This study was conducted to clarify the mechanism of body rotation by the lower limbs in the baseball pitcher throwing motion. Twenty male overhead baseball pitchers participated in this study voluntarily. All participants threwthree fastball pitches with maximal effort toapitching net located in front of the pitcher. In all, 60 pitching motions were captured. An optical motion capture system and two force plates were used for kinematic and kinetic measurements. The ball speed at ball release, joint angles, joint moments and joint power in lower extremities, moment around the center of mass (COM), and body angular momentum about COM were derived. This study demonstratedthat the body\u27s angular momentum was acquired first around the Z axis (horizontal rotation), then around the X axis (vertical rotation), and finallyaround the Z axis after FFC. Hip joint moment was important for generating each rotation motion
