Exercise performance is regulated during repeated sprints to limit the development of peripheral fatigue beyond a critical threshold
Exercise performance is regulated during repeated sprints to limit the development of peripheral fatigue beyond a critical threshold
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DOI：
10.1113/expphysiol.2014.077974
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发表时间：
2014-07-01
影响因子：
2.7
通讯作者：
Blain, Gregory M.
中科院分区：
文献类型：
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作者：
Hureau, Thomas J.;Olivier, Nicolas;Blain, Gregory M.
我们假设，运动表现在重复冲刺期间会进行调整，以免超过外周疲劳的临界阈值。12名男性在不同的日子随机进行了三次实验，即一次10 s的全力冲刺和两次10 x 10 s的全力冲刺，中间有30 s的被动恢复。一项试验在非疲劳状态（CTRL）下进行，另一项试验在电诱导四头肌疲劳（FTNMES）后进行。通过比较股神经的超大磁刺激诱发的增强的四头肌抽搐力（Δ Q（tw-pot））的运动前和运动后变化来量化外周疲劳。通过比较运动前和运动后股四头肌运动单位的自主激活来估计中枢疲劳。还计算了短跑期间股外侧肌和股内侧肌EMG归一化为最大M波振幅（RMS.M-max（-1））的均方根（RMS）。与CTRL条件相比，FTNMES中预先存在的股四头肌疲劳（Δ Q（tw-pot）= -29 +/-4%）导致与RMS降低相关的功率输出（-4.0 +/-0.9%）显著（P < 0.05）降低。M-max（-1）。然而，三角洲Q（双锅）postsprints下降了51%，在这两种情况下，表明外周疲劳的水平是相同的，独立的程度预先存在的疲劳。我们的研究结果表明，功率输出和骑自行车的肌电图在运动过程中进行调整，以限制外周疲劳的发展超过一个恒定的阈值。我们推测，外周疲劳对运动受限的贡献除了肌肉功能受损外，还包括中枢运动驱动的减少。
We hypothesized that exercise performance is adjusted during repeated sprints in order not to surpass a critical threshold of peripheral fatigue. Twelve men randomly performed three experimental sessions on different days, i.e. one single 10 s all-out sprint and two trials of 10 x 10 s all-out sprints with 30 s of passive recovery in between. One trial was performed in the unfatigued state (CTRL) and one following electrically induced quadriceps muscle fatigue (FTNMES). Peripheral fatigue was quantified by comparing pre-with postexercise changes in potentiated quadriceps twitch force (Delta Q(tw-pot)) evoked by supramaximal magnetic stimulation of the femoral nerve. Central fatigue was estimated by comparing pre-with postexercise voluntary activation of quadriceps motor units. The root mean square (RMS) of the vastus lateralis and vastus medialis EMG normalized to maximal M-wave amplitude (RMS.M-max(-1)) was also calculated during sprints. Compared with CTRL condition, pre-existing quadriceps muscle fatigue in FTNMES (Delta Q(tw-pot) = -29 +/- 4%) resulted in a significant (P < 0.05) reduction in power output (-4.0 +/- 0.9%) associated with a reduction in RMS. M-max(-1). However, Delta Q(tw-pot) postsprints decreased by 51% in both conditions, indicating that the level of peripheral fatigue was identical and independent of the degree of pre-existing fatigue. Our findings show that power output and cycling EMG are adjusted during exercise in order to limit the development of peripheral fatigue beyond a constant threshold. We hypothesize that the contribution of peripheral fatigue to exercise limitation involves a reduction in central motor drive in addition to the impairment in muscular function.