Effects of Changing Angle of Release in Throwing for Distance on Velocity and Height of Release and Throwing Motion

Abstract

The purposes of this study were to find the optimal angle of release of ball throwing for distance, and to clarify effects of changing angle of release on throwing motion.In the experiment, 18 throws were performed by 8 female students. Angle of throwing was instructed indirectly by utilizing a simple device. Overhand throwing motions of subjects were videotaped simultaniously from side and overhead view by two video cameras. Angle, velocity and height of release were calculated from video analysis for 18 throws. Next, three throws which were near 20, 30 and 40 degree respectively were selected, and these throwing motions were analyzed.In all subjects, the greater the angle of release became, the less the velocity of release and the higher the height of release became. Calculating from the mutual relation among these three factors limiting throwing distance, the optimal angles of release were ranged from 33.8 to 39.4 degrees.The increase or decrease of velocity by changing angle of release was mainly influenced by actions of hand and forearm. Front and rear lean of upperbody was one of factors adjusting angle of release.