Abstract
The purpose of this study was to clarify the mechanisms to develop the racket velocity for wheelchair tennis player. The subjects were ten wheelchair tennis players and four able-bodied tennis coaches. This study used a motion capture system to obtain the three-dimensional coordinates of markers attached to subjects and the tennis racket during the serve. The findings are summarized as follows.
1）Wheelchair tennis players with high racket velocity served using shoulder internal rotation and wrist palmar flexion in the same way as able-bodied tennis players.
2）Wheelchair tennis players with high racket velocity increased the maximum angle of shoulder external rotation by restricting shoulder horizontal flexion as much as possible during the first half of the forward swing，and used the rebound movement to develop the angular velocity of shoulder internal rotation.
3）In wheelchair tennis，it is important to abduct the shoulder and to extend the elbow as far as possible in order to obtain a higher hitting point. However，in order to increase the racket velocity，the elbow has to be bent slightly so that the angular velocity of shoulder internal rotation is effectively transferred to the racket velocity.
