以穿戴式裝置比較不同層級棒球打者軀幹 及手部之揮棒技術.

Introduction: Inertial measurement units (IMUs) have accurately detected kinematic parameters during baseball batting. This study aimed to investigate differences in hip, upper torso, and hand kinematics between elite and sub-elite college baseball batters during the stride and swing batting phases. Methods: Six elite and six sub-elite college players participated in this study. Three IMUs were attached to the hip, upper torso, and back of the batting hand to detect the timing of stride and swing phases, peak hip horizontal acceleration, peak rotational angular velocity, and peak upper torso rotational angular velocity at the foot-off and foot-on of the front foot. During the swing phase, peak hip velocity, peak upper torso velocity, peak hand velocity, and the duration from the three different body position's peak rotational angular velocity to contact between the bat and the ball were collected. Kinematic differences between elite and sub-elite batters were assessed using Mann- Whitney U tests. Result: The stride phase was shorter in elite college batters than in sub-elite players (p < .01), while the swing phase was longer in elite players than in sub-elite batters (p < .01). The hip horizontal acceleration, hip angular velocity, and chest angular velocity at foot-on were lower in elite batters than in sub-elite batters (p < .01). However, hip, chest, and hand angular velocities during the swing phase were higher in elite batters than in sub-elite batters (p < .01). Moreover, a shorter duration between each body segment's peak velocity and contact between the bat and the ball was observed in elite batters than in sub-elite batters (p < .01). Conclusion: Elite and sub-elite college batters showed differences in timings, front foot-on, and kinematics of the hip, upper torso and hand during the swing phase. Specifically, a shorter stride phase and reduced hip and chest rotation at foot planting were found for elite batters compared to sub-elite batters. In contrast, elite batters prolonged the swing phase and developed higher hip, chest, and hand velocities closer to impact. This study's findings and applied method of IMU usage may contribute to performance assessment practices and improving batting skills. [ABSTRACT FROM AUTHOR]