Univ Lyon, UJM-Saint-Etienne, Inter-university Laboratory of Human Movement Biology, EA 7424, Saint-Etienne, F-42023, France.
Clermont-Auvergne University, AME2P, Clermont-Ferrand, 63000, France.
Exp Physiol. 2021 Mar;106(3):663-672. doi: 10.1113/EP089177. Epub 2021 Jan 18.
What is the central question of this study? Are spinal and/or supraspinal perturbations implicated in central fatigue induced in the plantar flexor muscles following prolonged trail running races? What is the main finding and its importance? The study confirmed the presence of central fatigue following various trail running distances from 40 to 170 km. The reduction in the V-wave in conjunction with the lack of change in the H-reflex suggests that a major component of this central fatigue may arise from supraspinal mechanisms in the plantar flexor muscles.
Trail running races are known to induce considerable impairments in neuromuscular function of which central mechanisms are a substantial component. However, the loci of this central fatigue (i.e. supraspinal and/or spinal) is not well identified. The aim of this study was to better understand central fatigue aetiology induced in the plantar flexor muscles by various trail running distances from 40 to 170 km. Eighteen runners participated in the study and neuromuscular function of their plantar flexors was tested before (PRE) and after (POST) various races during the Ultra-Trail du Mont Blanc. Neuromuscular function was evaluated with voluntary and evoked contractions using electrical tibial nerve stimulation. H-reflex and V-wave responses were also measured during submaximal and maximal voluntary contraction, respectively. Reductions in maximal voluntary contraction torque (-29%; P < 0.001) and voluntary activation level (-12%; P < 0.001) were observed after trail running races. The V-wave was reduced in soleus (-35%; P = 0.003) and gastrocnemius medialis (-28%; P = 0.031), with no changes for the H-reflex in soleus (P = 0.577). The present study confirmed the presence of central fatigue following trail running exercise. The reduction in the V-wave in conjunction with the lack of change in the H-reflex suggests that a major component of this central fatigue may arise from supraspinal mechanisms.
这项研究的核心问题是什么？长时间的越野跑比赛是否会导致足底屈肌的中枢疲劳，涉及到脊髓和/或脊髓以上的扰动？主要发现及其重要性是什么？本研究证实，在进行 40 至 170 公里的各种越野跑比赛后，会出现中枢疲劳。V 波的降低伴随着 H 反射没有变化，这表明这种中枢疲劳的一个主要组成部分可能来自于足底屈肌的脊髓以上机制。
众所周知，越野跑比赛会导致相当大的神经肌肉功能障碍，其中中枢机制是一个重要组成部分。然而，这种中枢疲劳的部位（即脊髓以上和/或脊髓）尚不清楚。本研究的目的是更好地了解 40 至 170 公里各种越野跑比赛后足底屈肌的中枢疲劳的病因。18 名跑步者参加了这项研究，在 Ultra-Trail du Mont Blanc 期间的各种比赛前后，测试了他们的足底屈肌的神经肌肉功能。使用电刺激胫神经进行自愿和诱发收缩来评估神经肌肉功能。还分别在最大自主收缩和最大随意收缩期间测量 H 反射和 V 波反应。越野跑比赛后，最大自主收缩扭矩（-29%；P<0.001）和自愿激活水平（-12%；P<0.001）均下降。在比目鱼肌（-35%；P=0.003）和腓肠肌内侧（-28%；P=0.031）中，V 波降低，而比目鱼肌中的 H 反射没有变化（P=0.577）。本研究证实，越野跑运动后会出现中枢疲劳。V 波的降低伴随着 H 反射没有变化，这表明这种中枢疲劳的一个主要组成部分可能来自于脊髓以上的机制。
