Journal of Orthopaedic & Sports Physical Therapy - E. Paul Roetert, PhD, FACSM

Report Testing Isokinetic Muscular Fatigue of Shoulder Internal and External Rotation in Elite Junior Tennis Players

Todd S. Ellenbecker, E. Paul Roetert
Study Design: Single group, posttest only descriptive analysis of isokinetically measured shoulder internal and external rotation muscular fatigue. Objectives: To determine whether differences in isokinetically measured muscular fatigue exist between shoulder external (ER) and internal rotation (IR) and between the dominant (DOM) and nondominant (NDOM) extremity in elite junior tennis players. Background: The importance of the rotator cuff in stabilizing the humeral head during repetitive athletic overhead motions has been identified in biomechanical investigations. The application of exercise to improve muscular function of the shoulder and prevent injury is a common practice in physical therapy, but shoulder fatigue in tennis players has received little attention in the literature. Methods and Measures: Seventy-two elite junior tennis players (ages 12 to 18) underwent bilateral isokinetic testing with 90� of glenohumeral joint abduction. A muscular fatigue protocol consisting of 20 maximal-effort concentric contractions of ER and IR was used to measure muscular fatigue at 300�/s. A relative fatigue ratio was calculated by dividing the work in the last 10 repetitions by the work in the first 10 repetitions. Higher fatigue ratios indicate improved muscular fatigue resistance. A 2 x 2 ANOVA was used to assess differences in fatigue in DOM versus NDOM arm, and in IR versus ER. Results: Relative muscular fatigue ratios for ER and IR were 69.1 � 15.3% and 82.93 � 14.81% for the DOM extremity, respectively. In the NDOM extremity, ER and IR fatigue ratios were 71.13 � 15.07% and 83.9 � 16.5%, respectively. These results indicate significant differences between the fatigue ratios for ER and IR. No significant difference between extremities in either ER or IR relative fatigue ratios was found. Conclusions: These data have implications for rehabilitation and conditioning of the rotator cuff musculature. J Orthop Sports Phys Ther. 1999;29(5):275-281. Key Words: shoulder, muscular fatigue, tennis

Glenohumeral Joint Internal and External Rotation Range of Motion in Elite Junior Tennis Players

Todd S. Ellenbecker, E. Paul Roetert, Patty A. Piorkowski, David A. Schulz

Objective measurement of range of motion of the glenohumeral joint is important for the rehabilitation and prevention of shoulder injury. The primary purpose of this study was to determine whether significant differences exist between the dominant (tennis playing) and nondominant extremity in active internal and external rotation range of motion in elite junior tennis players 11-17 years of age. Two hundred three elite junior tennis players (113 males, 90 females) were bilaterally measured for internal and external rotation at 90° of abduction in a supine position with a specific methodology attempting to isolate glenohumeral motion, while minimizing or negating scapulothoracic motion. A standard universal goniometer was utilized to measure active range of motion (AROM). Dependent t tests were used to compare differences between extremities. No significant difference was found for males or females between the dominant and nondominant arm in external rotation. Analysis of internal rotation (AROM) differences showed significantly less (p < .001) internal rotation (AROM) on the dominant arm for both males and females. Significantly less (p < .001) dominant arm total rotational range of motion was also found in both males and females. The loss of dominant arm internal rotation (AROM) has clinical application for both the development of rehabilitation and preventative flexibility/range of motion programs.

J Orthop Sports Phys Ther. 1996;24(6):336-341.

Key Words: shoulder, joint motion, tennis

Isokinetic Profile of Elbow Flexion and Extension Strength in Elite Junior Tennis Players

Todd S. Ellenbecker, E. Paul Roetert
Study Design: Descriptive study. Objectives: To determine whether bilateral differences exist in concentric elbow flexion and extension strength in elite junior tennis players. Background: The repetitive nature of tennis frequently produces upper extremity overuse injuries. Prior research has identified tennis-specific strength adaptation in the dominant shoulder and distal upper extremity musculature of elite players. No previous study has addressed elbow flexion and extension strength. Methods and Materials: Thirty-eight elite junior tennis players were bilaterally tested for concentric elbow flexion and extension muscle performance on a Cybex 6000 isokinetic dynamometer at 90°/s, 210°/s, and 300°/s. Repeated measures ANOVAs were used to test for differences between extremities, muscle groups, and speed. Results: Significantly greater (P<0.002) dominant-arm elbow extension peak torque values were measured at 90°/s, 210°/s, and 300°/s for males. Significantly greater (P<0.002) dominant-arm single-repetition work values were also measured at 90°/s, 210°/s, and 300°/s for males. No significant difference was measured between extremities in elbow flexion muscular performance in males and for elbow flexion or extension peak torque and single-repetition work values in females. No significant difference between extremities was measured in elbow flexion/extension strength ratios in females and significant differences between extremities in this ratio were only present at 210°/s in males (P<0.002). Conclusion: These data indicate muscular adaptations around the dominant elbow in male elite junior tennis players but not females. These data have ramifications for clinicians rehabilitating upper extremity injuries in patients from this population.

J Orthop Sports Phys Ther, 2003;33(2):79-84.

Key Words: muscular strength, sports, upper extremity