A study was conducted to investigate the relationships among changes of joint torque of the lower limbs, sprint ability such as sprint speed, stride length and stride frequency in 400 m running, and muscular endurance of the lower limbs. Subjects were 11 male track and field athletes who had a 400m running time of 48.75±1.32s. The experiment was composed of videotaping sprint form at 160 m and 360 m points during 400 m running, and measuring muscular endurance of hip and knee flexion and extension using Cybex NormTM.
The main results were as follows:
1) There was a significant relationship between 400 m running time and ability to maintain a higher running speed at the 360 m point.
2) Running speed, stride length and stride frequency decreased significantly at the 360 m point.
3) Subjects who showed a smaller decrease in stride frequency at the 360 m could maintain higher running speed.
4) Subjects who showed smaller decrease in maximal joint torque of the lower limbs at the 360 m could maintain a higher running speed.
5) There was a significant relationship between an increase in support time and decrease in maximal joint torque of hip extension for the recovery leg.
6) Ability to maintain joint torque during 400 m running was influenced by muscular endurance of the lower limbs.
These results suggest that the ability to maintain torque needed for higher performance in 400 m running is influenced by muscular endurance of the lower limbs.