INFLUENCE OF LATERAL TRUNK TILT ON THROWING ARM KINETICS DURING BASEBALL PITCHING

Abstract

The purpose of this study was to investigate the relationship between lateral trunk tilt angle and several injury-related kinetic parameters during pitching. Based on kinematic data of 12 overhand and three-quarter-hand pitchers, several pitching motions with different lateral trunk tilt angles from the original were simulated. Joint kinetics among the simulated motions was compared. As a result, elbow medial force and elbow varus torque were generally increased as the lateral trunk tilt increased, that is the greater contra-lateral side-bending to the throwing arm side. On the other hand, the shoulder shear force was decreased as the lateral trunk tilt increased. Data from the study demonstrated that the shoulder proximal force was irrelevant to the trunk tilt angle.