RESUMO
BACKGROUND: Plyometric exercises are frequently used to increase posterior rotator cuff and periscapular muscle strength and simulate demands and positional stresses in overhead athletes. The purpose of this study was to provide descriptive data on posterior rotator cuff and scapular muscle activation during upper extremity plyometric exercises in 90° of glenohumeral joint abduction. HYPOTHESIS: Levels of muscular activity in the posterior rotator cuff and scapular stabilizers will be high during plyometric shoulder exercises similar to previously reported electromyographic (EMG) levels of shoulder rehabilitation exercises. STUDY DESIGN: Descriptive laboratory study. METHODS: Twenty healthy subjects were tested using surface EMG during the performance of 2 plyometric shoulder exercises: prone external rotation (PERP) and reverse catch external rotation (RCP) using a handheld medicine ball. Electrode application included the upper and lower trapezius (UT and LT, respectively), serratus anterior (SA), infraspinatus (IN), and the middle and posterior deltoid (MD and PD, respectively) muscles. A 10-second interval of repetitive plyometric exercise (PERP) and 3 repetitions of RCP were sampled. Peak and average normalized EMG data were generated. RESULTS: Normalized peak and average IN activity ranged between 73% and 102% and between 28% and 52% during the plyometric exercises, respectively, with peak and average LT activity measured between 79% and 131% and between 31% and 61%. SA activity ranged between 76% and 86% for peak and between 35% and 37% for average activity. Muscular activity levels in the MD and PD ranged between 49% and 72% and between 12% and 33% for peak and average, respectively. CONCLUSION: Moderate to high levels of muscular activity were measured in the rotator cuff and scapular stabilizers during these plyometric exercises with the glenohumeral joint abducted 90°.
RESUMO
OBJECTIVES: To measure short-term post surgery glenohumeral internal and external rotation strength, shoulder range of motion (ROM), and subjective self-report ratings following arthroscopic superior labral (SLAP) repair. BACKGROUND: Physical therapists provide rehabilitation for patients following arthroscopic repair of the superior labrum. Little research has been published regarding the short-term results of this procedure while the patient is typically under the direct care of the physical therapist. METHODS: Charts from 39 patients (7 females and 32 males) with a mean age of 43.4±14.9 years following SLAP repair were reviewed. All patients underwent rehabilitation by the same therapist using a standardized protocol and were operated on and referred by the same orthopaedic surgeon. Retrospective chart review was performed to obtain descriptive profiles of shoulder ROM at 6 and 12 weeks post surgery and isokinetically documented internal and external rotation strength 12 weeks post surgery. RESULTS: At 12 weeks post-surgery, involved shoulder flexion, abduction, and external rotation active ROM values were 2-6 degrees greater than the contralateral, non-involved extremity. Isokinetic internal and external rotation strength deficits of 7-11% were found as compared to the uninjured extremity. Patients completed the self-report section of the Modified American Shoulder Elbow Surgeons Rating Scale and scored a mean of 37/45 points. CONCLUSION: The results of this study provide objective data for both glenohumeral joint ROM and rotator cuff strength following superior labral repair at time points during which the patient is under the direct care of the physical therapist. These results show a nearly complete return of active ROM and muscular strength following repair of the superior labrum and post-operative physical therapy.
RESUMO
BACKGROUND: Tennis requires repetitive multidirectional movement patterns that can lead to lower extremity injury. Knowledge of population and age-specific strength parameters can be used during performance enhancement training and rehabilitation of tennis players. OBJECTIVES: The purpose of this study was to generate population and age-specific descriptive profiles of concentric isokinetic knee extension and flexion strength in elite junior tennis players, and determine whether bilateral differences exist between extremities and across age ranges. METHODS: A total of 103 elite male tennis players (mean (SD) 15.92 (2.14), range 11-21) and 53 female tennis players (mean (SD) 15.0 (2.30, range 11-21) were isokinetically tested on a Cybex 6000 isokinetic dynamometer at 180 and 300 degrees/s to assess bilateral concentric knee extension and flexion strength using a standard bilateral testing protocol. RESULTS: No significant bilateral difference between the dominant (racquet side) lower extremity and the contralateral non-dominant side were measured in lower extremity knee extension or flexion strength normalised to body weight, or in the hamstring quadriceps strength ratios in male and female subjects. Male subjects did show significant (p<0.001) increases in knee extension and flexion strength across the age ranges from 11-15 years of age to 16-21 years. Female subjects did not show any significant change in the normalised knee extension or flexion strength across age ranges. Hamstring/quadriceps strength ratios were bilaterally symmetric and remained clinically and statistically constant across age ranges for the male and female elite tennis players. CONCLUSIONS: Population and age-specific isokinetic descriptive data from elite tennis players can provide guidance in the development and monitoring of performance enhancement and rehabilitation programs for elite tennis players. The changes identified in normalised knee extension and flexion strength in elite male tennis players necessitate the use of population and age-specific descriptive data.
