Abstract
We have mainly focused on the elucidation of the physical skills of sports players. We have especially evaluated these skills from the biomechanical data obtained from sports. In this study, we analyzed the swing motions of skilled and unskilled baseball players by using two tri-axial acceleration sensors and two high-speed cameras. We showed some results of the skill rules of the swing motions by the skilled and unskilled players. It was also indicated that acceleration sensors are more convenient than the motion capture system for extracting skills from some data.