<p>This study examined the effects of hip joint kinetics on pelvic rotation about the superior-inferior (SI) axis during baseball pitching from the viewpoint of energetics. Twelve right-handed males participated and all used an overarm style. Five participants were active collegiate baseball players and seven participants were former collegiate baseball players. Each participant was instructed to try their maximum effort pitch from an indoor pitching mound. Three pitches per participant that passed through the strike zone were selected for analysis. A motion capture system consisting of 13 cameras and two force platforms were used to collect data and calculate joint torques. Pelvic rotation torque, mechanical energy generation, and transfer were calculated. The hip external rotation torque transferred the mechanical energy from the thigh to the pelvis in the pivot leg, which mainly increased the mechanical energy of the pelvis about the SI axis. Regarding the stride leg, the hip adduction torque generated the mechanical energy, which mainly increased the mechanical energy of the pelvis about the SI axis. The findings highlight the importance of these torques in rotating the pelvis about the SI axis.</p>