Influence of Fatigue on Hand Muscle Coordination and EMG-EMG Coherence During Three-Digit Grasping
Influence of Fatigue on Hand Muscle Coordination and EMG-EMG Coherence During Three-Digit Grasping
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DOI：
10.1152/jn.00583.2010
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发表时间：
2010-12-01
影响因子：
2.5
通讯作者：
Santello, Marco
中科院分区：
文献类型：
--
作者：
Danna-Dos Santos, Alessander;Poston, Brach;Santello, Marco
[10]张文龙，张文龙.疲劳对三指抓握时手部肌肉协调性和肌电一致性的影响。J Neurophysiol 104：3576-3587，2010.首次发表于2010年10月6日; doi：10.1152/jn.00583.2010。指尖力控制需要手指内和手指间多个手部肌肉的精细协调。虽然作为力的函数的神经驱动对手部肌肉的调制已经被广泛研究，但是关于疲劳对同时活动的手部肌肉的协调的影响知之甚少。我们要求8名受试者通过用拇指、食指和中指握住一个巨大的操纵器来进行疲劳收缩，同时尽可能长时间地匹配等长的目标力（40%最大随意力）。12只手肌肉的协调性被量化为肌电图（EMG）肌肉激活模式（MAP）向量和EMG-EMG相干性。我们假设肌肉疲劳会导致所有肌肉的EMG振幅均匀变化，并在较高频段增加EMG-EMG相干性，但在肌肉中具有不变的异质分布。肌肉疲劳导致任务失败时最大自主收缩力下降12.5%（P < 0.05），力的SD增加（P < 0.01）。虽然在疲劳收缩过程中所有肌肉的EMG幅度都增加（P < 0.001），但MAP矢量方向没有改变，表明在整个疲劳收缩过程中使用了类似的肌肉协调模式。最后，肌电-肌电相干性（0-35 Hz）在疲劳收缩结束时显著大于开始时（P < 0.01），但在手部肌肉中分布不均匀。这些研究结果表明，类似的机制涉及调制和维持手指的力量，在非疲劳和疲劳收缩，分别。
Danna-Dos Santos A, Poston B, Jesunathadas M, Bobich LR, Hamm TM, Santello M. Influence of fatigue on hand muscle coordination and EMG-EMG coherence during three-digit grasping. J Neurophysiol 104: 3576-3587, 2010. First published October 6, 2010; doi:10.1152/jn.00583.2010. Fingertip force control requires fine coordination of multiple hand muscles within and across the digits. While the modulation of neural drive to hand muscles as a function of force has been extensively studied, much less is known about the effects of fatigue on the coordination of simultaneously active hand muscles. We asked eight subjects to perform a fatiguing contraction by gripping a manipulandum with thumb, index, and middle fingers while matching an isometric target force (40% maximal voluntary force) for as long as possible. The coordination of 12 hand muscles was quantified as electromyographic (EMG) muscle activation pattern (MAP) vector and EMG-EMG coherence. We hypothesized that muscle fatigue would cause uniform changes in EMG amplitude across all muscles and an increase in EMG-EMG coherence in the higher frequency bands but with an invariant heterogeneous distribution across muscles. Muscle fatigue caused a 12.5% drop in the maximum voluntary contraction force (P < 0.05) at task failure and an increase in the SD of force (P < 0.01). Although EMG amplitude of all muscles increased during the fatiguing contraction (P < 0.001), the MAP vector orientation did not change, indicating that a similar muscle coordination pattern was used throughout the fatiguing contraction. Last, EMG-EMG coherence (0-35 Hz) was significantly greater at the end than at the beginning of the fatiguing contraction (P < 0.01) but was heterogeneously distributed across hand muscles. These findings suggest that similar mechanisms are involved for modulating and sustaining digit forces in nonfatiguing and fatiguing contractions, respectively.