THE ANALYSIS OF ANGULAR MOMENTUM OF SIDE-VOLLEY SOCCER SHOTS PERFORMED AT THREE BALL-HEIGHT

Abstract

The purpose of this study was to examine side-volley soccer shots performed at three ballheight. Five amateur, right leg dominant, male soccer players (height = 173 ±2.86 cm; weight = 68 ±6.04 kg; age = 20.5 ±0.5 yrs) participated in this study. Two electrically synchronized highspeed video cameras (Redlake) were used to sample the kicking motion at 250 Hz. By the three-dimensional cinematographic technical analysis, the kicking leg was modeled as a threelink kinetic chain composed of thigh, shank, and foot, from which angular velocities and angular momentum were computed. Significantly greater ball velocity and foot velocity were achieved in kicking lower ball-height, with a shorter leg-swing time. The foot moment of inertia exhibited a high value in side-volley shot performed at the lower ball-height. These results indicated that the side-volley soccer shots performed at the lower ball-height would made higher value of foot angular momentum, and benefited ball velocity.