Department of Nutrition and Human Sciences, University of Nebraska- Lincoln, Lincoln, USA.
Department of Health, Kinesiology and Sport, University of South Alabama, Mobile, USA.
J Musculoskelet Neuronal Interact. 2021 Mar 1;21(1):4-12.
The purpose of the present study was to compare the fatigue-induced changes in performance fatigability, bilateral deficit, and patterns of responses for the electromyographic (EMG) and mechanomyographic (MMG) amplitude (AMP) and mean power frequency (MPF), during unilateral and bilateral maximal, fatiguing leg extensions.
Nine men (Mean±SD; age =21.9±2.4 yrs; height =181.8±11.9 cm; body mass =85.8±6.2 kg) volunteered to perform 50 consecutive maximal, bilateral (BL), unilateral dominant (DL), and unilateral non-dominant (NL) isokinetic leg extensions at 180°·s, on 3 separate days. Electromyographic and MMG signals from both vastus lateralis (VL) muscles were recorded. Repeated measures ANOVAs were utilized to examine mean differences in normalized force, EMG AMP, EMG MPF, MMG AMP, MMG MPF and the bilateral deficit.
The results demonstrated a Condition × Repetition interaction for normalized force (p=0.004, η=0.222) and EMG MPF (p=0.034, η=0.214) and main effects for Repetition for EMG AMP (p=0.019, η=0.231), MMG AMP (p<0.001, η=0.8550), MMG MPF (p=0.009, η=0.252), and the bilateral deficit (p<0.001, η=0.366).
The findings demonstrated less performance fatigability during the BL than the unilateral tasks, likely due to a reduced relative intensity via interhemispheric inhibition that attenuated the development of excitation-contraction coupling failure during the BL task.
本研究旨在比较单侧和双侧最大疲劳性腿屈伸时，肌肉疲劳导致的肌肉电（EMG）和机械电（MMG）幅度（AMP）和平均功率频率（MPF）的性能疲劳性、双侧缺陷和反应模式的变化。
9 名男性（均值±标准差；年龄=21.9±2.4 岁；身高=181.8±11.9cm；体重=85.8±6.2kg）自愿在 3 天内，以 180°·s 的速度连续进行 50 次双侧（BL）、单侧优势（DL）和单侧非优势（NL）的最大等速腿屈伸运动。记录双侧股外侧肌（VL）的肌电和 MMG 信号。采用重复测量方差分析来检验归一化力、EMG AMP、EMG MPF、MMG AMP、MMG MPF 和双侧缺陷的均值差异。
结果表明，归一化力（p=0.004，η=0.222）和 EMG MPF（p=0.034，η=0.214）存在条件×重复交互作用，而 EMG AMP（p=0.019，η=0.231）、MMG AMP（p<0.001，η=0.8550）、MMG MPF（p=0.009，η=0.252）和双侧缺陷（p<0.001，η=0.366）存在重复主效应。
研究结果表明，与单侧任务相比，BL 时的运动表现疲劳性较低，这可能是由于通过半球间抑制降低相对强度，从而减轻了 BL 任务中兴奋-收缩耦联失败的发展。
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