抄録
Unlike the short sprint, it is known that the body cannot complete the 400–m race at maximum effort, and sprinters need to utilize mechanical energy effectively to control fatigue during the race. The purpose of this study was to clarify the relationship between the effectiveness index (EI) of mechanical energy utilization (assessed by stride length divided by mechanical work) and 400–m sprint performance. Twelve collegiate sprinters ran the 400–m distance. EI was calculated from kinematic data at the 160–m and 360-m points. EI at the 160–m point was negatively correlated with the 400–m running time (r = − 0.797，p <0.01), whereas EI at the 360–m point was positively correlated (r = 0.836，p <0.001). EI at the 160-m point was positively correlated with the segment torque power (r = 0.614，p <−0.05) and hip flexion peak power (r = 0.588，p <0.05) during the forward swing. These results suggest that the key to improving 400–m sprint performance is to utilize mechanical energy effectively in the early phase and generate more mechanical energy in the late phase. Additionally, emphasizing thigh forward swing movements seems to be an effective means of utilizing mechanical energy in the early phase.
