[[alternative]]THE EFFECTS OF GOLF SHAFT AND CLUBHEAD ON THE VELOCITY OF BALL

[[abstract]]The two major parts in golf club affect the ball velocity are club shaft and club- head. In general the club shaft and club head are made seperately and it is the golf club manufacturers who put these two parts together to make a club. For this reason, the shaft manufacturers and club head manufacturers often exaggerate their individual effect on the golf performance. However, there is little research on the effect of the shaft and the club head on the ball speed when the club hit the ball. The purpose of this study was to investigate 1) the influence of the bending stiffness of the golf shaft in different swing speed on the velocity of the ball, and 2) the influence of different club-heads in different swing speed on the velocity of the ball. Four different drivers made up of two different shaft stiffness (R-stiff, L-flexible) and club head (Titanium, Graphite) were used in the experiment. The participant was an amateur golfer and the swing speed was controlled in 35 m/sec and 45m/sec to test the clubs. The results showed that the shaft stiffness affected the bending degree of the shaft. The influence of different swing speed affected the duration of the force act on the clubs. The fast swing had little variation in shaft bending level than the slow swing. The speed of the club head affected the ball speed before impact. The shaft stiffness influenced the ball speed. The flexible shaft in slow swing speed had better advantage than the stiff one, but in fast swing speed different kinds of the shaft stiffness did not have significant effects on the ball speed. For the different kinds of swing speed the material of club head also make no significant effects on the ball speed. But the flexible shaft had the interaction in the material of club head for the swing speed. According to these results a golfer with a weak swing should use the flexible shaft to store more elastic energy in order to add the ball speed after impact. A golfer with a strong swing only needed to focus on the speed of club head because the shaft stiffness and club head material had little effect on the performance.