Abstract
In this study, we developed a system measuring bat behavior during a baseball swing by mounting an inertial sensor unit which incorporated the acceleration sensor and the gyro sensor to bat grip end. We compared the bat behavior that measured by between developed system and three-demensional motion capture system (MAC3D system; Motion Analysis). As a result, accuracy of the bat behavior calculated by developed system was varified. Furthremore, we defined eight parameters to express a characteristic of the bat behavior. In this way, players and coachers can evaluate baseball swing quantitatively. Eight parameters are "swing time", "swing speed (impact)", "swing speed (max)", "impact acceleration", "rolling", "bat radius of rotation", "bat angle" and "swing orbit".
