Nummela A, Vuorimaa T, Rusko H
Research Institute for Olympic Sports, Jyväskylä, Finland.
J Sports Sci. 1992 Jun;10(3):217-28. doi: 10.1080/02640419208729920.
The neural activation (iEMG) and selected stride characteristics of six male sprinters were studied for 100-, 200-, 300- and 400-m experimental sprints, which were run according to the velocity in the 400 m. Blood lactate (BLa) was analysed and drop jumps were performed with EMG registration at rest and after each sprint. Running velocity (P less than 0.001) and stride length (P less than 0.05) decreased and contact time increased (P less than 0.01) during the 400-m sprint. The increase in contact time was greatest immediately after runs of 100 and 300 m. The peak BLa increased and the rate of BLa accumulation decreased with running distance (P less than 0.001). The height of rise of the centre of mass in the drop jumps was smaller immediately after the 300 m (P less than 0.05) and the 400 m (P less than 0.01) than at rest, and it correlated negatively with peak BLa (r = -0.77, P less than 0.001). The EMG and EMG:running velocity ratio increased with running distance. It was concluded that force generation of the leg muscles had already begun to decrease during the first quarter of the 400-m sprint. The deteriorating force production was compensated for until about 200-300 m. Thereafter, it was impossible to compensate for fatigue and the speed of running dropped. According to this study, fatigue in the 400-m sprint among trained athletes is mainly due to processes within skeletal muscle rather than the central nervous system.
对六名男性短跑运动员在100米、200米、300米和400米实验性短跑中的神经激活（iEMG）和选定的步幅特征进行了研究，这些短跑是根据400米的速度进行的。分析了血乳酸（BLa），并在休息时以及每次短跑后进行了纵跳并记录肌电图。在400米短跑过程中，跑步速度（P<0.001）和步幅长度（P<0.05）下降，着地时间增加（P<0.01）。在跑完100米和300米后，着地时间的增加最为明显。随着跑步距离的增加，血乳酸峰值升高，血乳酸积累速率下降（P<0.001）。在跑完300米（P<0.05）和400米（P<0.01）后，纵跳时质心上升的高度比休息时小，并且与血乳酸峰值呈负相关（r = -0.77，P<0.001）。肌电图和肌电图与跑步速度的比值随跑步距离增加。得出的结论是，在400米短跑的第一季度，腿部肌肉的力量产生就已经开始下降。在大约200 - 300米之前，力量产生的恶化得到了补偿。此后，无法补偿疲劳，跑步速度下降。根据这项研究，训练有素的运动员在400米短跑中的疲劳主要是由于骨骼肌内的过程，而不是中枢神经系统。
