Journal of Strength and Conditioning Research, 2004, 18(3), 432–440 q 2004 National Strength & Conditioning Association
EFFECT OF 12 WEEKS OF WRIST AND FOREARM TRAINING ON HIGH SCHOOL BASEBALL PLAYERS DAVID J. SZYMANSKI, JESSICA M. SZYMANSKI, JOSEPH M. MOLLOY,
AND
DAVID D. PASCOE
Department of Health and Human Performance, Auburn University, Auburn, Alabama 36849.
ABSTRACT. Szymanski, D.J., J.M. Szymanski, J.M. Molloy, and D.D. Pascoe. Effect of 12 weeks of wrist and forearm training on high school baseball players. J. Strength Cond. Res. 18(3):432– 440. 2004.—This study examined the effect of 12 weeks of wrist and forearm training on male high school baseball players (mean age 5 15.3 6 1.1 years). Participants (N 5 43) were tested for 10 repetition maximum (RM) wrist barbell flexion, wrist barbell extension, dominant (D) and nondominant (ND) hand-forearm supination, D and ND forearm pronation, D and ND wrist radial deviation, D and ND wrist ulnar deviation, D and ND grip strength, and a 3RM parallel squat (PS) and bench press (BP). Group 1 (n 5 23) and group 2 (n 5 20), randomly assigned by a stratified sampling technique, performed the same resistance exercises while training 3 days a week for 12 weeks according to a stepwise periodized model. Group 2 also performed wrist and forearm exercises 3 days a week for 12 weeks to determine if additional wrist and forearm training provided further wrist and forearm strength improvements. All wrist and forearm strength variables were measured before and after 12 weeks of training. The 3RM PS and BP were measured at 0 and after 4, 8, and 12 weeks of training. Both groups significantly increased wrist and forearm strength (kg 6 SD) except 10RM D and ND forearm supination for group 1 (p , 0.05). Group 2 showed statistically greater improvements (p , 0.05) in all wrist and forearm strength variables than did group 1 except for D and ND grip strength. Predicted 1RM (kg 6 SD) PS and BP increased significantly (p , 0.05) after weeks 4, 8, and 12 for both groups. These data indicate that a 12-week stepwise periodized training program can significantly increase wrist, forearm, PS, and BP strength for both groups. Additionally, group 2 had further wrist and forearm strength gains. KEY WORDS. athlete, grip strength, periodization, resistance training
INTRODUCTION rist and forearm strength is required to perform well in a variety of sports and recreational activities that require holding or throwing an implement. In particular, baseball coaches and hitting instructors have long believed that to be a good hitter (i.e., swing a baseball bat with control and velocity) requires strong wrists and forearms. Traditionally, baseball players have performed very high repetition (i.e., 15–30 repetitions) wrist and forearm exercises. This repetition range would be described as muscular endurance training (2) and would not be appropriate to develop muscular strength needed in the powerful actions of swinging a bat in the game of baseball. Conversely, research (4, 22) has demonstrated that low-repetition, high-intensity training (i.e., 2–8 repetitions) will increase muscular strength. However, when training the wrist and forearms, it must be stated that the biaxial radiocarpal (wrist) joint is considered weak relative to other joints (i.e., knee) that are surrounded by greater muscle mass (11). Forceful rotational distal ra-
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dioulnar injuries are typically associated with chondromalacia of the ulnar head, whereas stressful ulnar deviation performed during baseball-bat swinging is associated with ulnocarpal impingements with partial tears of the triangular fibrocartilage (11). Therefore, when planning a strength program of the wrists and forearms, one should design a program that will accomplish the desired strength gains but not jeopardize the integrity of the joints and cause potential injury. To date, no scientific research has evaluated the effect of wrist and forearm training on wrist and forearm strength of male high school baseball players. The purpose of this study was to measure the wrist and forearm strength after completing a 12-week resistance-training program.
METHODS Experimental Approach to the Problem
This study was designed to answer 3 major questions: Can significant increases in wrist and forearm strength be obtained in high school baseball players with a 12week resistance-training program, and does this training need to be wrist and forearm specific? Given the time (hours per week) limitations for team practices at both the high school and the collegiate levels, are these resistance-training programs justified? To our knowledge, the tests performed to measure wrist and forearm strength in this study have not been used in previous research, although they are routinely performed by athletes in strength facilities at the high school, collegiate, and professional levels. The individual wrist and forearm tests were chosen to represent the 6 movements of the wrist and forearm. All the wrist and forearm strength assessments, in addition to parallel-squat (PS) and bench-press (BP) strength, were measured isotonically to compare the strength gains of the 2 groups within and among baseball players. Over the past 2 years, the lead author has used these 6 wrist and forearm measures without injury with reproducible test results with the university baseball team he trains. Furthermore, all participants in this study were shown and verbally told how to perform each exercise properly during the initial meeting before the study began. During the familiarization sessions, the pre- and posttraining testing sessions, and throughout the 12week study, participants were continually instructed and observed by the lead author and his assistants to perform the exercises properly according to the guidelines described in this paper. Subjects
Forty-six male high school baseball players from 1 team between the ages of 14 and 18 years volunteered for this
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Weight (kg)
Body fat (%)
attend 90% (n 5 33) of the total 36 exercise sessions to be included in the study. Participants could not miss on subsequent days or they were dropped from the study. Procedures
Table 1. Mean (6SD) baseline descriptive data for groups. Group
Age (y)
Height (cm)
Group 1 (n 5 23) Group 2 (n 5 20)
15.3 (1.2)
176.6 (7.8)
72.3 (13.4)
10.5 (5.6)
15.4 (1.1)
179.0 (5.0)
72.1 (7.9)
10.1 (5.0)
study. All parents and volunteers completed a written informed consent in accordance with the Auburn University Institutional Review Board’s guidelines before being permitted to participate. Participants answered a modified Physical Activity Readiness Questionnaire (PAR-Q), which was immediately evaluated by the lead author to eliminate those who might be at a medical risk of injury. The PAR-Q consisted of questions addressing potential cardiovascular, muscular, bone, joint, and medication concerns. If a contraindication for participating in an exercise program was noted, the individual was not allowed to participate in the study. Additionally, participants completed a Descriptive Data Questionnaire, which described their past playing and exercising experiences. Three participants did not complete the study for reasons unrelated to the project. Participants were separated by academic grades (freshman, sophomore, junior, and senior) and body-mass categories (45.4–58.6, 59.1–72.3, 72.7–85.9, 86.41 kg), which were modified from boys wrestling weight classifications used by the Alabama High School Athletic Association (1). To keep the number of participants per group large enough for statistical power and maintain homogeneity of variance between the 2 groups (age and body mass), the participants were randomly assigned to 1 of 2 exercise groups by a stratified sampling technique to control for selection bias to internal validity. Participants’ descriptive data are listed in Table 1. Group 1 (n 5 23) and group 2 (n 5 20) both performed a linear periodized resistance-training program 3 days a week for 12 weeks. Group 2 also performed wrist and forearm exercises 3 days a week for 12 weeks. The participants had to
During the first week of the study, before assessment of the 10 repetition maximum (RM) wrist and forearm movements, 3RM PS, and BP, all participants underwent 2 low-resistance (5 3 5RM) strength-training sessions to become familiar with the exercises and to practice proper lifting and spotting techniques. All participants performed a regimen of full-body stretching exercises before all training and testing sessions. Participants were encouraged to ask questions and freely state their concerns about the training program. Each participant received a training log that had photos and written descriptions of each exercise inside that promoted proper exercise and spotting techniques. Also, the lead author and 2 assistants provided constant supervision, observing the participants and verbally reminding them daily of proper lifting and spotting techniques. Pre- and posttesting for height, body mass, body composition, 10RM for wrist barbell flexion, wrist barbell extension, dominant (D) and nondominant (ND) hand-forearm supination, D and ND forearm pronation, D and ND wrist radial deviation, D and ND wrist ulnar deviation, D and ND grip strength, and 3RM PS and BP was conducted on 1 day. The sequence of tests, protocols, and rest periods for the posttest was consistent with those of the pretest. Table 2 displays an overview of the experimental time line. For control of outside influences, all participants were instructed to consume a normal diet and abstain from additional resistance training and taking ergogenic aids (e.g., creatine, amino acids, metabolite b-hydroxy b-methylbutyrate monohydrate) during the 12week research period. Each participant recorded pre- and posttesting food and drink consumption the day before and the day of strength testing in a Diet Log to assure that his normal diet was maintained. Training Protocols
Resistance training for both groups was performed 3 days a week for 12 weeks according to a stepwise periodized
Table 2. Experimental time line.* Pretraining Sunday First meeting Informed consent PAR-Q Descriptive Data Questionnaire
Week 1 Tuesday, Thursday, Sunday Begin training protocol
Week 4 Sunday 3RM: PS and BP
Week 8 Sunday 3RM: PS and BP
Week 12 and posttraining Sunday Height and body mass Body composition 3RM: PS and BP 10RM: wrists and forearms Grip strength
Tuesday and Thursday Familiarization days Sunday Height and body mass Body composition 3RM: PS and BP 10RM: Wrists and forearms Grip strength * RM 5 repetition maximum; PS 5 parallel squat; BP 5 bench press; PAR-Q 5 Physical Activity Readiness Questionnaire.
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Table 3. Training protocols.* Groups 1 and 2 Weeks 1–4
Core Assistance
Sets
Reps
2 WU 3 3
10 10 10
Weeks 5–8 % 1RM 45, 50 65, 70, 75
Sets
Reps
2 WU 3 3
10 8 8
Weeks 9–12 % 1RM 45, 50 70, 75, 80
Sets
Reps
2 WU 3 3
10 6 6
% 1RM 45, 50 75, 80, 85
Group 2 Forearm†
2
12
2
10
2
8
* Adapted with modifications from Baker et al. (4) and Stone et al. (22). Reps 5 repetitions; RM 5 repetition maximum; WU 5 warm-up. Groups 1 and 2 trained using percentage of predicted 1RM values according to load assessments by Wathen (24). Rest time between all sets 5 90 seconds. † Resistance was heavy enough so that the last 2 repetitions of each set were difficult.
Table 4. Schedule of exercises. Groups 1 and 2 Exercise
Tuesday
Parallel squats* Stiff-leg deadlift† Barbell bench press* Bent-over row† Barbell shoulder press† Lying triceps extension† Barbell biceps curl†
Thursday Sunday
X X X X X X X
X X X X X
X X X X X X X
X X X X X X
X X X X X X
X X X X X X
Group 2 Straight bar wrist curls‡ Straight bar reverse wrist curls‡ Standing plate squeeze‡ Standing radial deviation‡ Standing ulnar deviation‡ Seated pronation/supination‡ * Core exercise. † Assistance exercise. ‡ Wrists and forearm exercises.
method similar to previous research (4, 21, 22). Two warm-up sets of 10 repetitions for the core strength exercises (PS and BP) were completed to prepare the participants before performing the more demanding 3 working sets. Set workloads were progressively increased every 4 weeks during the study after having 3RM PS and BP reassessed. Additionally, various assistance exercises were performed to make the training more comprehensive and realistic to the off-season resistance-training programs of high school baseball players. Furthermore, participants in group 2 performed wrist and forearm exercises 3 days a week for 12 weeks. Training protocols and schedule of exercises are displayed in Tables 3 and 4. Great detail was taken to describe how each exercise was executed. Proper technique of each exercise was determined by the following protocols. Wrist Barbell Flexion
Participants were seated on a flat bench with their feet on the floor and straddling either side of the bench. Their torso was flexed from their waist while resting their forearms in a supinated position on the flat bench. A neoprene wrap was secured together around the cubital fossa
(upper part of the anterior forearms just below the elbow joint) and flat bench so the participants’ arms were isolated and could use only the forearm flexors (flexor carpi radialis, flexor carpi ulnaris, and palmaris longus). Next, a goniometer was lined up with the midline of the radius and the extended first metacarpal of the flexed wrist to record each participant’s full, flexed position. Then, participants were instructed to warm up with a light resistance (barbell) that easily allowed 15 repetitions. The participants were required to lift the barbell to the position recorded for wrist flexion to be counted as a successful repetition. They were provided with 2 minutes of rest between all sets. Participants continued warming up with a load that easily allowed them to complete 12 repetitions. On the basis of the previous warm-up set, assistants then estimated a conservative, near 10RM load that allowed the participant to complete 10 repetitions by adding 4.5–9.1 kg or 5–10% for wrist flexion. Assistants then made a load increase of 4.5–6.8 kg for wrist flexion. Participants were then instructed to attempt a maximal 10RM. If a participant was not successful, the load was decreased by subtracting 2.3–4.5 kg or 2.5–5.0% for wrist flexion. Assistants were instructed to continue increasing or decreasing the load until a participant could complete 10RM with proper exercise technique. Ideally, each participant’s 10RM was measured within 4 testing sets. Wrist Barbell Extension
Participants were seated on a flat bench with their feet on the floor and straddling either side of the bench. Their torso was flexed from the waist while resting their forearms in a pronated position on the flat bench. A neoprene wrap was secured together around the brachioradialis (upper part of the posterior forearms just below the elbow joint) and flat bench so the participants’ arms were isolated and could use only the forearm extensors (extensor carpi radialis longus, extensor carpi radialis brevis, and extensor carpi ulnaris). Next, a goniometer was lined up with the midline of the ulna and the extended fifth metacarpal of the extended wrist to record each participant’s full, extended position. Then, participants were instructed to follow the same procedures used to perform the 10RM wrist barbell flexion. Forearm Supination
Each participant’s D hand was measured first. The participant’s arm and shoulder were placed in a neoprene
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sleeve and tightly secured to his torso. With the participant’s shoulder adducted and neutrally rotated, elbow flexed at 908, the assistant wrapped and secured a neoprene band around the upper arm and opposite side of the upper torso so that the participant’s arm was held tightly to his side. This isolated the use of the supinators (biceps brachii and supinator) and brachioradialis. Each participants sat in a standard chair (46-cm high) with his shoulder and elbow in the position described above, resting on a table, forearm in neutral position (08) and wrist between 0 and 158 of ulnar deviation. A goniometer was lined up with the vertical line (08) formed by the extended fingertips and the horizontal line (80–1008) formed by the extended fingertips after pronating the wrist through a full range of motion (ROM). Then the participants were instructed to hold an Olympic plateloaded dumbbell vertically (08) by the handle in 1 hand. The vertical line formed by the second flexed knuckles (second proximal interphalangeal joints) surrounding the dumbbell was at 08. After pronating to the participants’ full ROM (80–1008), the participants supinated the dumbbell to the starting vertical (08) position for the repetition to be successfully recorded. Participants were instructed to warm up with a light resistance (dumbbell) that easily allowed 15 repetitions. They were then provided with 2 minutes of rest between all sets. On the basis of the previous warm-up set, assistants then estimated a conservative, near-10RM load that allowed the participant to complete 10 repetitions by adding 2.3–4.5 kg or 2.5–5.0% for forearm supination. Assistants were instructed to make a load increase of 1.1–2.3 kg or 1.5–2.5% for forearm supination. Participants then attempted a maximal 10RM. If a participant was successful, he was given a 2minute rest period, and the load was increased by adding 1.1–2.3 kg or 1.5–2.5% for forearm supination. If a participant failed, he was provided with a 2-minute rest period, and the load was decreased by subtracting 1.1–2.3 kg or 1.5–2.5% for forearm supination. Assistants were instructed to continue increasing or decreasing the load until a participant could complete 10RM with proper exercise technique. Ideally, each participant’s 10RM was measured within 4 testing sets. After completing the 10RM test for the D hands, participants’ ND hands were tested. Forearm Pronation
Each participant’s D hand was measured first. The participant’s arm and shoulder were secured by the same procedure as for forearm supination. The participant’s shoulder and elbow positions were the same as the forearm supination. This isolated the use of the pronators (pronator teres and pronator quadratus) and flexor carpi radialis. Each participant sat in a standard chair (46-cm high) with his shoulder adducted and neutrally rotated, elbow flexed at 908 and resting on a table, forearm in neutral position (08), and wrist between 0 and 158 of ulnar deviation. A goniometer was lined up with the vertical line (08) formed by the extended fingertips and the horizontal line (80–1008) formed by the extended fingertips after supinating the wrists through a full ROM. Then, the participants held an Olympic plate-loaded dumbbell vertically (08) by the handle in 1 hand. The vertical line formed by the second flexed knuckles (second proximal interphalangeal joints) surrounding the dumbbell was at 08. After
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supinating to the participants’ full ROM (80–1008), the participants pronated the dumbbell to the starting vertical (08) position for the repetition to be recorded. Participants followed the same procedures as the forearm supination 10RM test. Wrist Radial Deviation
Each participant’s D hand was tested first. The participant’s arm and shoulder were placed in the neoprene sleeve and tightly secured to his torso with his shoulder adducted, wrist medially rotated, and elbow fully extended at 1808. Next, the first of 2 neoprene bands was wrapped and secured around the upper arm and opposite side of the upper torso. The other band was wrapped and secured around the lower arm (just below the elbow) and opposite side of the hip so the participant’s entire arm was held tightly to his side. This isolated the use of the flexor carpi radialis, extensor carpi radialis longus, and extensor carpi radialis brevis. To measure each participant’s full ROM, a goniometer was lined up over the ulnar styloid process (blunt, bony end of the lateral wrist) parallel to the third extended metacarpal (08) and the angle (40–608) formed by each participant’s radial deviated wrist at the third extended metacarpal. The participants held an Olympic plate-loaded dumbbell below the bottom collar in 1 hand with the dumbbell pointing in front of them. Then, the goniometer was lined up over the ulnar styloid process and the parallel third knuckle (interphalangeal joint) of the third metacarpal surrounding the dumbbell (08). The participants were instructed to raise (radial deviate) the dumbbell to the previously recorded angle formed without the dumbbell for the repetition to be recorded. Participants followed the same procedures as the forearm supination 10RM test. Wrist Ulnar Deviation
Each participant’s D hand was measured first. The same procedures for securing the participant’s arm used for wrist radial deviation were followed. When performing the ulnar deviation, these procedures isolated the use of the flexor carpi radialis, extensor carpi radialis longus, and extensor carpi radialis brevis. To measure each participant’s full ROM, a goniometer was lined up over the radial styloid process (blunt, bony end of the medial wrist) parallel to the third extended metacarpal (08) and the angle (20–408) formed by each participant’s ulnar deviated wrist at the third extended metacarpal. The participants held an Olympic plate-loaded dumbbell above the bottom collar in 1 hand with the dumbbell pointing behind them. Then, the goniometer was lined over the radial styloid process and the parallel third knuckle (interphalangeal joint) of the third metacarpal surrounding the dumbbell (08). The participants were instructed to raise (ulnar deviate) the dumbbell to the previously recorded angle formed without the dumbbell for the repetition to be recorded. Participants followed the same procedures as the forearm supination 10RM test. Grip Strength
A Jamar Hydraulic Hand Dynamometer (Sammons Preston, Bolingbrook, IL), set at the second handle position for all participants, was used to assess grip strength for both hands (D and ND) because it is the most accurate
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measure of grip strength (14). Grip strength was assessed at 0 and after 12 weeks of training. For each of the grip strength tests, each participant was seated in a standard chair (46-cm high) without an arm rest with his shoulder adducted and neutrally rotated, elbow flexed at 908, and forearm and wrist in a neutral position (14). The investigator allowed the participants to use a wrist position between 0 and 308 extension and between 0 and 158 ulnar deviation according to previous research by Mathiowetz et al. (14) and Stanley and Tribuzi (19). Participants followed the protocol described by Mathiowetz et al. (14). For each grip strength test, the scores of 3 successive trials with 1-minute rest between trials were recorded and averaged for each hand, beginning with the D hand (12, 14, 19). The dynamometer was lightly held around the readout dial to prevent inadvertent dropping (14, 19). Standardized instructions described by Mathiowetz et al. (14) were used. The calibration of the Jamar dynamometer was tested with a Jamar Calibration Station (Lafayette Instrument Co., Lafayette, IN) before pre- and posttesting. This calibration station consisted of slotted weights certified by the National Institute of Standards and Technology, a weight stand, and a fixture to hang the weights. Muscular Strength: PS and BP
According to Baechle et al. (2), many of the participants in this study were classified as a beginner or intermediate lifter (,1 year of resistance-training experience). Because of this training status, an estimation of 1RM (the most amount of weight lifted one time) was determined by performing 3RM tests (the most amount of weight lifted 3 times) on the PS and BP with Olympic-standard free weights because it was safer (23). Furthermore, 3RM tests were used because the participants may not have been accustomed to handling heavy loads and may have had a fear of failing or getting injured (16). A regimen of full-body stretching exercises was performed before all testing sessions. Three minutes of rest were between near-maximal lifts (6). The 1RM was estimated by using the Load Assessment Table adapted from Wathen (24). The 3RM for PS and BP was assessed to estimate 1RM at 0 and after 4, 8 (to ensure that appropriate percentages were used during training), and 12 weeks of training by using the methods described by Earle and Baechle (6). The 3RM was determined to be the maximal weight lifted after 2 consecutive unsuccessful trials (18). The progression of incremental load increases used for both tests had already been established for 1RM testing (2). Weight belts were worn during nearmaximal lifts. Proper spotting techniques were demonstrated and used for all exercises (6). The lead author used a Weight Training Percentages Table (24) to determine the appropriate resistance (%) of the predicted 1RM for PS and BP during each training session. Statistical Analyses
Independent sample t-tests were conducted before the 12week study to determine if any significant differences existed between the 2 groups. To determine if any differences existed between or within groups, repeated measures analyses of variance were conducted on all variables. The alpha level was set at p # 0.05. All data are presented as group means (6SD).
Table 5. Mean (6SD) 10RM wrist barbell flexion, wrist barbell extension, D and ND hand-forearm pronation, forearm supination, wrist radial deviation, and wrist ulnar deviation for pre- and posttest and percent (%) change.†Variable
Pretest
Posttest
% Change
Wrist barbell flexion, kg Group 1 Group 2
34.8 (5.9) 39.1 (6.5) 11.0%* 33.8 (4.2) 46.3 (8.8) 27.0%*,***
Wrist barbell extension, kg Group 1 Group 2
12.2 (3.0) 14.6 (2.7) 16.4%* 12.7 (2.5) 16.8 (2.7) 24.4%*,***
D forearm pronation, kg Group 1 Group 2
12.0 (1.5) 12.6 (1.2) 4.8%* 12.4 (1.6) 14.1 (1.5) 12.0%*,***
ND forearm pronation, kg Group 1 Group 2
11.2 (1.4) 12.1 (1.2) 7.4%* 12.1 (1.4) 13.6 (1.4) 11.0%*,***
D forearm supination, kg Group 1 Group 2
10.9 (1.5) 11.2 (1.7) 11.1 (1.3) 11.9 (1.3)
2.7% 7.5%**,***
ND forearm supination, kg Group 1 Group 2
10.5 (1.2) 10.9 (1.4) 10.8 (1.5) 11.6 (1.4)
3.7% 8.5%**,***
D wrist radial deviation, kg Group 1 Group 2
9.6 (1.0) 11.9 (1.0) 19.3%* 9.5 (1.5) 13.0 (1.0) 26.9%*,***
ND wrist radial deviation, kg Group 1 9.9 (1.0) 11.8 (1.0) 16.1%* Group 2 9.4 (1.4) 13.0 (1.0) 27.7%*,*** D wrist ulnar deviation, kg Group 1 Group 2
10.6 (1.2) 14.1 (2.4) 24.8%* 10.9 (1.8) 16.0 (1.5) 31.9%*,***
ND wrist ulnar deviation, kg Group 1 10.6 (1.1) 13.7 (1.9) 22.6%* Group 2 10.7 (1.6) 15.9 (1.2) 32.7%*,*** * Significant difference within groups at p , 0.01. †RM 5 repetition maximum; D 5 dominant; ND 5 nondominant. ** Significant difference between groups at p , 0.05. *** Significant differences within groups at p , 0.05.
RESULTS Dynamic Wrist and Forearm Strength
We determined from the pretreatment independent sample t-tests that no differences were between the 2 groups for 10RM wrist barbell flexion, wrist barbell extension, D and ND forearm pronation, forearm supination, wrist radial deviation, and wrist ulnar deviation. Pretreatment mean (6SD) for all wrist and forearm strength measures for both groups are presented in Table 5. Posttreatment mean (6SD) and percent change for all wrist and forearm strength measures for group 1 and group 2 are presented in Table 5. Both groups showed significant increases in all wrist and forearm strength measurements except 10RM D and ND forearm supination for group 1. Group 2 showed statistically greater improvements in all wrist and forearm strength variables (kg 6 SD).
WRIST Table 6. Mean (6SD) D and ND grip strength for pre- and posttest and percent (%) change.† Pretest
Posttest
% Change
D grip strength, kg Group 1 Group 2
Variable
50.3 (9.0) 52.1 (6.3)
53.4 (9.2) 55.3 (6.3)
5.7%* 5.7%*
ND grip strength, kg Group 1 Group 2
48.7 (7.9) 50.3 (7.2)
51.4 (8.7) 52.1 (6.7)
5.1%* 3.5%*
* Significant difference within groups at p , 0.05. † D 5 dominant; ND 5 nondominant.
Table 7. Mean (6SD) predicted 1RM PS and BP at 0 and after 4, 8, and 12 weeks of training and percent (%) change.† Variable PS, kg Group 1 Group 2
0 Wks
8 Wks
12 Wks
97.5 (19.3) 117.8 (24.2) 133.4 (24.1) 147.1 (24.9) 99.4 (25.5) 114.6 (24.7) 131.6 (24.7) 143.5 (25.8)
% Change Group 1 Group 2 BP, kg Group 1 Group 2
4 Wks
71.8 (16.3) 72.9 (15.4)
% Change Group 1 Group 2
17.2%* 13.2%*
26.9%** 24.5%**
33.7%*** 30.7%***
78.2 (15.3) 79.8 (16.8)
83.7 (15.3) 83.9 (15.9)
86.9 (15.4) 86.8 (14.2)
14.2%** 13.5%**
17.4%*** 15.9%***
8.2%* 8.7%*
* Significant difference within groups after 4 weeks of training at p , 0.05. † RM 5 repetition maximum; PS 5 parallel squat; BP 5 bench press. ** Significant difference within groups after 8 weeks of training at p , 0.05. *** Significant difference within groups after 12 weeks of training at p , 0.05.
Grip Strength
We determined from the pretreatment independent sample t-tests that no differences were between the 2 groups for D and ND grip strength. Pretreatment mean (6SD) for D and ND grip strength for group 1 and group 2 are presented in Table 6. Posttreatment mean (6SD) and percent change after 12 weeks of training for D and ND grip strength for group 1 and group 2 are presented in Table 6. Both groups showed significant increases in D and ND grip strength (kg 6 SD) after 12 weeks of training; however, no significant differences were between groups. Muscular Strength: PS and BP
We determined from the pretreatment independent sample t-tests that no differences were between the 2 groups for predicted 1RM (kilogram) PS and BP. Pretreatment mean (6SD), listed under 0 weeks, for predicted 1RM PS and BP for group 1 and group 2 are presented in Table 7. Mean (6SD) and percent change after 4 weeks of training for predicted 1RM (kilogram) PS and BP for group 1 and group 2 are presented in Table 7. Both groups showed significant increases in predicted 1RM PS
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and BP after 4 weeks of training; however, no differences were between groups. Mean (6SD) and percent change after 8 weeks of training for predicted 1RM (kilogram) PS and BP for group 1 and group 2 are presented in Table 7. Both groups showed significant increases in predicted 1RM PS and BP after 8 weeks of training; however, no differences were between groups. Posttreatment mean (6SD) and percent change after 12 weeks of training for predicted 1RM (kilogram) PS and BP for group 1 and group 2 are presented in Table 7. Both groups showed significant increases in predicted 1RM PS and BP after 12 weeks of training; however, no differences were between groups.
DISCUSSION To our knowledge, no other study has evaluated the effect of 12 weeks of wrist and forearm training on high school baseball players or any other participants. Previous baseball-related research has been designed to investigate the effect of different strength-training protocols on bat swing or throwing velocity. Because baseball coaches believe that wrist and forearm strength are integral components of baseball performance, especially for successful hitting, it is a wonder why this topic has not been previously examined. The amount of sets and repetitions in this study for wrist and forearm exercises was determined by strength research on other topics (4, 22) and personal experience. The degree of improvement in wrist and forearm strength for group 1 in the current study was surprising. Even though group 1 did not perform any specific wrist or forearm exercises, they significantly increased wrist and forearm strength for all but 2 strength measures. Group 2, as expected, made statistically greater increases in all wrist and forearm strength measures. Because there is not any previous research relevant to specific wrist and forearm training, unpublished work by Dulchinos (5), which evaluated the relationship of wrist strength to bat-swing velocity of male college baseball players, will be compared. The treatment group performed 3 sets of 10 repetitions for wrist flexion and extension 3 days per week for 5 weeks. However, only wrist adduction, which is also known as wrist ulnar deviation, of the strongest hand by using a tensiometer was measured pre- and posttraining. One of the flaws with Dulchinos’s study (5) was that wrist flexion and extension were performed for 5 weeks, but wrist adduction was omitted. If wrist adduction were used as an evaluated strength measure, then it should have been performed as an exercise during the study. However, this was not the case. Another flaw in Dulchinos’s study (5) was that only wrist adduction of the strongest hand was reported. Holding a bat and hitting a baseball requires the use of both hands. The contribution of each hand to bat velocity is unknown. Therefore, the adduction strength of both wrists should have been evaluated and reported. According to Dulchinos (5), the control group had no improvement (0.0%) in wrist adduction strength for either hand. The treatment group had a 17.8% increase of wrist adduction strength of the strongest hand. In comparison, in the current study group 1 increased D and ND wrist ulnar deviation 24.8 % and 22.6 %, respectively. Group 2 increased D and ND ulnar deviation 31.9% and 32.7%, respectively. The D and ND ulnar deviation strength im-
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provements for group 1 in the present study were larger than the wrist adduction results of the control group in the study by Dulchinos (5), who did not perform any resistance exercises. Group 1 in the current study held on to barbells while performing weight-training exercises 3 days a week for 12 weeks. This produced a training effect that allowed wrist and forearm strength improvements. The D and ND ulnar deviation strength improvements for group 2 in the present study were greater than the wrist adduction strength improvements of the treatment group in the study by Dulchinos (5), who did not perform wrist adduction exercises during the 5-week training sessions. The larger increases in D and ND ulnar deviation strength, as well as all other wrist and forearm strength measures for group 2 in the current study, occurred because of the specific training of those movements over 12 weeks. The degrees of improvement in grip strength for both groups in the current study were similar. Group 1, who did not perform any grip strength exercises, performed as well as group 2. However, the standing plate-squeeze exercise, which was chosen to develop grip strength, was a limited exercise. In particular, the 20-kg Olympic plates used by the participants did not have large rims around the edge of the plates. Thus, the grip and the ability to perform the exercise through a full ROM were limited. Therefore, the results for group 2 compared with group 1 were not surprising. In a related study, Giardina et al. (7) evaluated the relationship of grip strength and forearm size to bat velocity in female college softball players. The mean (6SD) grip strength of the left hand was 38.1 (5.5) kg and the right hand was 41.0 (4.5) kg. According to Mathiowetz et al. (13) the mean grip strength for untrained women 20– 24 years old was 61.0 lb (27.7 kg) for the left hand and 70.4 lb (31.9 kg) for the right hand. The mean grip strength for the female softball players (mean age 5 20.3 years) in the study by Giardina et al. (7) was greater. A possible explanation for the greater grip strength could be that the softball players were stronger than the women in the study by Mathiowetz et al. (13) because they were athletes. The female college softball players did have a minimum of 5-years playing experience and may have had weight-training experience. Thus, grip strength could have been developed from holding and gripping the softball bat while swinging and from holding on to barbell or dumbbells. In the current study, the mean (6SD) pretraining D grip strength for male high school baseball players was 50.3 (9.0) kg for group 1 and 52.1 (6.3) kg for group 2. The mean (6SD) pretraining ND grip strength for male high school baseball players was 48.7 (7.9) kg for group 1 and 50.3 (7.2) kg group 2. According to Mathiowetz et al. (15), the mean grip strength for boys 14–15 years old was 64.4 lb (29.2 kg) for the left hand and 77.3 lb (35.0 kg) for the right hand. Mean grip strength for boys 16–17 years old was 78.5 lb (35.6 kg) for the left hand and 94.0 lb (42.6 kg) for the right hand. The mean pretraining grip strength for the male high school baseball players (mean age 5 15.3 6 1.1 years) in the current study were greater than the means produced in the study by Mathiowetz et al. (15). The explanation for the greater grip strength is similar to the reasoning for the increase in the female softball players’ grip strength. The male high school baseball players in the current study did have previous play-
ing and weight-training experience before they engaged in the research project. This would have most likely made their pretraining grip strength stronger than the average untrained boy of a similar age. The degrees of improvement in predicted 1RM PS and BP in the present study are similar to the results found by other researchers (4, 26) using similar training programs. In the present study, predicted 1RM for group 1 improved over 12 weeks of training 30.7% for PS and 15.9% for BP and for group 2 33.7% for PS and 17.4% for BP. Participants who performed a 12-week linear periodized program, which is now described as stepwise, in the study by Baker et al. (4) improved 27.7 and 11.6% in PS and BP. Baker et al. (4) used participants with at least 6 months of weight-training experience. According to the classifications used in the current study, these participants would be described as intermediate lifters, which was similar to the participants in the current study. However, Baker et al. (4) used college-aged participants who had greater initial PS and BP strength. Thus, the larger gains in PS and BP for participants in the current study would be expected because they were not as physically mature or initially as strong as the ones in Baker et al. (4). Willoughby (26) indicated that previously weighttrained participants increased 1RM PS and BP 34.0 and 23.0% after performing a linear periodized program. Participants were considered trained if their 1RM PS and BP were equal to or greater than 150 and 120% of total body weight. Participants performed PS and BP exercises 3 days per week for 16 weeks. In the current study, pretraining-predicted 1RM PS exercises were 135% of total body weight for group 1 and 138% of total body weight for group 2. The pretraining-predicted 1RM BP exercises were 99% of total body weight for group 1 and 101% of total body weight for group 2. Therefore, participants in the current study would not have been described as previously trained because they were not as strong as the participants used by Willoughby (26). Participants in the current study performed PS exercises 2 days per week and BP exercises 3 days per week. Additionally, these participants performed either 4 or 5 assistance exercises (see Table 4). Therefore, there was a larger total training volume (mass lifted) performed compared with the program designed by Willoughby (26). The low total-training volume completed by participants in the study by Willoughby (26) should have contributed, in part, to the large gains in PS and BP exercises because they did not perform any assistance exercises. Furthermore, the strength gains could also be expected because the participants trained for 4 additional weeks. In contrast to research cited above, Willoughby (25), in a similar training program, indicated that trained college-aged participants increased 1RM PS and BP exercises 48.0 and 28.0% after performing a linear periodized program. Training status of participants was identical to the other study by Willoughby (26). Participants performed PS and BP exercises 2 days per week for 12 weeks. The results indicated that performing PS and BP exercises 2 days per week produced significantly greater strength gains than did training 3 times per week with trained college-aged individuals for 16 weeks in the study by Willoughby (26) and high school baseball players for 12 weeks in the current study. These results suggest that greater strength improvements in PS and BP exercises
WRIST
can be accomplished, in part, by training with a lower total-training volume and frequency for both trained college-aged individuals and high school baseball players. Participants who performed a 12-week stepwise program in Stone et al. (22), similar to previous research (4, 25, 26), reported significant strength gains in PS exercises but not to the degree as with other research (4, 25, 26). Participants were college-aged male volunteers who met the following criteria: initial 1RM PS exercises greater than 110 kg and greater than 1.3 times body mass and the ability to complete at least 80% of the programmed repetitions. These criteria were similar to the 2 studies by Willoughby (25, 26). The participants in the current study had initial-predicted 1RM PS exercises of 97.5 kg for group 1 and 99.4 kg for group 2. Because of the lower initial-predicted 1RM PS values, the individuals in the current study would not have been participants in the study by Stone et al. (22). The results indicated that the stepwise program increased 1RM PS exercises 13.0% after 12 weeks of training. As expected, the PS strength gains (.30%) for the participants in the current study were greater than for the participants in Stone et al. (22) because of maturation status, a lack of previous weighttraining experience, and lower initial PS strength. The large percent improvements in predicted 1RM PS exercises achieved in the current study are not often seen in well-trained participants as a result of heavy strength training (3, 20). According to Hakkinen et al. (9), highly trained athletes who have a higher pretraining status will have limited absolute strength gains. Thus, the extent of strength gains will be, in part, defined by the amount of adaptations that have already occurred from previous training (10). In the current study, the significant initial strength gains made during the first 4–8 weeks of training (see Table 7) are primarily attributed to neural adaptations marked by an increase in integrated electromyographic (IEMG) activity, an increased rate of motor unit activity, and increased motor unit synchronization (17). As training continued from 8 to 12 weeks, research (8) has shown that IEMG activity begins to level off or even decrease, which may be a result of an increase in the cross-sectional area of muscle (hypertrophy) of both type I (slow twitch) and type II (fast twitch) fibers and, subsequently, an increase in the rate of force production by the muscle. The effect of wrist and forearm training on wrist and forearm strength for collegiate and professional baseball players or other athletes is unknown. Thus, more research needs to be conducted to clarify whether wrist and forearm training will produce similar results with players of different maturation status or sport. Additionally, research evaluating the effect of wrist and forearm strength on bat-swing velocity and time to ball contact should be studied. This will allow coaches to determine the value of the exercises used in their training programs.
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may not need to focus as much attention on specific wrist and forearm training because wrist and forearm strength are increased by performing resistance-training exercises. However, if 2 of the goals of the resistance-training program are to maximize wrist and forearm strength while maintaining a low risk of injury for athletes who play sports that require holding implements such as baseball or softball, golf, gymnastics, racquet sports, rowing, and rock climbing or throwing implements such as a baseball or softball, javelin, discus, and shot put, then the sets and repetitions used in this study for wrist and forearm exercises should be added to the athletes’ exercise program.
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PRACTICAL APPLICATIONS If the amount of time spent in the weight room is limited for an athlete because of class schedule, practice time, or playing in games, a coach may elect to focus their players’ resistance-training program on core exercises, such as PS, BP, and bent-over rows in a periodized program. Although baseball coaches believe that strong wrists and forearms are essential to good hitting, the results of the present study indicate that high school baseball players
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TAN, B. Manipulating resistance training program variables to optimize maximum strength in men: A review. J. Strength Cond. Res. 13:289–304. 1999. WATHEN, D. Load assessment. In: Essentials of Strength and Conditioning. T.R. Baechle, ed. Champaign, IL: Human Kinetics, 1994. pp. 435–439. WILLOUGHBY, D.S. A comparison of three selected weight training programs on the upper and lower body strength of trained males. Ann. J. Appl. Res. Coaching Athletics. March:124–146. 1992. WILLOUGHBY, D.S. The effects of meso-cycle-length weight training programs involving periodization and partially equated volumes on upper and lower body strength. J. Strength Cond. Res. 7:2–8. 1993.
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