Relationship of Selected Measures of Acting Body Levers to Ball-Throwing Velocities

Abstract

The purpose of the study was to determine the relationship between selected measures of body levers contributing to throwing and the ball velocities achieved in the overhand and underhand throws. Motion picture data were obtained of the throwing performance of 42 high school girls, arranged in three groups on the basis of differences in initial throwing velocity achievement. Structure length and moment-arm measures of acting body levers for trunk rotation, medial rotation and flexion of the arm, and flexion of the wrist were studied. These subjects demonstrated a pattern of acting lever length contribution to overhand throwing velocity. Moment-arm measures of acting levers were found to have considerable predictive power relative to the overhand throwing velocity achieved. A similar relationship was not found between structure-length measures and overhand throwing velocity. Results with the underhand throws indicated that neither length of body segments nor the position of the acting lever at the moment of release of the ball was a critical factor in determining the velocity of the throw.