Abstract
This paper investigated the feel or comfort of the arm or hand in an impact. It derived the shock vibrations of the wrist joint caused by the impact when a player hits flat forehand drive. Furthermore, it predicted the sweet spots of a racket in terms of feel. It was based on the identification of the racket-arm system and the predicted coefficient of restitution between a racket and a ball. The predicted waveform of the shock vibrations at the wrist joint agreed fairly well with the measured ones during actual forehand stroke by a player, showing that the shock vibrations of the wrist joint are transmitted from an impulse at the impact location and the several vibrations mode components of the racket. The predicted results could also explain the difference in sweet spots of a racket in terms of feel or comfort of rackets with different weight and weight balance. This study enables us to predict the various factors associated with impact and performance of the various racket.
