running. He completed the GROC 24 hours following his second treatment and rated himself as +5 (quite a bit better). Pain following his weightlifting workouts was reported to be minimal (20mm) with only a slight “sense of tightness”. Standing trunk rotation was WFL following the second treatment.

Thoracic spine pain may be a more common issue than previously thought and can have large impacts in activity level and tolerance. The presence of MTrPs have been shown to be prevalent in other spinal conditions, such as WAD, and chronic low back pain,11,12 and could be a contributing factor in thoracic spine

Figure 8. A. Supine 90/90 overhead lift (start), B. Supine 90/90 overhead lift (finish).

Figure 9. Side lying rotation.

Figure 10. A. Supine rotation with stable scapula (start), B. Supine rotation w/ stable scapula (finish).

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Table 1. Outcome Measures.

Subject 1

Initial Exam Final Exam 61mm 26mm - -+5 Subject 2 Initial Exam Final Exam VAS 43mm 20mm GROC - -+5 VAS = Visual Analog Scale; GROC = Global Rating of Change VAS GROC

Table 2. Objective Findings.

Subject 1 Initial Exam S t a n d i n g F l ex i o n WFL Standing Extension WFL S t a n d i ng R o t a t i o n WFL Lumbar locked Rotation Left 55°, Right 45° Subject 2 Initial Exam Standing Flexion WFL Standing Rotation 25% limited bilateral, SOT Lumbar locked Rotation Left 40°, Right 40°, SOT SOT = Sense of Tightness

Final Exam WFL WFL WFL Left 55°, Right 55° Final Exam WFL WFL Left 50°, Right 50°

pain. MTrPs may be caused by sustained postures and repetitive tasks which would occur often in the thoracic spine. For example, individuals who work in an office setting will often have sustained sitting postures for hours throughout the day. Specifically, the subjects in this case series must carry their military gear for long periods which places the thoracic spine in a flexed position for sustained periods of time.

DN has been shown to be an efficient treatment for MTrPs and was chosen as an appropriate treatment in both subject cases, due to the previously published works on DN and the authors’ personal experience.

The authors of this case series have seen a trend towards motor control dysfunctions in the thoracic spine in subjects with TSP, shoulder and neck pain.

DN is commonly used to treat the deep multifidus musculature with the theory that MTrPs could influence timing and sequencing of the multifidus firing during activity, thus establishing a motor control dysfunction.

In both of the presented cases, subject perceived symptoms were unchanging and had been both subacute and chronic in nature (8 weeks and 8 years respectively). Motor control dysfunctions were indicated in both subjects due to changing symptoms with different postural positions and no signs of joint restrictions. Upon initiating treatment consisting of DN with IES and motor control exercises, symptoms were quickly and significantly reduced. Subject 1 had a decrease from a 61mm VAS score on initial evalua-

tion to a 23mm score on follow up treatment 19 days later. Following his second treatment, he had a 0mm VAS score (no pain) with forward bending. While he rated himself as “about the same” on the GROC, his VAS scores from visit one to two indicated a moderate change.46 Subject 2 indicated feeling “quite a bit better” on the GROC following his second visit, which matched his VAS score change from 43mm to 20mm following his second treatment. This 23mm change indicated “some relief”.46 Limitations to this case series were greatly influenced by the nature of this particular military clinic.

Due to the high tempo of operational military training and drop in nature of the subjects, a consistent treatment plan was not able to be implemented. Longer term follow up was also made difficult, due to training and travel demands and requirements of the subjects, leaving long term outcomes undetermined.

Increasing use of DN illuminates the need for further research in the form of RCTs in order to investigate the influence of DN with and without IES for treatment of the multifidus musculature in subjects with non-specific cervical, thoracic, and lumbar pain.

CONCLUSION Thoracic spine pain can be a common occurrence with many possible causes, including MTrPs. This case series demonstrated positive, short-term effects of treating MTrPs present in the thoracic spine with DN and IES in two subjects with nonspecific, thoracic spine pain. The quick and measureable changes in pain and movement seen in these two subjects demonstrate the positive effects of DN on subjects with different chronicity of symptoms. Further research is indicated, to examine treatment of MTrPs in the thoracic spine using DN with and without IES. REFERENCES 1. Manchikanti L, Singh V, Pampati V, Beyer CD. Evaluation of prevalence of facet joint pain in chronic thoracic pain. BMC Musculoskelet Disord.

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29. Curatolo M, Arendt-Nielsen L, Petersen-Felix S. Central hypersensitivity in chronic pain: mechanisms and clinical implications. Phys Med Rehabil Clin N Am. 2006;17:287–302.

30. Chen JT, Chung KC, Hou CR, Kuan CR, Chen SM, Hong CZ. Inhibatory effect of dry needling on the spontaneous electrical activity recorded from

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myofascial trigger spots of rabbit skeletal muscle.

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33. Fernandez-Carnero J, La Touche R, Ortega-Santiago R, Galan-del-Rio F, Pesquera J, Ge HY, et al. Shortterm effects of dry needling of active myofascial trigger points in the masseter muscle in patients with temporomandibular disorders. J Orofac Pain.

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34. Lucas KR, Polus BI, Rich PS. Latent myofascial trigger points: their effects on muscle activation and movement efficiency. J Bodyw Mov Ther. 2004;8:160– 166.

35. Lucas KR, Rich PA, Polus BI. Muscle activation patterns in the scapular positioning muscles during loaded scapular plane elevation: the effects of latent myofascial trigger points. Clin Biomech. 2010;25:765– 70.

36. Srbely JZ, Dickey JP, Lee D, Lowerison M. Dry needle stimulation of myofascial trigger points evokes segmental antinociceptive effects. J Rehabil Med. 2010;42:463–468.

37. Furlan A, van Tulder M, Cherkin D, Tsukayama H, Lao L, Koes B, Berman B: Acupuncture and dry needling for low back pain: an updated systematic review within the framework of the Cochrane Collaboration. Spine. 2005;30(8):944-963.

38. Kietrys DM, Palombaro KM, Azzaretto E, Hubler R, Schaller B, Schlussel JM, Tucker M. Effectivness of dry needling for upper-quarter myofascial pain: a systematic review and meta-analysis. J Orthop Sports Phys ther. 2013;43(9):620-634.

39. Mayoral O, Salvat I, Martin MT, Martin S, Santiago J, Cotarelo J, Rodriguez C. Efficacy of myofascial trigger point dry needling in the prevention of pain after total knee arthroplasty: a randomized, double blinded placebo controlled trial. Evid Based Complement Alternat Med. Volume 2013, Article ID 694941, 8 pages.

40. Casaneuva B, Rivas P, Rodero B, Quintial C, Llorea J, Gonzalez-Gay MA. Short term improvement following dry needle stimulation of tender points in fibromyalgia. Rheumatol Int. 2013; April 23.

41. Mejuto-Vasquez MJ, Salmon-Moreno J, OrtegaSantiago R. Short-term changes in neck pain wide spread pressure pain sensitivity and cervical range

of motion after the application of triggerpoint dry needling in pts with acute mechanical neck pain: a randomized clinical trial. J Orthop Sports Phys Ther.

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42. Rainey CE. The use of trigger point dry needling and intramuscular electrical stimulation for a subject with chronic low back pain: a case report. Int J Sports Phys Ther. 2013;8(2):145-161.

43. Mason JS, Tansey KA, Westick RB. Treatment of subacute posterior knee pain in an adolescent ballet dancer utilizing trigger point dry needling: a case report. Int J Sports Phys Ther. 2014;9(1):116-124.

44. Clewley D, Flynn T, Koppenhaur S. Trigger point dry needling as an adjunct treatment for a patient with adhesive capsulitis of the shoulder. J Orthop Sports Phys Ther. 2014;44(2):92-101.

45. Bijur PE, Silver W, Gallagher J. Reliability of the visual analog scale for measurements of acute pain.

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47. Kelly AM. The minimum clinically significant difference in visual analogue scale pain score does not differ with severity of pain. Emerg Med. 2001;18:205-207.

48. Childs JD, Piva SR, Fritz JM. Responsiveness of the numeric pain rating scale in patients with low back pain. Spine. 2005;30:1331-1334.

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IJSPT

CLINICAL COMMENTARY

RETURN TO SWIMMING PROTOCOL FOR COMPETITIVE SWIMMERS: A POST-OPERATIVE CASE STUDY AND FUNDAMENTALS Tracy Spigelman, PhD, ATC1 Aaron Sciascia, MS, ATC, NASM-PES2 Tim Uhl, PhD, ATC, PT3

ABSTRACT A large percentage of swimmers report shoulder pain during their swimming career. Shoulder pain in swimmers has been attributed to duration of swim practice, total yardage, and break down in stroke technique. Rehabilitation programs are generally land-based and cannot adequately address the intricacies of the swimming strokes. Return to swimming protocols (RTSP) that address progression of yardage are scarce, yet needed. The purpose of this clinical commentary is to familiarize the clinician with the culture and vernacular of swimming, and to provide a suggested yardage based RTSP for high school and collegiate level swimmers.

Keywords: Freestyle stroke, technique, yardage Level of Evidence: 5

1

Eastern Kentucky University, Richmond, KY, USA The Shoulder Center of Kentucky, Lexington Clinic, Lexington, KY, USA 3 University of Kentucky, Lexington, KY, USA 2

CORRESPONDING AUTHOR Tracy Spigelman, Ph.D., ATC Clinical Coordinator/Assistant Professor Athletic Training Education Program Eastern Kentucky University Richmond, KY 40475 USA E-mail: Tracy.spigelman@eku.edu

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INTRODUCTION Forty to ninety-one percent of age group through mastersâ&#x20AC;&#x2122; level swimmers report shoulder pain at some point during their careers.1-6 Furthermore, increased shoulder pain has been related to duration of swim practice, total yardage, and break down in stroke technique.1,3,7-9 During rehabilitation, all of these components may need to be addressed. One key component of rehabilitation is return to sport specific activities and progressions. Interval return to sport programs exist for activities such as baseball,10,11 running, tennis, golf and softball.12-14 Unfortunately, interval return to swimming protocols (RTSP) are scarce.15 The culture of swimming is that the athletes spend large quantities of time in the pool practicing; therefore it is important to get swimmers back in the pool practicing as soon as possible.16 Adding to the complexity of utilizing an RTSP, swimming has its own vocabulary and training rituals that are engrained in the culture. One beneficial component of the swimming culture is that training is yardage based allowing for the development of an interval training protocol utilizing yardage. Another key component in the swimming culture focused on by coaches and swimmers is the importance of proper stroke mechanics to increase efficiency and decrease injury risk. Poor mechanics during swimming has been linked with injuries and consequently needs to be understood and addressed in the rehabilitation process.5,17-19 This current concept paper has three objectives.

First, to familiarize the clinician with the culture and vocabulary of swimming so that communication between the clinician and athlete and coaches is enhanced. Second, to describe a protocol based on yardage that incorporates specific drills to improve stroke mechanics and interval work in order to gradually restore speed. The final objective is to share a case example of how the RTSP was used in the return to sport of a collegiate swimmer.

Swimming Rehabilitation Review Swimming specific rehabilitation traditionally focuses on scapular stabilization,20 core body strength, neuromuscular re-education of the shoulder musculature,21,22 correction of forward head and rounded shoulder posture,23 and generally takes place in a clinic on dry land. There are excellent

articles and case reports that address clinical rehabilitation techniques but these are not the focus of this clinical commentary.20,23-26 Attempts to replicate freestyle stroke technique using dry-land swimming benches have been found to recruit muscle in different patterns and may not replicate the swimming stroke ideally.16,27 So, when working to correct a swimmerâ&#x20AC;&#x2122;s stroke technique, it is best done in the water. Understanding the stroke mechanics and the drills that are commonly used by coaches in the swimming community to enhance stroke technique is important.

Freestyle Biomechanics Proper technique of the freestyle stroke is important to injury prevention.4,5,9,17,18,28,29 While the swim coach should be the primary person to evaluate a swimmerâ&#x20AC;&#x2122;s stroke technique, clinicians should have working knowledge of how freestyle stroke technique should look (Figure 1). There are several extensive articles that describe the mechanics of freestyle and the other competitive swimming strokes that are beyond the scope of this clinical commentary. For more in-depth knowledge the reader is referred to these articles.4,8,17,18,28-30 There are various descriptions of the freestyle stroke.

The biomechanical literature breaks freestyle stroke into five phases,31 while the more clinically focused literature breaks the freestyle stroke into three or four phases.4,29,32 Since the objective of this paper is to provide a general RTSP for clinicians, the freestyle stroke has been divided into four phases: hand entry, early pull-through, late pull-through, and

Figure 1. The freestyle swimming stroke.

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Figure 2. Hand entry (right UE)

Figure 4. Late pull-through phase (right UE)

Figure 3. Early pull-through phase (right UE)

Figure 5. Recovery phase of the freestyle stroke. Note high elbow position.

recovery.4,18,28,30 It is important to note that a breakdown in one part of the stroke cycle can result in compensatory strategies throughout the rest of the cycle, leading to potential injury.4,9,18,29,30 Hand entry occurs as the finger tips break the surface of the water (Figure 2).4,18 Early pull-through is defined as the point from which the hand enters the water till it is perpendicular with the body (Figure 3).4,30 During the late pull-through phase, the arm moves under the body accelerating until the arm exits the water (Figure 4).4 Recovery phase begins as the arm exits the water and ends as the finger tips break the surface of the water (Figure 5).4,8,18,28,29

eral to the midline. A right hand should enter the water at approximately one o’clock and a left hand at 11 o’clock with the swimmer’s head representing 12 o’clock. Deviations, either medial or lateral represent an error because they increase the stress on the rotator cuff.4,8,17,18,28,29 During early pull-through, a common flaw observed in swimming mechanics is the “dropped elbow”.4,18,28,29 As the hand enters the water, the wrist is slightly flexed and the elbow should remain higher than the hand while the arm pulls under the body. This position engages the latissumus dorsi muscles and sets the swimmer up to pull the body over the arm preventing impingement.4,18,29 It also creates a smooth, symmetrical body roll which decreases stress on the rotator cuff muscles and allows the scapula to stay appropriately anchored on the thorax.4,17,18 A straight arm recovery is yet another flaw that occurs during freestyle swim-

Each phase has the potential to have biomechanical flaws that could result in injury.4,5,29 A common flaw observed during hand entry is when the swimmer enters the water with the hand either medial or lat-

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Table 1. Swimming Tools. Tools commonly used by competitive swimmers. Tools should be used with caution depending on swimmerâ&#x20AC;&#x2122;s injury.

Tool

Name Kickboard

Use/Indications Used to focus on kicking only; Most commonly used with arms extended in front of the body; creates lumbar lordosis

Contraindications Shoulder injuries; spondylolysis

Pull buoy

Used to focus on arm stroke only; Placed between upper legs to prevent kicking while providing buoyancy to the lower body

Shoulder tendinitis/tendinosis; elbow or forearm pain

Fins

Used to increase leg length and surface area of the feet; increase propulsion of stroke

Acute ankle injuries; knee pain

Zoomers

Used to increase leg strength; increase surface area of the feet, but are shorter than fins and allow for rapid leg motions to increase forward propulsion Worn on hands; come in variety of sizes; increase surface area of the hand; slow down pull when worn, but build strength while pulling

Acute ankle injuries; knee pain

Paddles

ming.4,29 This means that during the recovery phase, the elbow is fully extended while the arm is out of the water. During the recovery phase, a bent elbow is favorable because it reduces the amount of stress on the rotator cuff.29 For a more in depth explanation of errors made during freestyle swimming, readers are encouraged to review the article by Virag et al.29 Freestyle swimming uses a flutter kick. Flutter kicking requires alternating motions of the legs. When performed correctly, the flutter kick agitates the water giving it the appearance of boiling water. The power of the kick comes from the hip flexors and extensors.

The knee is slightly flexed and extended while the ankles are plantar flexed and inverted. The even four or six beat kick (the equivalent of two or three kicks per individual arm revolution) are most commonly used by distance and sprinters, respectively. , Taking a breath every three arm strokes, also referred to as an alternate breathing pattern, is also helpful for developing a freestyle stroke with correct biomechanics.18,28 Return to Swimming Protocol To familiarize the clinician with the swimming culture, a vocabulary of common terminology has been

Shoulder injury or pain; improper stroke technique

created (Appendix 1) to better communicate with the swimmer and speak their language when discussing swimming. There are several pieces of equipment, described in Table 1, that are commonly used in swim training and may be beneficial in returning a swimmer to full activity. However, there are contraindications to the use of equipment that are important for the rehabilitation professional to understand. Numerous drills are used to help swimmers focus on maintaining proper stroke technique throughout swim practice. The most common drills and the phase of the stroke cycle they focus on are described in Table 2.

The criterion to begin the RTSP include: 1) the swimmer should be nearly pain free in the shoulder complex and 2) full active extension and external rotation of the glenohumeral joint should exist. The strength of the rotator cuff and scapular stabilizing muscles should be a 5/5 when tested using traditional manual muscle testing.25,33 Phase One of the RTSP focuses on stroke technique drills to prevent the swimmer from reverting to bad habits that could reinjure the shoulder. The yardage increases in small increments to prevent overuse. Phase Two focuses on interval

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Table 2. Swimming Drills. Drills used by swimmers to focus on technique during various phases of the stroke cycle.

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work designed to help build the swimmer’s muscular and cardiovascular fitness levels. Yardage increases in larger increments in order to help build endurance as the swimmer demonstrates he or she can tolerate longer practices. The RTSP is designed to gradually return the swimmer to practice, so focus on the swimmer’s specialty stroke or distance is not

addressed at this point. It is the authors’ opinion that the swimmer should swim with proper freestyle technique and without pain before performing event specific and distance specific practices.

Table 3 illustrates the key points of progression during the RTSP. The components of a swim practice

Table 3. Key Points of the Return to Swimming Protocol (RTSP). Overview of the RTSP including the major components of a swimming workout and criteria for progression.

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Table 4. Swimming Soreness Rules (adapted with permission from Axe, M). Guidelines to help the swimmer recognize pain and the clinician adjust the swimming portion of shoulder rehabilitation.

include variations in warm-up, drills, kick, pull, intensity, and rest. Criteria to progress from phase to phase are defined in Table 3. It is necessary for the swimmer and coach to understand that the athlete should progress slowly. Increases in pain, soreness, or discomfort need to be recognized by the swimmer as possible warning signs to decrease training and have the coach re-evaluate stroke mechanics (Table 4). The proposed RTSP protocol has been previously used in a collegiate swimmer to assist with return to swimming.

Case Example A 20-year-old, male, National Collegiate Athletic Association (NCAA) Division III, distance swimmer reported to the Athletic Training Clinic following a closed anterior, Bankart repair on his right shoulder.

He had completed rehabilitation at home during the summer months and was released by his physician for return to swimming upon return to college. He reported to school and was examined, demonstrating full range of motion, normal strength, and a negative anterior apprehension test.

The swimmer worked with the both the Certified Athletic Trainer and his coach using the outlined RTSP. He reported to the pool Monday, Wednesday and Friday and to the Athletic Training Clinic for formal rehabilitation Tuesday and Thursday. Table 5 details the swimmer’s weekly progression using the RTSP. Phase One/Week One emphasized improving stroke technique with increased recovery. A “stroke progression,” series of drills to focus on stroke technique, was designed by the coach and incorporated into each warm up (Table 6). The swimmer increased

his yardage by 30% between days 1 and 2, and 20% between days 2 and 3. This might have been too large a jump in yardage as pain was reported in the beginning of the second week that resulted in a few days off. During weeks two and three, the swimmer’s daily yardage was increased by less than 5% increments, focus was placed on drill work and kicking, and interval work was introduced. No complaints or increase in symptoms were reported.

As the swimmer entered Phase Two, his practices consisted mostly of interval work. Yardage was slightly decreased (from 3750 yds to 2800 yds) to accommodate for the increase in intensity during week four. Entering week five, interval work became the primary focus, with drill work at the end of practice to remind the swimmer to focus on technique even when he was fatigued, as suggested within the RTSP. The swimmer was able to tolerate the progression well with his surgical shoulder, but complained of pain in his left shoulder in week six. Yardage was decreased and drill work became the main focus of the practices because this was the only way the swimmer could maintain “perfect stroke technique.”

Reports from the coach noted the swimmer could tolerate practice as long as he used “perfect stroke technique.” Practices were adapted to be mostly drill work, but ultimately, the swimmer returned to the doctor for the pain and was diagnosed with a labral tear in the non-involved left shoulder. At that time, his season ended. Feedback from the Certified Athletic Trainer and coach using the RTSP were positive. The coach reported the RTSP was easy to follow and the swimmer progressed well, aside from complications with the opposite shoulder.

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Table 5. Sample Case. Example of a Division III Swimmer applying the RTSP. Major components of a swimming workout are deďŹ ned next to each work out. Intensity is deďŹ ned as a percentage of maximum effort. Rest intervals were adapted based on intensity.

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Table 5. Sample Case. Example of a Division III Swimmer applying the RTSP. Major components of a swimming workout are deďŹ ned next to each work out. Intensity is deďŹ ned as a percentage of maximum effort. Rest intervals were adapted based on intensity. (continued)

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Table 5. Sample Case. Example of a Division III Swimmer applying the RTSP. Major components of a swimming workout are deďŹ ned next to each work out. Intensity is deďŹ ned as a percentage of maximum effort. Rest intervals were adapted based on intensity. (continued)

SUMMARY The RTSP was designed by the lead author who is a Certified Athletic Trainer, former NCAA Division I swimmer, and earned a PhD with an emphasis in biomechanics. The RTSP was inspired by conversa-

tions and interactions with colleagues working with injured swimmers. To date, it has been used by one NCAA Division III collegiate swimmer who was recovering from a closed, anterior Bankart repair, and has been shared among colleagues to use as pro-

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Table 6. Stroke Progression. Series of drills to focus on freestyle stroke technique used during warm-up by Division III swimmer case example.

posed guidelines for a return to sport progression.

While the evidence is limited regarding yardage based protocols for swimmers, the authors believe this program provides clinicians and coaches with a specific starting point to ease a swimmer back into practice. It does not address a swimmer’s specialty (i.e. sprint or distance) because the first goal is to reestablish correct freestyle stroke technique, then increase endurance and training volume. The authors suggest that practices be tailored to a swimmer’s specialty event or stroke once the swimmer has rejoined the team, and can practice pain free.

Feedback from colleagues who have used the RTSP has been positive, but further research is needed in this area to support and refine the RTSP. REFERENCES 1. Sein ML, Walton J, Linklater J, et al. Shoulder pain in elite swimmers: primarily due to swim-volumeinduced supraspinatus tendinopathy. Br. J. Sports Med. 2010;44(2):105-113.

2. Bak K, Fauno P. Clinical findings in competitive swimmers with shoulder pain. Am. J. Sports Med. 1997;25(2):254-260.

3. Brushoj C, Bak K, Johannsen HV, Fauno P. Swimmers’ painful shoulder arthroscopic findings and return rate to sports. Scand. J. Med. Sci. Sports.

2007;17(4):373-377.

4. Wanivenhaus F, Fox AJ, Chaudhury S, Rodeo SA. Epidemiology of injuries and prevention strategies

in competitive swimmers. Sports health.

2012;4(3):246-251.

5. Wolf BR, Ebinger AE, Lawler MP, Britton CL. Injury Patterns in Division I Collegiate Swimming. Am. J. Sports Med. 2009;37(10):2037-2042.

6. Tate A, Turner GN, Knab SE, Jorgensen C, Strittmatter A, Michener LA. Risk Factors Associated With Shoulder Pain and Disability Across the Lifespan of Competitive Swimmers. J Athl Train.

2012;47(2):149-158.

7. Beach ML, Whitney SL, Dickoff-Hoffman SA. Relationship of shoulder flexibility, strength, and endurance to shoulder pain in competitive swimmers. J. Orthop. Sports Phys. Ther.

1992;16(6):262-268.

8. Abrams GD, Safran MR. Diagnosis and management of superior labrum anterior posterior lesions in overhead athletes. Br. J. Sports Med. 2010;44(5): 311-318.

9. Pink MM, Tibone JE. The painful shoulder in the swimming athlete. Orthop. Clin. North Am. 2000;31(2):247-+.

10. Axe M, Hurd W, Snyder-Mackler L. Data-Based Interval Throwing Programs for Baseball Players.

Sports Health: A Multidisciplinary Approach. 2009: 145-153.

11. Escamilla RF, Ionno M, deMahy MS, et al.

Comparison of three baseball-specific 6-week training programs on throwing velocity in high school baseball players. J. Strength Cond. Res. 2012;26(7):1767-1781.

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12. Fredericson M, Cookingham CL, Chaudhari AM, Dowdell BC, Oestreicher N, Sahrmann SA. Hip abductor weakness in distance runners with iliotibial band syndrome. Clin. J. Sport Med. 2000;10(3): 169-175.

13. Kaeding CC, Yu JR, Wright R, Amendola A, Spindler KP. Management and return to play of stress fractures. Clin. J. Sport Med. 2005;15(6):442-447.

14. Reinold MM, Wilk KE, Reed J, Crenshaw K, Andrews JR. Interval sport programs: Guidelines for baseball, tennis, and golf. J. Orthop. Sports Phys. Ther.

2002;32(6):293-298.

15. Hamman S. Considerations and return to swim protocol for the pediatric swimmer after nonoperative injury. Int. J. Sports Phys. Ther.

2014;9(3):388-395.

16. Olbrecht J, Clarys JP. EMG of specific strength training exercises for the front crawl. In: Hollander AP, ed. Biomechanics and medicine in swimming: proceedings of the Fourth International Symposium of Biomechancis in Swimming and Fifth International Congress on Swimming Medicine. United States: Human Kinetics; 1983:136-141.

17. Johnson JN, Gauvin J, Fredericson M. Swimming biomechanics and injury prevention: new stroke techniques and medical considerations. Physician Sportsmed. 2003;31(1):41-46.

18. Lintner D, Noonan TJ, Kibler WB. Injury Patterns and Biomechanics of the Athlete’s Shoulder. Clin.

Sports Med. 2008;27(4):527-551.

19. Pink M, Perry J, Browne A, Scovazzo ML, Kerrigan J. The normal shoulder during freestyle swimming an electromyographic and cinematographic analysis of 12 muscles. Am. J. Sports Med. 1991;19(6):569-576.

20. Ben Kibler W, Sciascia A. Rehabilitation of the Athlete’s Shoulder. Clin. Sports Med. 2008;27(4): 821-+.

21. Swanik KA, Lephart SM, Swanik B, Lephart SP, Stone DA, Fu FH. The effects of shoulder plyometric training on proprioception and selected muscle performance characteristics. J. Shoulder Elbow Surg.

2002;11(6):579-586.

22. Swanik KA, Swanik CB, Lephart SM, Huxel K. The effect of functional training on the incidence of shoulder pain and strength in intercollegiate swimmers. J. Sport Rehabil. 2002;11(2):140-154.

23. Kluemper M, Uhl T, Hazelrigg H. Effect of stretching and strengthening shoulder muscles on forward shoulder posture in competitive swimmers. J. Sport Rehabil. 2006;15(1):58-70.

24. Carson PA. The rehabilitation of a competitive swimmer with an asymmetrical breaststroke movement pattern. Man. Ther. 1999;4(2):100-106.

25. Kurtz JT. A Chiropractic Case Report in the Treatment and Rehabilitation of Swimmer’s Shoulder. J Chiropr. 2004;41(10):32-38.

26. Lynch SS, Thigpen CA, Mihalik JP, Prentice WE, Padua D. The effects of an exercise intervention on forward head and rounded shoulder postures in elite swimmers. Br. J. Sports Med. 2010;44(5):376-381.

27. Clarys JP. Hydrodynamics and electromyography: ergonomics aspects in aquatics. Appl. Ergon.

1985;16(1):11-24.

28. Heinlein SA, Cosgarea AJ. Biomechanical Considerations in the Competitive Swimmer’s Shoulder. Sports Health: A Multidisciplinary Approach.

2010;2(6):519-525.

29. Virag B, Hibberd EE, Oyama S, Padua DA, Myers JB. Prevalence of freestyle biomechanical errors in elite competitive swimmers. Sports health. 2014;6(3):218224.

30. Richardson AB, Jobe FW, Collins HR. The shoulder in competitive swimming. Am. J. Sports Med. 1980;8(3):159-163.

31. Seifert L, Chollet D, Rouard A. Swimming constraints and arm coordination. Human Movement Science. 2007;26(1):68-86.

32. Richardson AB, Jobe FW, Collins HR. The shoulder in competitve swimming. Am. J. Sports Med. 1980;8(3):159-163.

33. Kendall FP, Kendall FP. Muscles : testing and function with posture and pain. 5th ed. Baltimore, MD: Lippincott Williams & Wilkins; 2005.

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Appendix 1. Commonly used swimming vocabulary with examples of how it is used

Word Base

Drills

Distance Swimmer

Lap

Length

Long course

Intensity

Interval

Definition The pace a swimmer or group of swimmer can swim 100 yards repeatedly and still finish with 510 seconds rest. Allows practices to be more individualized.

Used to help swimmers focus on specific parts of the stroke cycle.

They exaggerate one particular phase of the stroke.

A swimmer who competes in events that are over 500 yards/meters.

2 lengths = 50 yards/meters or 1 lap Standard, short course, competition pools are either 25 yards or 25 meters long.

1 length = 25 yards or meters Length is more commonly used than Lap. Olympic length 50 meter pool

Used to describe the effort a swimmer is putting into each set throughout swim practice. It can be defined specifically using % of effort, but is commonly stated as “hard,” “moderate,” or “easy” on a written workout.

Performing the distances in an allotted amount of time; the swimmer will only get rest if they can complete the distance before the defined interval time expires.

Example/Application 5x100 yards base (1:30) 5x100 yards base +5 (1:35) allows for more rest (easier) 5x100 yards base -5 (1:25) allows for less rest (harder) Finger-tip drag drill requires the swimmer to drag the finger tips on the top of the water during the recovery phase.

This exaggerates the bent elbow to help the swimmer focus on proper recovery technique.

500 yards/meters, 1000 yards/meters, 1650 yards/meters.

If a swimmer is asked to swim a “50” that is 2x25 yards/meters of the pool If a swimmer is asked to swim a “100” it means 4x25 yards/meters or 4 length of the pool continuously.

If a swimmer is asked to swim 100 meters long course, it is 2 lengths of the pool.

5x100 yards 85% max effort Or 5x100 yards hard

5x100 yards freestyle 1:45 This means each 200 yard freestyle trial should be completed faster than 1 minute and 45 seconds for the swimmer to get rest. The faster the swimmer completes each 100 yard freestyle trial, the more rest he/she gets.

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Appendix 1. (Continued) Commonly used swimming vocabulary with examples of how it is used

Kick

Mid-distance swimmer Negative Split

Pull

Rest

Scull

Set

Sprinter Swim Stroke

Yardage

Focus on the kick component of the stroke using a kick board prone, in a streamlined position supine or on the side with one arm extended.

A swimmer who competes in events between 200 yards and 500 yards long.

When the second half of a swimming event is faster than the first half of the swimming event Focus on the arm component of the stroke using a pull buoy.

Often hand paddles are used with the pull buoy during a pull set.

This is not advised for an injured shoulder because the added resistance can exacerbate symptoms.

Time between each swim; Rest time means swimmers will always get a break between each swim.

Moving hands and forearm out and in against the water Refers to repetitions of defined distances and is written on a swimmers workout as ____x____; work-out usually contains two-four different sets.

A swimmer who competes in events 100 yards or less.

Performing one of the four competitive strokes Any of the 3 competitive swimming strokes besides Freestyle: Butterfly (fly), Backstroke ( back), Breaststroke (breast) Total yard or meters accumulated swimming during a set practice time. Verbalized by multiples of 25.

5x100 kick w board Kick using a kickboard

200 yard freestyle, 500 yard freestyle 200 yard freestyle 2:30 1st 100 yards 1:20 2nd 100 yards 1:10 5x100 pull w paddles Swim using a pull buoy and hand paddles

5x100 yards Rest 20 This means rest 20 sec after each 100 yard swim.

Commonly used as a drill to appreciate the feel of the water on the hand and forearm 5x100 yard freestyle Means 4 lengths of freestyle repeated 5 times with either a rest or interval to determine recovery time.

100 yard freestyle, 50 yard freestyle 5x100 free swim Swim freestyle 5x 100 Fly Swim butterfly for all 100s

A coach may increase daily yardage from 3000 yards to 6000 yards over the course of the swi m seaso n.

Italicized notations are what would be recorded in a workout log or record for each swimmer.

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IJSPT

CLINICAL COMMENTARY

BEYOND STATISTICAL SIGNIFICANCE: CLINICAL INTERPRETATION OF REHABILITATION RESEARCH LITERATURE Phil Page, PT, PhD, ATC, CSCS, FACSM1

ABSTRACT Evidence-based practice requires clinicians to stay current with the scientific literature. Unfortunately, rehabilitation professionals are often faced with research literature that is difficult to interpret clinically.

Clinical research data is often analyzed with traditional statistical probability (p-values), which may not give rehabilitation professionals enough information to make clinical decisions. Statistically significant differences or outcomes simply address whether to accept or reject a null or directional hypothesis, without providing information on the magnitude or direction of the difference (treatment effect). To improve the interpretation of clinical significance in the rehabilitation literature, researchers commonly include more clinically-relevant information such as confidence intervals and effect sizes. It is important for clinicians to be able to interpret confidence intervals using effect sizes, minimal clinically important differences, and magnitude-based inferences. The purpose of this commentary is to discuss the different aspects of statistical analysis and determinations of clinical relevance in the literature, including validity, significance, effect, and confidence. Understanding these aspects of research will help practitioners better utilize the evidence to improve their clinical decision-making skills.

Key words: Clinical significance, evidence based practice, statistical significance Level of evidence: 5

1

Louisiana State University, Baton Rouge, Louisiana, USA

CORRESPONDING AUTHOR Phil Page E-mail: ppage1@lsu.edu

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INTRODUCTION Evidence-based practice is supposed to affect clinical decision-making, but interpreting research is often difficult for some clinicians. Clinical interpretation of research on treatment outcomes is important because of its influence on clinical decision-making including patient safety and efficacy. Publication in a peer-reviewed journal does not automatically imply proper study design or statistics were used, or that the author’s interpretation of the data was appropriate. Furthermore, statistically significant differences between data sets (or lack thereof) may not always result in an appropriate change in clinical practice. Clinical research is only of value if it is properly interpreted.

From a clinical perspective, the presence (or absence) of statistically significant differences is of limited value. In fact, a non-significant outcome does not automatically imply the treatment was not clinically effective because small sample sizes and measurement variability can influence statistical results.1 Other factors, such as treatment effect calculations and confidence intervals offer much more information for clinicians to assess regarding the application of research finding, including both the magnitude and direction of a treatment outcome.

The purpose of this clinical commentary is to discuss the different aspects of statistical analysis and determinations of clinical relevance in the literature, including validity, significance, effect, and confidence. Understanding these aspects of research will help practitioners better utilize the evidence to improve their clinical decision-making skills.

VALIDITY Clinicians should be able to critically evaluate research for both internal and external validity in order to determine if a study is clinically applicable. Internal validity reflects the amount of bias within a study that may influence the research results. Proper study design and statistical analysis are important factors for internal validity. For additional information on proper research design, the reader is referred to the article “Research Designs in Sports Physical Therapy”.2 The research question drives the research design and statistical analysis. General clinical research designs include clinical trials, cohort studies, and case reports;

each providing different levels of evidence.3 Systematic reviews and randomized clinical trials (RCT) are the highest level of research design. Cohort studies include pre-post designs, epidemiological, and descriptive research. Case reports are among the lowest level of evidence. (Table 1) A recent systematic review found nearly one half of clinical sports medicine literature is comprised of level 1 and level 2 studies, as compared to just 20% of the literature 15 years ago.4 Clear explanation of the population, recruitment, randomization, and blinding are important considerations when evaluating internal validity to identify potential bias. The PEDro scale (http://www.pedro. org.au/english/downloads/pedro-scale/) for rating clinical trials is a valid tool that can be used to analyze clinical trials for quality5 and bias. Detailed description of the intervention and control groups is crucial for both internal and external validity. External validity is the ability of a study to be generalized and applied in clinical situations. While “clinical research” should include patient populations, healthy populations are sometimes used to answer clinical questions such as electromyographical (EMG) analysis of exercises. Practitioners should be cautious when applying results of studies with healthy cohorts to a patient population. Similarly, it is important to differentiate between studies on ‘elite” athletes and recreational athletes in the exercise literature.6 In addition to considering the applicability of the study population to clinical practice, other factors can affect external validity, including the complexity of the protocol and cost effectiveness of the intervention. A repeatable protocol is important in order to reproduce the results of a study in clinical practice.

If an intervention is not cost-effective, it may not be Table 1. Levels of Evidence, adapted from the Oxford Center for Evidence-based I* II* III* IV* V*

Systematic review of randomized trials Randomized trial or observational study with dramatic effect Non-randomized controlled cohort / follow-up studies Case series, case control studies, or historical control trials Mechanism-based reasoning

*Level may be graded up or down on the basis of study quality, consistency between studies, or effect size OCEBM Levels of Evidence Working Group. "The Oxford 2011 Levels of Evidence". Oxford Centre for Evidence-Based Medicine. http://www.cebm.net/index.aspx?o=5653

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feasible in practice. Studies with the highest level of design and high internal validity may still lack external validity, thereby limiting their clinical use.

STATISTICAL SIGNIFICANCE Traditional research uses statistical hypothesis testing in order to infer something about a population using a representative sample. Statistics are used to answer questions of probability, generally using the scientific method, in order to determine if a hypothesis can be accepted or rejected. Statistical significance only addresses a hypothesis about whether or not differences exist, statistically, between groups. As stated previously, the statistical analysis of a study is driven by the research design, which is determined by the research question.

Statistical significance is based on several assumptions. The sample tested should be representative of the entire clinical population. Inferential statistics assume a normal distribution, represented by a bell-shaped curve (Figure 1). A normal distribution is represented by standard deviation (σ) from the mean (μ) value. One standard deviation (SD) represents 68% of the population (in both directions from the mean) while 95% of the population is represented by +2 SDs. Determination of whether statistically significant differences exist or not is centered on accepting or rejecting a “null” or “alternative” hypothesis. A null hypothesis (represented by H0) assumes no difference between groups (or no effect of treatment).

An alternative hypothesis (represented by H1) is what the researcher expects to find from the study, and can be directional or non-directional. A nondirectional hypothesis, based on rejecting the null

Figure 1. Normal distribution bell-shaped curve with standard deviations (From http://en.wikipedia.org/wiki/File: Standard_deviation_diagram.svg)

hypothesis, provides a reference value for the outcome parameter. A directional hypothesis provides a minimal value for the expected outcome parameter.

For example, a directional hypothesis for an intervention that decreases pain by a minimal clinical value may be represented by H1 > 2.

Statistically significant differences are determined using a certain level of probability (the “p-level”, or α) that the researcher chooses, to ensure that one does not incorrectly reject the null hypothesis due to chance, when the null hypothesis is in fact accepted (Type I error). The generally accepted p-level of α =0.05 suggests there is a 95% probability that the researchers correctly rejects the null hypothesis when there is no difference between groups. Therefore, the p-value is only the chance that the researcher makes the correct “yes” or “no” decision regarding a hypothesis.

Statistically significant differences alone should not be the primary influence for clinical interpretation of a study’s outcome for application to patient care. Statistically significant differences do not provide clinical insight into important variables such as treatment effect size, magnitude of change, or direction of the outcome. In addition, whether results achieve statistically significant differences is influenced by factors such as the number and variability of subjects, as well as the magnitude of effect. Therefore, p-values should be considered along with effect size, sample size, and study design.7 Evidence based practitioners should examine research outcomes for their clinical significance rather than just statistical significance. Several measures can be used to determine clinical relevance, including clinical significance, effect sizes, confidence intervals, and magnitude-based inferences.

CLINICAL SIGNIFICANCE While most research focus on statistical significance, clinicians and clinical researchers should focus on clinically significant changes. A study outcome can be statistically significant, but not be clinically significant, and vice-versa. Unfortunately, clinical significance is not well defined or understood, and many research consumers mistakenly relate statistically significant outcomes with clinical relevance. Clinically relevant changes in outcomes are identified (sometimes interchangeably) by several similar terms including “minimal clinically important differences

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(MCID)”, “clinically meaningful differences (CMD)”, and “minimally important changes (MIC)”.

In general, these terms all refer to the smallest change in an outcome score that is considered “important” or “worthwhile” by the practitioner or the patient8 and/ or would result in a change in patient management9,10.

Changes in outcomes exceeding these minimal values are considered clinically relevant. It is important to consider that both harmful changes and beneficial changes may be outcomes of treatment; therefore, the term “clinically-important changes” should be used to identify both minimal and beneficial differences, but also to recognize harmful changes.

Unfortunately, there are no standards for calculating clinically important changes in outcomes. Clinicians and researchers sometimes have different values for clinically important changes, and minimal changes may be specific to the individual patient. There is some subjectivity in determining clinical significance because of the paucity of research determining clinically significant values, and variations in patient status and goals and clinician experience. Minimal clinically important differences are generally calculated by comparing the difference in an outcome score before and after treatment with an “anchor” score such as global perceived effect score or another measure of the patients perceived change in an outcome.

Some researchers have identified MIC, MCID, and CMD with various outcome measures. It is important to determine clinical significance in a patient population with similar diagnoses and pain levels.

For example, a clinically important change in pain in shoulder pain patients varies between patients with intact rotator cuffs and those with a ruptured rotator cuff.11 Patients with acute pain or higher levels of pain intensity may require less change in pain than chronic pain patients for their changes to be considered clinically important.12 Some researchers have suggested that clinically significant changes can be determined using the standard deviation or standard error of the mean (SEM) within a study. Minimal important changes must be beyond the error of the measuring device to ensure clinical changes were not due to measurement error.

Wyrwich13 reported that the MIC in musculoskeletal disorders was 2.3 or 2.6 times the SEM. To calculate

the MCID, Lemieux et al.14 suggested multiplying the pooled baseline standard deviation scores by 0.2, which corresponds to the smallest effect size.

For example, if the pooled baseline standard deviation is +/- 10, then the MCID is (0.2 x 10) equal to 2. Therefore, a mean difference between groups that is higher than the MCID of 2 is clinically relevant.

However, more research is needed on the method of calculating clinically important changes and on quantifying these changes in patient populations.

EFFECT The most fundamental question of clinical significance is usually, “Is the treatment effective, and will it or should it change my practice?” Some studies use the terms “efficacy” and “effectiveness” interchangeably; however, these terms should be differentiated.

Efficacy is the benefit of an intervention compared to control or standard treatment under ideal conditions, including compliant subjects only. Effectiveness is the benefit of an intervention in a “real-world” defined population, including non-compliant subjects. Treatment efficacy is evaluated using compliant subjects,15,16 while treatment effectiveness includes an ‘intent-to-treat’ analysis of all patients enrolled in the trial, by including subjects who dropped out in the final analysis, thus providing more clinicallyrelevant outcomes.

The effect size is one of the most important indicators of clinical significance. It reflects the magnitude of the difference in outcomes between groups; a greater effect size indicates a larger difference between experimental and control groups. Standardized effect sizes (or standardized mean differences) are important when comparing treatment effects between different studies, as commonly seen in the performance of meta-analyses. Clinical researchers should include standardized effect sizes in their results.

Cohen17 established traditional calculation of effect values based on group differences (change score), divided by the pooled standard deviation in the following equation: Change in Experimental Group vs. control 6 = Stan ndard Deviation of both groups 10

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=0.6 Cohen

Cohen quantified effect sizes that have been operationally described in ranges: <0.2= trivial effect; 0.2-0.5 = small effect; 0.5-0.8 = moderate effect; > 0.8= large effect. Cohen’s effect sizes may be positive or negative, indicating the direction of the effect.

For example, the effect size of 0.6 above would be a “moderate positive effect.” If the effect size were negative (-0.6), the resulting effect would be “moderately negative”.

Treatment effect may also be determined by using “relative risk” or “odds ratio” analysis. The relative risk or “risk ratio” (RR) is the probability of an outcome occurring in a treatment group divided by the probability of an outcome occurring in a comparison group. The odds ratio (OR) is the proportion of subjects in the treatment group with an outcome divided by the proportion of subjects in a comparison group with the outcome. A RR or OR of 1 indicates no difference between the treatment and comparison groups.

Values greater than 1 favor the treatment group, while values less than 1 favor the comparison group.

Relative risk (RR) can also be used to identify clinical effectiveness of an intervention. If a clinician assumes that a 10% improvement in a patient is clinically meaningful, then the number of subjects with at least 10% improvement can be compared to those not reaching the minimal (10%) improvement.

Therefore, the relative clinical effectiveness (assuming an intent-to-treat analysis) would be defined using the following equation: Relative clinical effectiveness= % subjectss with clinically meaningful outcome % subje ects without clinically meaningful outcome If 20% of subjects receiving the intervention reach a 10% improvement, while 80% of subjects receiving the intervention don’t, the relative clinical effectiveness of the intervention is 25%.

The number needed to treat (NNT) provides the number of patients who need to be treated before seeing one patient improve who would not have improved without the intervention. The NNT can infer clinical effectiveness: a high NNT indicates a less effective treatment, and may render the intervention prohibitive. For more information on the NNT and

how to calculate it, the reader is referred to: http:// en.wikipedia.org/wiki/Number_needed_to_treat Effect size, statistical power, and sample size are interrelated. The power analysis determines the number of subjects needed in a study to detect a statistically significant difference with an appropriate effect size.

Statistical power of 80% (0.8) is generally accepted, meaning that 80% of the time, the researcher will avoid Type 2 error (β), where the researcher fails to reject the null hypothesis when there is a difference between groups. Power analysis is usually based on the results of previous studies when the mean differences and SDs are known. In some cases, statistical power can be determined after conclusion of a study in a “post hoc” manner, although determining statistical power before a study begins in an “a priori” manner to estimate sample size is preferred and expected.

A small sample size may demonstrate a lack of statistically significant different results, but still provide results with clinical significance. Even a study powered at 80% still has a 1 in 5 chance of creating a Type 2 error (false negative).7 A small sample size limits statistical power; while larger sample sizes provide more power to detect statistically significant differences. While larger sample sizes are obviously preferred in a clinical study to capture a true representation of the clinical population being studied, larger samples sizes can lead to statistically significant differences that remain clinically insignificant.

CONFIDENCE INTERVALS One of the most meaningful, yet misunderstood and underutilized statistics in interpreting clinical research may be the confidence interval (CI). The CI is the certainty that a range (interval) of values contains the true, accurate value of a population that would be obtained if the experiment were repeated.

Fortunately, more researchers and reviewers are using CIs to report results of clinical trials in the literature; however, clinicians need to understand the clinical interpretation and value of reporting the CI. Confidence intervals are appropriate for reporting the results of clinical trials because they focus on confidence of an outcome occurring, rather than accepting or rejecting a hypothesis.18 In addition, the CI provides information about the magnitude and direction of an effect, offering more clinical value

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than answering a hypothesis-based question. Greenfield et al19 noted that CIs “are statements about belief in the statistical process and do not have probability implications.” Rather, probability would be determined by interpretations of statistical significance.

In contrast, CIs offer more precision of the estimate of the true value of an unknown because it includes the range of uncertainty.

The CI represents the researchers level of confidence that the true value in a representative population is contained within the interval. From a clinical perspective, the CI is the likely range containing the value of a true effect of treatment in an average subject.6 A CI is reported as a range or interval describing the lower and upper values (“boundaries”) of uncertainty, also known as the “margin of error.” While some clinicians assume that the CI represents the range of scores (i.e., subjects improved by up to the value of the upper boundary or declined by the value of the lower boundary), this is not correct. Furthermore, the CI should not be confused with standard deviation, which is used to describe the variability of a mean score within a sample. CIs are reported with a “point estimate” (PE) from the sample tested from the population. The PE is a specific value (which may be a sample mean, difference score, effect size, etc), but does NOT represent a “true” value; rather, it represents the “best estimate” of the true value from the average of the sample20 and should be viewed in consideration of the range of the CI. CIs are based on a specific level of confidence. Most CIs are calculated using 95% confidence, meaning if the experiment were repeated 100 times, the true value would be obtained within that interval 95 times. However, Hopkins6 recommends using a CI of 90%, which provides a wider interval and greater margin of error.

In the literature, researchers report the PE and interval, and a range of uncertainty (CI) with a confidence level, which may be reported by, “mean value = 0.3 (95% CI, -0.1 to 0.7)”. A CI may also be reported as a “+/-” value, such as 0.3 +/- 0.4. Clinically interpreted, these notations would infer: The between group difference in this study sample was 0.3, with the true value represented in a range of -0.1 to 0.7 in the population. Subsequent notations within a manuscript may simply report the point estimate and CI, as in, “0.3(-0.1,0.7).” Clinical researchers are encouraged to

clearly report descriptive means and standard deviations along with mean differences, effect sizes, and CIs, as suggested in Table 2.

Graphical representation of CIs often helps demonstrate their clinical value and interpretation. Figure 2 provides and example of several types of graphs representing point estimates and CIs. A line graph (Figure 2b) is typically recommended because of its ease of interpretation and comparison.

Unfortunately, some authors do not report CIs; however, several free calculators are available online, including one from PEDro (http://www.pedro.org. au/english/downloads/confidence-interval-calculator/). The CI is calculated from the representative sample value (PE), the standard error of the mean, and the “confidence coefficient,” which is determined from the z-value corresponding to sample size and a specific confidence level (for example, a 95% CI generally has a 1.96 confidence coefficient value). The CI is determined by using the formula: CI = Point estimate +/- confidence coefficient * standard error.

Therefore, the upper and lower bounds of the CI represent the equivalent “+/-” of the confidence values. The standard error is calculated by the standard deviation divided by the square root of the sample size. The smaller the standard error of the mean, the narrower the confidence interval, and the more accurate the estimate.

Table 2. Suggested format for reporting data in clinical studies Mean + SD Pre

Post

Mean Diff + SD

% Diff

Effect Size

CI (95%)

p-value

Experimental Control

Figure 2. Confidence intervals presented as a curve graph (a), line graph (b), and bar graph (c), each representing a point estimate and CI of 0.3(-0.1,0.7).

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There are several things to consider when evaluating a CI for assessments of clinical significance, including the type of point estimate; value and location of the point estimate and CI relative to zero; harm/benefit potential; the width and symmetry of the CI; and the MCID. Type of point estimate. Point estimates and CIs can be used to demonstrate several types of outcome values, including sample means, group differences, effect sizes, and odds/risk ratios (Figure 3).

It’s important to note what the PE represents when interpreting a CI. Evaluating a mean difference within a CI is different than evaluating an effect size with a CI. For example, interpreting the CI of a mean value of a sample is relatively straight-forward; the CI represents the range of possible values containing the true value of the population. For CIs representing effect sizes and differences between groups, interpretation requires more considerations. The PE of an effect size provides the context to help determine if the result is strong or weak, as well as whether it is clinically useful19. The location and size of the CI also are important to consider.

Point estimate and CI relative to 0. The relationship of the point estimate and CI to zero provides valuable information in CIs representing effects or group differences. Obviously, point estimates further from 0 represent more effect or difference, either positive

Figure 3. Graphical representation of different types of CI: point estimate (a); effect size (b); odds ratio (c).

or negative. Similarly, the closer to 0, the less group difference or effect. Interestingly, CIs can be used with hypothesis testing and are therefore related to statistical significance. If the CI of a mean difference, effect size, OR, or RR does not contain a value of 0, the results are significant. Other types of point estimates, such as sample means, may contain 0 and still be significant statistically. It’s important to note that studies with large effect sizes and small CIs that do not cross zero have the most clinical significance.

Harm/Benefit potential. Using Cohen’s d-value (discussed earlier) or standardized effect sizes, the PE and CI can provide information on the magnitude and direction of the effect as well as potentially beneficial or harmful effects. The location of the point estimate determines if the outcome is considered harmful, beneficial, or trivial1 (Figure 4).

A positive effect size greater than 0.2 is considered beneficial, while a negative effect size less than -0.2 is considered harmful. Effect sizes between -0.2 and 0.2 are trivial in size.

Width and symmetry of the CI. The width of the CI provides clarity regarding the magnitude of the treatment effect or group differences. A wide CI (usually representing a small sample size) has more uncertainty and may suggest that study findings are unclear if it spans all 3 levels of magnitude (harmful,

Figure 4. Harmful, trivial, and beneficial ranges within a CI representing effect sizes. Adapted from Batterham & Hopkins2.

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trivial and beneficial). With small sample sizes, CIs are more important than examination for statistically significant differences, which are affected by sample size. In contrast, large samples yield narrow CIs, which help clinicians determine the smallest amount of benefit to justify therapy within a smaller margin of error. When interpreting a study result with CIs, an outcome may be statistically insignificant and yet clinically significant in a wide CI. For example, consider a between group difference CI of 0.8(-3,19) in a small population. While the CI contains 0 (statistically insignificant), the CI remains relatively large, particularly in the positive range; therefore, the conclusion should be that the intervention might be beneficial, but larger sample sizes are needed.

While the difference between the point estimate and the upper and lower boundaries is usually equal (the “+/-” value), the CI may not be symmetrical. For example, when the CI of odds ratios are reported, there is a natural skew in the interval because the CI is calculated on a natural log value. In this case, the actual upper and lower boundaries of the CI would be reported, rather than using a “+/-” value with the point estimate.

MCID. It’s helpful to know the MCID when interpreting the CI. By comparing the treatment outcome with the MCID, clinicians can determine if the treatment will be beneficial or harmful to their patients.

Combining the MCID with the CI is a very valuable strategy to be utilized for clinical interpretation, especially when hypothesis testing reveals no statistically significant differences.

If the MCID falls within the CI, the treatment may be clinically effective regardless of the PE. Recall that the CI represents the range of values in which the true value exists within a population if the study were repeated. Obviously, if the PE exceeds the MCID, the treatment was effective. In the between group differences CI example described previously, 0.3(-0.1, 0.7), if the MCID is known to be 0.2, the treatment may be clinically effective since it exceeds the point estimate.

If the MCID falls within the CI, yet remains below the point estimate, the clinician needs to decide if the treatment is appropriate or not. In an example of a clinical trial, two groups of patients with shoulder pain were compared: one received traditional therapy (control group) for 6 weeks, while another group (experimental) received a different therapy

for 6 weeks. A primary outcome of shoulder external rotation range of motion (ROM) was measured before and after the treatment and compared within and between groups (Repeated-Measures ANOVA for statistically significant differences). The experimental group increased in their external rotation ROM on average from 60 to 68 degrees (a difference of 8 degrees), while the control group increased from 60 to 64 degrees (a difference of 4 degrees); therefore, the mean difference between groups is 4 degrees.

The statistical analysis revealed no significant difference between groups; however, clinical interpretation of the results may lead to a different conclusion.

Assume an increase of 10 degrees of external rotation ROM would be the MCID to convince a clinician to change their treatment. In the clinical example above, the mean increase in external rotation ROM in the experimental group was 8 degrees, falling below the MCID, which may not be enough for a clinician to change their treatment. However, if the CI was (4,12), note that the MCID (10 degrees) still falls within the CI; thus it is possible for some patients to reach and even exceed the MCID to 12 degrees (the upper bound of the CI) (Figure 5). If the confidence interval is not harmful and beyond trivial, clinicians might consider the treatment in some patients. The clinician may consider that while the point estimate of the sample did not reach minimal clinical importance, the CI still contains the MCID within the true population, and further research with larger samples are warranted.

Figure 5. Line graph of CI 8(4,12) and MCID of 10. Note that the CI still contains the MCID; therefore, the treatment may be beneficial but a larger sample is needed.

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It is important to consider the population being studied when interpreting CIs. For example, Hopkins et al21 discussed how competitive elite athletes value very small percentages of improvement for performance enhancement: a 1% increase in speed during a 100 meter sprint may be the difference between first and second place. They suggested that laboratory-based studies or studies on non-elite athlete cohorts cannot be generalized for performance enhancement of elite athletes, and recommended reporting percent changes as well as confidence intervals for utilization in performance enhancement outcomes. For example, if a 1% improvement is meaningful, and a RCT shows no significant difference between two groups of elite athletes, but the CI contains the meaningful improvement (eg, 0.5 to 1.5%), there exists a possibility that an athlete would benefit from the intervention. In contrast, a CI that does not contain the meaningful difference (eg, 0.1 to 0.9%) may not be worthy of using even if the results were statistically significant.

Meta-analyses use CIs to describe the effectiveness of treatments by pooling data from several homogenous studies in an effort to pool standardize effect sizes, often using Cohen’s d-value or other standardized difference. Most meta analyses use a “forest plot” rather than a bell-shaped curve to graphically represent the effects of various studies. Forest plots use lines or bars to represent various CIs of different studies and a “summary point estimate,” representing the overall effect of the pooled studies. This type of graphical representation (Figure 6) is often useful to get the “total picture” of the multiple studies contained within in a meta-analysis.

MAGNITUDE-BASED INFERENCES Because of the aforementioned limitations of hypothesis testing in clinical research, researchers are slowly moving away from relying solely on hypothesis testing to interpretation of other outcomes in clinical studies. Magnitude-based inferences (MBI) are now being used to avoid limitations of traditional statistical analysis (null and directional hypothesis testing) in relation to clinical significance.6 Magnitude-based inferences use qualitative rather than statistical descriptions of study outcomes.

Confidence intervals can provide magnitude of differences or effect through MBI. As stated earlier, Batterham and Hopkins1 suggest three levels of magnitude of change: harmful, trivial, and beneficial. Obviously, these three levels are important for clinicians to consider when making evidence-based decisions; the location and width of the CI on an outcome continuum can be clinically interpreted using these three levels. The outcome continuum should include the threshold value for beneficial (MCID, MIC, etc) as well as harmful outcomes.

Hopkins et al6 recommend more qualitative statements (such as “probably,” “possibly,” and “likely”) to reflect the uncertainty of the true value, while avoiding the use of “statistical jargon.” These qualitative terms can be combined with the three levels of magnitude (beneficial, harmful, trivial) in order to further refine the possible outcome value represented by the CI (Figure 7). Traditional statistical packages do not provide magnitude-based inferences; instead a spreadsheet can be used to assess and infer the clinical magnitude.22 Obviously, the MBI that represent harmful or beneficial outcomes provide more clinical information for decision-making than simply stating, “There was no statistically significant difference.”

In their article, Batterham and Hopkins1 summarize the value of MBI in clinical interpretation of research:

Figure 6. Forest plot used in meta-analysis studies to summarize the effects of different studies.

“A final decision about acting on an outcome should be made on the basis of the quantitative chances of benefit, triviality, and harm, taking into account the cost of implementing a treatment or other strategy, the cost of making the wrong decision, the possibility of individual response to the treatment, and the possibility of harmful side effects.”

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Figure 7. Using Magnitude-based inferences to describe CIs and clinical relevance.

CLINICAL INTERPRETATION Understanding and interpreting CIs can help clinicians make better decisions. As opposed to laboratory experiments when conditions and variables are wellcontrolled, clinical research is often confounded by subject variability, measurement error, and smaller sample sizes, among other factors. Therefore, reliance on hypothesis testing is of limited value in clinical research. A more practical and useful method of analysis in clinical research utilizes confidence intervals and magnitude-based inferences. Table 3 provides a checklist for clinical interpretation of rehabilitation research.

Suggestions for researchers and clinicians to improve clinical interpretation of published research include: 1. For validity, provide details on study design, especially specific treatment protocols that are reproducible, including the prescription and progression.

Use the PEDRO scale (http://www.pedro.org.au/ english/downloads/pedro-scale/) to guide internal validity.

2. Provide power analysis (preferably a priori) to ensure appropriate sample size to avoid a Type 2 error.

3. Report magnitude of change in percentages as well as absolute and standardized values.

4. Report effect sizes using standardized mean differences (Cohen’s d), odds ratio, or risk ratio calculations using representative terms such as trivial, small, moderate, and large.

5. Use CIs to report point estimates including mean differences and treatment effect. Rather than simply stating, “p<.05”, state, “the treatment improved ROM by an average of 10 degrees with a 95% CI between 5 and 15 degrees.”

Table 3. Checklist for clinical interpretation of rehabilitation research

Descriptive Statistics

• • • • • • • •

Effect Sizes Confidence Intervals

• •

Magnitude Based Inferences

•

Internal Validity External Validity Statistical Power Outcome Measures

Appropriate research design Review for sources of bias Protocol explained and reproducible Relevant Population Adequate sample size reported Valid & Reliable measures Minimal clinically important differences noted Mean, standard deviation, percent change and standardized values reported Standardized and reported CI used to report means, group differences, effect sizes and/or odds ratios Outcomes reported in terms of trivial, harmful, or beneficial using MBI descriptors

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6. Provide clinical interpretation of the CI with regards to the point estimate and width. For example, “While statistically insignificant, the findings are unclear and larger study samples are needed.”

7. Provide results relative to clinically meaningful differences or minimal clinically important changes.

8. Provide results in terms of magnitude-based inferences where possible, using terms relative to harmful, beneficial, or trivial, including qualitative terms such as “probably” and “almost certainly.”

CONCLUSION Clinical researchers need to present clinically meaningful results, and clinicians need to know how to interpret and implement those results in their evidence-based approach to clinical decision making.

Interpretation of clinical research outcomes should not be based solely on the presence or absence of statistically significant differences. Because of the heterogeneity of patient samples, small sample sizes, and limitations on hypothesis testing, clinicians should consider other clinically-relevant measures such as effect size, clinically meaningful differences, confidence intervals, and magnitude-based inferences.

REFERENCES 1. Batterham AM, Hopkins WG. Making meaningful inferences about magnitudes. Int J Sports Physiol Perform. Mar 2006;1(1):50-57.

2. Page P. Research designs in sports physical therapy.

International journal of sports physical therapy. Oct 2012;7(5):482-492.

3. Group OLoEW. The Oxford 2011 Levels of Evidence.

2011; http://www.cebm.net/index.aspx?o=5653.

Accessed August 29, 2014.

4. Grant HM, Tjoumakaris FP, Maltenfort MG, Freedman KB. Levels of Evidence in the Clinical Sports Medicine Literature: Are We Getting Better Over Time? Am J Sports Med. Apr 23 2014;42(7):1738-1742.

5. de Morton NA. The PEDro scale is a valid measure of the methodological quality of clinical trials: a demographic study. Aust J Physiother. 2009;55(2):129133.

6. Hopkins WG, Marshall SW, Batterham AM, Hanin J. Progressive statistics for studies in sports medicine and exercise science. Med Sci Sports Exerc. Jan 2009;41(1):3-13.

7. Sainani KL. Putting P values in perspective. PM & R : the journal of injury, function, and rehabilitation. Sep 2009;1(9):873-877.

8. Copay AG, Subach BR, Glassman SD, Polly DW, Jr., Schuler TC. Understanding the minimum clinically important difference: a review of concepts and methods. Spine J. Sep-Oct 2007;7(5):541-546.

9. Jaeschke R, Singer J, Guyatt GH. Measurement of health status. Ascertaining the minimal clinically important difference. Control Clin Trials. Dec 1989;10(4):407-415.

10. Guyatt GH, Osoba D, Wu AW, Wyrwich KW, Norman GR, Clinical Significance Consensus Meeting G. Methods to explain the clinical significance of health status measures. Mayo Clin Proc. Apr 2002;77(4):371-383.

11. Holmgren T, Oberg B, Adolfsson L, Bjornsson Hallgren H, Johansson K. Minimal important changes in the Constant-Murley score in patients with subacromial pain. J Shoulder Elbow Surg. Apr 13 2014.

12. Ostelo RW, de Vet HC. Clinically important outcomes in low back pain. Best practice & research. Clinical rheumatology. Aug 2005;19(4):593-607.

13. Wyrwich KW. Minimal important difference thresholds and the standard error of measurement: is there a connection? Journal of biopharmaceutical statistics. Feb 2004;14(1):97-110.

14. Lemieux J, Beaton DE, Hogg-Johnson S, Bordeleau LJ, Goodwin PJ. Three methods for minimally important difference: no relationship was found with the net proportion of patients improving. Journal of clinical epidemiology. May 2007;60(5):448-455.

15. Helewa AW, J. M. Critical evaluation fo research in physical therapy. Philadelphia: Saunders; 2000.

16. Portney LG, Watkins MP. Foundations of clinical research: applications to practcie. 3rd ed. New Jersey: Pearson Prentice Hall; 2009.

17. Cohen J. Statistical power analysis for the behavioral sciences. 2nd ed. New Jersey: Lawrence Eribaum; 1988.

18. Borenstein M. The case for confidence intervals in controlled clinical trials. Control Clin Trials. Oct 1994;15(5):411-428.

19. Greenfield ML, Kuhn JE, Wojtys EM. A statistics primer. Confidence intervals. Am J Sports Med. Jan-Feb 1998;26(1):145-149.

20. Drinkwater E. Applications of confidence limits and effect sizes in sport research. Open Sports Sciences J. 2008;1:3-4.

21. Hopkins WG, Hawley JA, Burke LM. Design and analysis of research on sport performance enhancement. Med Sci Sports Exerc. Mar 1999;31(3):472-485.

22. Hopkins WG. A spreadsheet for deriving a confidence interval, mechanistic inference and clinical inference from a p value. Sportscience.

2007;11:16-20.

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