Billaut François, Demers Marie Rousseau, Hibbert Andrew
Département de kinésiologie, Université Laval, Québec, QC, CANADA.
Institute for Health & Sport, Victoria University, Melbourne, VIC, AUSTRALIA.
Int J Exerc Sci. 2023 Aug 1;16(1):987-998. doi: 10.70252/RLSM7428. eCollection 2023.
The regulation of exercise intensity allows an athlete to perform an exercise in the fastest possible time while avoiding debilitating neuromuscular fatigue development. This phenomenon is less studied during intermittent activities. To investigate anticipatory and real-time regulation of motor output and neuromuscular fatigue during repeated-sprint exercise, twelve males randomly performed one (S1), two (S2), four (S4) and six (S6) sets of five 5-s cycling sprints. Mechanical work and electromyographic activity were assessed during sprints. Potentiated quadriceps twitch force (ΔQ) and central activation ratio (Q) were quantified from response to supra-maximal magnetic femoral nerve stimulation pre- post-exercise. Compared with S1, mechanical work developed in the first sprint and in the entire first set was reduced in S6 (-7.8% and -5.1%, respectively, 0.05). Work developed in the last set was similar in S4 and S6 ( 0.82). Similar results were observed for EMG activity. The Q was also more reduced in S4 (-5.8%, 0.05) and S6 (-8.3%, 0.05) than in S1. However, ΔQ was not significantly different across all trials (-33.1% to -41.9%, 0.46). Perceived exhaustion increased across sprints to reach a maximal and similar level in S2, S4 and S6 (all 19.2, < 0.01 vs S1). These results suggest that the regulation of performance, exerted at the beginning and continuously during repeated sprints, is based on the task endpoint, presumably to avoid excessive peripheral muscle and associated conscious overwhelming sensations.
运动强度的调节使运动员能够在尽可能短的时间内完成一项运动，同时避免使人衰弱的神经肌肉疲劳的发展。在间歇性活动中，这种现象的研究较少。为了研究重复冲刺运动中运动输出和神经肌肉疲劳的预期调节和实时调节，12名男性随机进行了一组（S1）、两组（S2）、四组（S4）和六组（S6）每组五次5秒的自行车冲刺。在冲刺过程中评估机械功和肌电图活动。通过运动前后对超最大股神经磁刺激的反应，量化股四头肌增强抽搐力（ΔQ）和中枢激活率（Q）。与S1相比，S6中第一次冲刺和整个第一组所产生的机械功降低（分别为-7.8%和-5.1%，P<0.05）。S4和S6最后一组所产生的功相似（P>0.82）。肌电图活动也观察到类似结果。S4（-5.8%，P<0.05）和S6（-8.3%，P<0.05）中的Q也比S1中降低得更多。然而，所有试验中的ΔQ没有显著差异（-33.1%至-41.9%，P>0.46）。随着冲刺次数的增加，感觉到的疲劳感增加，在S2、S4和S6中达到最大且相似的水平（均为19.2，与S1相比P<0.01）。这些结果表明，在重复冲刺开始时并在整个过程中发挥作用的运动表现调节是基于任务终点的，大概是为了避免外周肌肉过度疲劳以及相关的意识上的压倒性感觉。
