抄録
The rotation of the golf-club around the long-axis of the shaft may be generated by two mechanisms. The 1^<st> mechanism is the angular impulse exerted by the golfer around the long-axis of the shaft directly. The 2^<nd> mechanism is the change in the orientation of the long-axis of the shaft with respect to the angular momentum of the golf-axis of the shaft in golf swing. A golfer performed 5-trials of "place shot" toward target away from 2m of the golfer. The electromagnetic tracking device was used to measure the three-dimensional motion of the golf-club. The angular velocity around the shaft was 1938±211°/s in the direction of "closed face" at ball impact. The angular velocity attributed to 1^<st> mechanism was 3543±378°/s in direction of "opened face", on the other hand the angular velocity attributed to 2^<nd> mechanism was 5400±312°/s in direction of "closed face" at impact. These results suggest that the angular impulse exerted by the golfer around the long-axis of the shaft be important to control the direction of the face.
