PURPOSE Several mechanisms have been proposed to explain how mental fatigue degrades sport performance. In terms of endurance performance, a role for an increased perceived exertion has been demonstrated. Utilizing electroencephalography (EEG) and, more specifically, the movement-related cortical potential (MRCP), the present study explored the neural mechanisms that could underly the mental fatigue-associated increase in perceived exertion. METHODS Fourteen participants (age: 23 ± 2 y, 5 females, 9 males) performed one familiarisation and two experimental trials in a randomised, blinded, cross-over study design. Participants had to complete a submaximal leg extension task after a mentally fatiguing task (EXP; individualized 60-min Stroop task) or control task (CON; documentary). The leg extension task consisted of performing 100 extensions at 35% of 1RM, during which multiple physiological (heart rate, EEG, ratings of perceived exertion) and psychological measures (self-reported feeling of mental fatigue, cognitive load, motivation) were assessed. RESULTS Self-reported feeling of mental fatigue was higher in EXP (72 ± 18) compared to CON (37 ± 17; p < 0.001). A decrease in flanker accuracy was detected only in EXP (from 0.96 ± 0.03 to 0.94 ± 0.03; p < 0.05). No significant differences between conditions were found in MRCP characteristics and perceived exertion. Specifically in EXP, alpha wave power increased during the leg extension task (p < 0.01). CONCLUSIONS Mental fatigue did not impact the perceived exertion or MRCP characteristics during the leg extension task. This could be related to low perceived exertion and/or the absence of a performance outcome during the leg extension task. The increase in alpha power during the leg extension task in EXP, suggests participants may engage a focused internal attention mechanism to maintain performance and mitigate feelings of fatigue.

中文翻译：

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精神疲劳对力量耐力任务的影响：运动相关的皮质电位是否有作用？

目的已经提出了几种机制来解释精神疲劳如何降低运动表现。在耐力表现方面，已证明了增加感知努力的作用。本研究利用脑电图（EEG），更具体地说，利用运动相关皮层电位（MRCP），探索了与精神疲劳相关的感知用力增加的神经机制。方法 14 名参与者（年龄：23​​ ± 2 岁，5 名女性，9 名男性）在随机、盲法、交叉研究设计中进行了一项熟悉试验和两项实验试验。参与者必须在精神疲劳任务（EXP；个性化 60 分钟斯特鲁普任务）或控制任务（CON；纪录片）之后完成次最大腿部伸展任务。腿部伸展任务包括以 1RM 的 35% 进行 100 次伸展，在此期间评估多种生理（心率、脑电图、感知用力评级）和心理测量（自我报告的精神疲劳感、认知负荷、动机）。结果 EXP 组自我报告的精神疲劳感 (72 ± 18) 高于 CON 组 (37 ± 17；p < 0.001)。仅在 EXP 中检测到侧翼精度下降（从 0.96 ± 0.03 至 0.94 ± 0.03；p < 0.05）。MRCP 特征和感知用力情况之间没有发现显着差异。特别是在 EXP 中，腿部伸展任务期间 α 波功率增加 (p < 0.01)。结论 在腿部伸展任务期间，精神疲劳不会影响感知的用力或 MRCP 特征。这可能与腿部伸展任务期间感觉用力低和/或缺乏表现结果有关。EXP 中腿部伸展任务期间阿尔法功率的增加表明参与者可能会采用集中的内部注意力机制来保持表现并减轻疲劳感。