Yang Hyung Suk, Atkins Lee T, James C Roger
Division of Kinesiology and Sport Management, University of South Dakota, Vermillion, South Dakota, United States of America.
Center for Rehabilitation Research, Texas Tech University Health Sciences Center, Lubbock, Texas, United States of America.
PLoS One. 2025 Mar 12;20(3):e0318238. doi: 10.1371/journal.pone.0318238. eCollection 2025.
This study investigated the effects of mental fatigue on rate of force development (RFD) and peak force during an isometric mid-thigh pull (IMTP), as well as its impact on muscle activation measured by electromyography (EMG) median frequency. Sixteen healthy, resistance-trained males completed two sessions: a control condition and a mentally fatigued state induced by a 30-minute modified Stroop task. IMTP performance and muscle activation were assessed before and after the mental fatigue task. Mental fatigue significantly reduced RFD in the later phase of force generation, specifically within the 20%-80% of maximum force interval (RFD2080) (p = 0.022, d = 0.638). In contrast, no significant changes were observed in RFD within the initial 0-100 milliseconds (RFD100) or 0-200 milliseconds (RFD200) of contraction, nor in peak force. Additionally, mental fatigue led to a significant increase in EMG median frequency for the rectus femoris during the initial 0-1 second interval (p = 0.040, d = -0.609), with no significant changes in the medial gastrocnemius or other time intervals. These findings suggest that mental fatigue primarily impacts the later stages of force development, affecting the ability to sustain and develop force over time without compromising peak force. The increase in EMG median frequency for the rectus femoris indicates a possible compensatory response to mental fatigue, underscoring the complex influence of cognitive stress on neuromuscular function. This study highlights the importance of considering mental fatigue in activities requiring sustained or progressively increasing force production.
本研究调查了心理疲劳对等长中大腿拉力（IMTP）过程中的力量发展速率（RFD）和峰值力量的影响，以及其对通过肌电图（EMG）中位频率测量的肌肉激活的影响。16名健康的、有抗阻训练经验的男性完成了两个阶段：一个对照条件和一个由30分钟改良斯特鲁普任务诱导的心理疲劳状态。在心理疲劳任务前后评估IMTP表现和肌肉激活情况。心理疲劳显著降低了力量产生后期的RFD，特别是在最大力量区间的20%-80%（RFD2080）内（p = 0.022，d = 0.638）。相比之下，在收缩的最初0-100毫秒（RFD100）或0-200毫秒（RFD200）内的RFD以及峰值力量均未观察到显著变化。此外，心理疲劳导致股直肌在最初0-1秒内的EMG中位频率显著增加（p = 0.040，d = -0.609），而腓肠肌内侧或其他时间段没有显著变化。这些发现表明，心理疲劳主要影响力量发展的后期阶段，影响随着时间维持和发展力量的能力，而不影响峰值力量。股直肌EMG中位频率的增加表明对心理疲劳可能存在代偿反应，强调了认知应激对神经肌肉功能的复杂影响。本研究强调了在需要持续或逐渐增加力量产生的活动中考虑心理疲劳的重要性。
