The purpose of this study was to investigate a relationship between finger force and upper limb kinematics for baseball pitching. Two collage baseball pitchers participated in the experiment and threw a four-seam fastball 10 times. A force transducer was installed in a baseball to make a direct measurement of force imparting on the ball by index finger during pitching (2000 Hz). A pitching motion was captured using 12 infrared cameras (500 Hz). The finger force showed a bimodal pattern for both participant. The 1st peak appeared at a moment of maximum shoulder external rotation (45-50 ms before instant of ball release). The 2nd peak appeared at 7-8 ms before instant of ball release. It was considered that the 2nd peak reflected angular velocity of shoulder internal rotaion.
