Knee Pain and Lack of Hip Strength

NASM Research Update Relationship Between Hip Strength and Trunk, Hip and Knee Kinematics During Jump Landing Tasks in Individuals with Patellofemoral Pain

Boling M, Padua D. International Journal Sports Physical Therapy.

2013 Oct;8(5):661-9.

Introduction • Patellofemoral pain (PFP) is a common cause of chronic knee pain among physically active individuals • Even though PFP is common among active individuals, its cause is not well understood • Multiple biomechanical factors have been theorized – Abnormal anatomical alignment (e.g., increased Q angle) – Decreased strength of hips and thighs – Faulty lower body mechanics during dynamic movements – Frontal and transverse plan motion at hip and knee

Purpose • The purpose of this original research study is to: 1. Determine if a relationship exists between hip muscle strength and frontal and transverse plane motion at the hip and knee (i.e., medial knee displacement, knee valgus) 2. Determine the relationship between concentric and eccentric hip muscle strength and ipsilateral (same-side) trunk flexion during a jump-landing task in individuals with PFP

• Hypothesis –. Decreased strength of the hip abductors, extensors and external rotators would increase medial knee displacement and knee valgus and ipsilateral trunk flexion during jump-landing tasks

Participants •

15 subjects with PFP volunteered – 10 females – 5 males – Mean age = 27.3 years + 4.1 years – Mean height = 171.3 cm + 8.3 cm – Mean mass = 72.8 kg + 17.4 kg

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Exclusion criteria – History of knee surgery – Evidence of other trunk, hip or knee pathology – Age greater the 40 years – Age less than 18 year

Procedures •

A 3-D motion analysis system was used to assess trunk, hip, and knee kinematics during a jump-landing task

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An isokinetic dynamometer was used to assess concentric and eccentric strength of the hip musculature – Hip abduction – Hip extension – Hip external rotation

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Correlation analyses were done to determine the relationships between hip muscle strength and peak frontal and transverse plane hip and knee kinematics and ipsilateral trunk flexion

Results & Limitations • The authors concluded: – Decreased eccentric strength of the hip external rotators and abductors was significantly correlated to increased frontal plane motion at the hip and trunk, respectively

• Limitations – Lack of control group – Unequal number of female and male subjects – Low sample size

Key Findings •

Decreased eccentric strength of the hip external rotators and abductors was significantly correlated to increased frontal plane motion at the knee and hip for subjects with PFP

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A decrease in the eccentric torque producing capabilities of the hip abductors is related to an increase in frontal plane motion of the trunk towards the affected or most affected side of pain

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These faulty movement patterns can result in increased knee valgus and in turn PFP

Conclusions • Increased frontal plane motion of the knee, hip and trunk during jump-landing tasks warrants the use of strengthening exercises for hip musculature, particularly: – Gluteus Medius – Gluteus Maximus

• Clinicians should evaluate hip eccentric strength and movement patterns for patients with PFP

Note for Certified Personal Trainers • Faulty movement patterns will indicate the possibility of muscle imbalances (muscle tightness and muscle weakness) • Certified Personal Trainers should perform movement screens on clients to determine faulty movement patterns – Example movement screens – Overhead Squat Assessment – Single-leg Squat Assessment – Landing Error Scoring System (LESS) Test