Affiliations: [a] HEALTHSOUTH SportsMedicine and Rehab of Scottsdale
Note: [*] Address reprint requests to Todd S. Ellenbecker, MS, PT, HEALTHSOUTH SportsMedicine and Rehab of Scottsdale, 5111 N. Scottsdale Road, Suite 100, Scottsdale, AZ 85250
Abstract: The purpose of this study was to determine whether significant strength differences exist between the dominant and nondominant arms of highly skilled tennis players. The relationship of this strength to the speed of a maximal effort tennis serve was also studied. Isokinetic testing of 22 highly skilled male tennis players was done using a Cybex II dynamometer and a Discipline RTD computerized data reduction system. Tests were conducted bilaterally for shoulder internal/external rotation, flexion/extension, forearm pronation/supination, and wrist flexion/extension. Speeds of 90, 210, and 300 deg/sec were used. Initial postimpact ball velocity of 15 maximal tennis serves was measured by a CMI radar gun and RCA video camera. Significantly greater (p < .005) isokinetic strength was found in the dominant arm for shoulder internal rotation and flexion, as well as wrist flexion and forearm pronation. Shoulder extension and wrist extension were also stronger (p < .001) on the dominant arm. No differences were found between extremities for shoulder external rotation and forearm supination. Mean postimpact ball velocity measured by a radar gun was 107.8 ± 6.3 miles per hour and did not significantly correlate with any pattern of isokinetically measured strength. Postimpact ball velocity measured by video digitizing was 117.3 ± 10.4 miles per hour. Results from this investigation show greater dominant arm isokinetic muscular strength, as well as specific ratios of muscle strength surrounding joints of the upper extremity. These strength data did not correlate with the speed of a maximal effort tennis serve. These data are important for design of muscle conditioning and rehabilitation programs for athletes in unilaterally dominant upper extremity sports.
