Abstract
The present study focused on the behavior of the ball at the time of the stroke in soft tennis, and it aimed at exploring the relations of many kinematic values at impact, and the flight behavior of the ball, while checking whether there might be an abnormal flight behavior. The flight of the ball was videotaped by three sets of video cameras, and the ball at impact was videotaped with two high speed cameras. The behaviors of these balls were analyzed. These experiments investigated the conditions of the flights of soft tennis balls, both when given a lift from an applied drive rotation and when given a sinking flight from a slice rotation. It was suggested that the difference in rate of spin given by a stroke influenced the abnormal flight behavior of a soft tennis ball, and also that when there was drive rotation or slice rotation of 40rps or more, the possibility of abnormal flight behavior occurring was high.
