SHOULDER STRENGTH IN THE FEMALE THROWING ATHLETE

Abstract

Although a considerable amount of research has been published regarding the strength profile of baseball players, few have looked specifically at the shoulder rotational strength of female athletes. The purpose of this study was to investigate the effects of position and speed on shoulder rotational strength in female throwing athletes and normal controls. Twenty-four volunteers were placed into two categories: 1) division I intercollegiate softball players (N = 14), or 2) non-throwing, recreationally active females (N = 10). Shoulder internal (IR) and external rotation (ER) strength were measured isokinetically at 90, 180, 300°/s, with the subjects seated in both a modified neutral position (30° abduction), and in a position of 90° abduction and 90° elbow flexion (90°–90°). Peak torque, average power and ER/IR ratios were recorded. Throwing athletes had 19% higher ER power (p = 0.05) and 18% higher ER/IR power ratio (p = 0.006) than controls. The greater ER power in throwing athletes was most prominent at 300°/s (25%). Additionally, throwing athletes demonstrated greater ER average power in the 90–90 at 300°/s only (IR p = 0.019; ER p = 0.001), with a similar effect between throwing athletes and controls. IR peak torque increased with increasing velocity (p < 0.001), while ER peak torque was unaffected. The difference in average ER power between female throwing athletes and controls may be attributed to fatigue resistance secondary to repetitive deceleration of the arm during the throwing motion. Between group differences were similar in the neutral and 90–90 positions, despite the fact that the 90–90 position is thought to be more functional for the throwing athlete. In conclusion, the data acquired during this study demonstrate the importance of high speed isokinetic testing in the female throwing athlete.