A comparison of kinetics in the lower limbs between baseball tee and pitched ball batting

In this study, the kinetic characteristics of lower limbs during batting were investigated by comparing batting off a tee with batting a pitched ball. Participants were 10 male collegiate baseball players who performed tee batting (TB) and batting using a pitching machine (MB; approximate ball speed: 33.3 m/s). Three-dimensional coordinate data were acquired using a motion capture system, and ground reaction forces were measured using three force platforms. Lower limb joint torques were obtained by inverse dynamics calculations. The results indicated that the angular velocity of the lower trunk was larger in TB than in MB for rotation. The swing time from stride foot contact with the ground to ball impact was significantly longer in MB than in TB. The angular impulses of bilateral hip adduction, pivot hip external rotation, and stride hip and knee extension torques were significantly larger in MB, suggesting that batters exert these joint torques earlier for pitched balls to handle time constraints by changing the rotation of the lower trunk in response to the unknown ball location and speed in MB. These findings will help to fill a gap in the literature and provide coaching insights for improving batting motion.