Differences of joint movements between the shoulder and the elbow used in fastball/curveball pitches: a dynamic analysis

Summary form only given. A baseball pitcher's shoulder joint is undoubtedly the most vulnerable part of his/her body. To gain a better understanding of its motion, and the stresses placed on it during strenuous activities, such as baseball pitching, we measured its action, using a state-of-the-art CCD camera system. Limitations in the previous system made accurate, high-speed measurements of pitching motion, and estimating all moments of the elbow/shoulder joint difficult. The new motion capture system we employ measures pitching motion using 34 markers, at 500 Hz. The shoulder/elbow joint's moment was estimated from a series of fastball and curveball pitches. Significant differences were noted, between the two pitches, for instance, the pronation moment of the elbow joint, when a ball is released.