RELATIONSHIP BETWEEN THE ABILITY TO MAINTAIN JOINT TORQUE AND MUSCULAR ENDURANCE OF LOWER LIMBS DURING 400m RUNNING / 体力科学

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.<BR>The main results were as follows:<BR>1) There was a significant relationship between 400 m running time and ability to maintain a higher running speed at the 360 m point.<BR>2) Running speed, stride length and stride frequency decreased significantly at the 360 m point.<BR>3) Subjects who showed a smaller decrease in stride frequency at the 360 m could maintain higher running speed.<BR>4) Subjects who showed smaller decrease in maximal joint torque of the lower limbs at the 360 m could maintain a higher running speed.<BR>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.<BR>6) Ability to maintain joint torque during 400 m running was influenced by muscular endurance of the lower limbs.<BR>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.

Relationship between sprint ability under the condition of muscular fatigue, and physical fitness factors / 体力科学

The influence of aerobic and anaerobic components of muscular endurance on the lower limbs, on sprint ability while under conditions of muscular fatigue, was investigated. Fifteen track and field athletes (400 m sprinters, decathletes and middle distance runners) participated in the study in which running and sprinting movements at respective points (360 m and 50 m) along two distance conditions (400 m and 80 m, respectively), were filmed by high-speed video camera. Running speeds at each point were computed from the film analysis. The running speed at 360 m point was defined as the speed under fatigue, while the running speed at the 50m point was defined as the maximal speed. Further, the rate between speed under fatigue and maximal speed was defined as %Max. Speed. Maximal O<SUB>2</SUB> intake, O<SUB>2</SUB> debt and isokinetic muscular endurance were measured.<BR>The results were summarized as follows :<BR>1) Oxygen debt showed significant correlation with the average speed during 400m running (r=0.546 ; p<0.05), but not with the speed under fatigue (r=0.388 ; p>0.05) .<BR>2) Speed under fatigue was positively correlated with muscular endurance of hip flexion and extension (r=0.683 ; p<0.01, r=0.572 ; p<0.05) .<BR>3) Percent Max. Speed was negatively correlated with the maximal speed (r = -0.643 ; p <0.01) and positively correlated with the muscular endurance of hip flexion and extension, and knee flexion (r=0.640 ; p <0.05, r=0.517 ; p<0.05, r=0.646 ; p<0.01) .<BR>These results suggest that; raising %Max. Speed to improve the muscular endurance of lower limbs and, to improve aerobic ability by developing the number of capillaries in the muscle, is important.