INFLUENCE OF SPORTS DISCIPLINE ON SHOULDER ROTATOR CUFF BALANCE

Isokinetic shoulder rotational strength was evaluated in four groups o f subjects as follows: 12 nonathletes, 12 runners, 15 tennis players, and 12 baseball players for a total of 51 subjects. The tests were per formed in the seated 45 degrees abducted test position in the scapular plane at 60, 180, and 300 degrees.s(-1) for both shoulders. Peak torq ue and mean power values were gathered, and from these values the inte rnal/external rotation ratios were calculated. Intergroup comparison s howed a progression of the ratio related to the sports discipline. The nonathletes and runners had ratios close to those reported for nonath letes (1.3 to 1.5). The tennis players had ratios close to 1.5, wherea s the baseball players had ratios from 1.6 to 2.2. The comparison betw een dominant and nondominant side showed no significant differences in the tennis players and higher values for the dominant side in the non athletes and runners under certain conditions (180 degrees.s(-1) for t he nonathletes and 300 degrees.s(-1) for the runners). Regarding the b aseball players, the ratio was systematically higher for the dominant side. These results raise questions about the influence of sports disc ipline on the internal/external rotator muscle ratio and indicate the need to establish normative values based on the characteristics of the population under study.