Abstract

Joint angle kinematics of the throwing limb from the early-cocking phase to ball release were investigated for the fastball (FB) and curveball (CB) baseball pitches through use of a three-dimensional film analysis technique. Small sticks were fixed to the hand and forearm to permit rotations of the radioulnar and wrist joint to be calculated. The actions were very similar for two pitches within one subjects. There were no differences in the motions of the shoulder and elbow joints or in the temporal sequences between FB and CB pitches. However, there was a significant difference (p<0.05) in the motion of supination/pronation of the forearm and dorsiflexion/palmar flexion of the wrist prior to the ball release; the forearm was supinated more in the CB (maximum supination: 39.9+/-6.0 degrees at 0.072+/-0.045 s before ball release, or BRL) compared to the FB (19.4+/-8.5 degrees at 0.076+/-0.046 s before BRL), whereas the wrist was dorsiflexed more in the FB (maximum dorsiflexion: 41.7+/-6.5 degrees at 0.039+/-0.11 s before BRL) compared to the CB (31.2+/-4.7 degrees at 0.036+/-0.013 s before BRL) during late-cocking and acceleration phases leading to the ball release. Verf.-Referat