Abstract
Recently, it is proposed that oversized ball is used in the official games. Effects on the player in using he oversized ball are not clear still. Especially effects on the elbow have to be analyzed as soon as possible to prevent the tennis elbow. In this paper, we solve the dynamical effects on the elbow in hitting an oversized tennis ball in comparison with the normal sized ball. When a player blows the ball in the court, the acceleration and the bending angle of player's elbow, the grip pressure, and the 3-dimentional positions of a racket and a ball were measured. As the parameter, three type of the tension of the gut string were chosen. The result shows that hitting the normal sized ball at the top of the racket had more effect on the elbow.
