AN APPROACH OF RELATIVE MOTION ANALYSIS FOR CALCULATING SEGMENTS CONTRIBUTION TO THE WORK DONE TO THE BASEBALL

Abstract

A mathematical model of the trunk and upper extremity was developed to investigate the kinetic contributions to power flow to the baseball in pitching. In the model, linear acceleration and linear velocity of the ball, for calculating power, were replaced with some anatomical angular accelerations and velocities. The model was applied to three professional baseball pitchers. Previously published data from three professional pitchers were used as input to a three-segment model of a throwing arm. Greater contributions were found in the forearm movement (18-20%) and its interaction with other segments, especially hand segment (37-46%). Though independent contribution of the upper arm movement was insignificant (2-4%), its interaction contributions by cooperating with other segments were considerable (8-15%).