Nummela A, Rusko H, Mero A
Research Institute for Olympic Sports, Jyväskylä, Finland.
Med Sci Sports Exerc. 1994 May;26(5):605-9.
The present study was designed to investigate EMG activities and ground reaction forces during fatigued and nonfatigued running. Ten male sprint runners volunteered to run a maximal 20-m speed test, a 400-m time trial, and submaximal 20-m runs at the average speed of the first 100 m of the 400 m. During the latter stage of each run, ground reaction forces and EMG activity of four leg muscles were recorded. EMG activities were time averaged during three phases of running: preactivation, braking, and propulsion phase. The resultant ground reaction forces both in the braking (P < 0.001) and in the propulsion phase (P < 0.01) were greater in the maximal and submaximal 20 m than at the end of the 400 m. The averaged EMG during the braking phase (P < 0.01) and during the total ground phase (P < 0.05) was smaller in the submaximal 20 m than at the end of the 400 m. On the other hand the averaged EMG was greater during the maximal 20 m than at the end of the 400 m during the propulsion phase (P < 0.001) and during the total ground phase (P < 0.05). In addition, the more the preactivity increased the less the resultant ground reaction force decreased in the braking phase during the 400 m run (r = 0.77, P < 0.05). It was concluded that the role of the increased neural activation was to compensate for muscular fatigue and the preactivation had an important role in maintaining force production during the 400-m run. In addition, the fatigue was different in each working muscle.
本研究旨在调查疲劳和非疲劳跑步过程中的肌电图（EMG）活动和地面反作用力。十名男性短跑运动员自愿参加了一项最大20米速度测试、一项400米计时赛以及以400米前100米的平均速度进行的次最大强度20米跑步。在每次跑步的后期，记录了四条腿部肌肉的地面反作用力和肌电图活动。肌电图活动在跑步的三个阶段进行时间平均：预激活、制动和推进阶段。在最大强度和次最大强度的20米跑步中，制动阶段（P < 0.001）和推进阶段（P < 0.01）的合成地面反作用力均大于400米跑步结束时。次最大强度20米跑步中制动阶段（P < 0.01）和整个地面阶段（P < 0.05）的平均肌电图小于400米跑步结束时。另一方面，在推进阶段（P < 0.001）和整个地面阶段（P < 0.05），最大强度20米跑步时的平均肌电图大于400米跑步结束时。此外，在400米跑步的制动阶段，预激活增加越多，合成地面反作用力下降越少（r = 0.77，P < 0.05）。研究得出结论，神经激活增加的作用是补偿肌肉疲劳，并且预激活在400米跑步过程中维持力量产生方面具有重要作用。此外，每个工作肌肉的疲劳情况不同。
