持续等长肌肉动作期间神经肌肉参数变化的时间进程
Time Course of Changes in Neuromuscular Parameters During Sustained Isometric Muscle Actions.
作者信息
Smith Cory M, Housh Terry J, Herda Trent J, Zuniga Jorge M, Camic Clayton L, Bergstrom Haley C, Smith Doug B, Weir Joseph P, Hill Ethan C, Cochrane Kristen C, Jenkins Nathaniel D M, Schmidt Richard J, Johnson Glen O
机构信息
1Department of Nutrition and Health Science, University of Nebraska-Lincoln, Lincoln, Nebraska;2Department of Health, Sport, and Exercise Sciences, University of Kansas, Lawrence, Kansas;3Department of Exercise Science & Pre-Health Professions, Creighton University, Omaha, Nebraska;4Department of Exercise & Sport Science, University of Wisconsin-La Crosse, La Crosse, Wisconsin;5Department of Kinesiology & Health Promotion, University of Kentucky, Lexington, Kentucky; and6Department of Health and Human Performance, Oklahoma State University-Stillwater, Stillwater, Oklahoma.
出版信息
J Strength Cond Res. 2016 Oct;30(10):2697-2702. doi: 10.1519/JSC.0000000000001547.
Smith, CM, Housh, TJ, Herda, TJ, Zuniga, JM, Camic, CL, Bergstrom, HC, Smith, DB, Weir, JP, Hill, EC, Cochrane, KC, Jenkins, NDM, Schmidt, RJ, and Johnson, GO. Time course of changes in neuromuscular parameters during sustained isometric muscle actions. J Strength Cond Res 30(10): 2697-2702, 2016-The objective of the present study was to identify the time course of changes in electromyographic (EMG) and mechanomyographic (MMG) time and frequency domain parameters during a sustained isometric muscle action of the leg extensors at 50% maximal voluntary isometric contraction. The EMG and MMG signals were measured from the vastus lateralis of 11 subjects to identify when motor unit activation strategies changed throughout the sustained isometric muscle action. The EMG amplitude (muscle activation) had a positive linear relationship (p = 0.018, r = 0.77) that began to increase at the initiation of the muscle action and continued until task failure. Electromyographic frequency (motor unit action potential conduction velocity) and MMG frequency (global motor unit firing rate) had negative quadratic relationships (p = 0.002, R = 0.99; p = 0.015, R = 0.94) that began to decrease at 30% of the time to exhaustion. The MMG amplitude (motor unit activation) had a cubic relationship (p = 0.001, R = 0.94) that increased from 10 to 30% of the time to exhaustion, then decreased from 40 to 70% of the time to exhaustion, and then markedly increased from 70% to task failure. The time course of changes in the neuromuscular parameters suggested that motor unit activation strategies changed at approximately 30 and 70% of the time to exhaustion during the sustained isometric muscle action. These findings indicate that the time course of changes in neuromuscular responses provide insight into the strategies used to delay the effects of fatigue and are valuable tools for quantifying changes in the fatiguing process during training programs or supplementation research.
史密斯，CM；豪什，TJ；赫达，TJ；祖尼加，JM；卡米克，CL；伯格斯特龙，HC；史密斯，DB；韦尔，JP；希尔，EC；科克伦，KC；詹金斯，NDM；施密特，RJ；约翰逊，GO。持续等长肌肉动作期间神经肌肉参数变化的时间进程。《力量与体能研究杂志》30(10): 2697 - 2702，2016年——本研究的目的是确定在腿部伸肌以50%最大自主等长收缩进行持续等长肌肉动作期间，肌电图（EMG）和机械肌电图（MMG）的时间和频域参数变化的时间进程。从11名受试者的股外侧肌测量EMG和MMG信号，以确定在整个持续等长肌肉动作过程中运动单位激活策略何时发生变化。EMG幅度（肌肉激活）呈正线性关系（p = 0.018，r = 0.77），在肌肉动作开始时开始增加，并持续到任务失败。肌电图频率（运动单位动作电位传导速度）和MMG频率（整体运动单位放电率）呈负二次关系（p = 0.002，R = 0.99；p = 0.015，R = 0.94），在疲劳时间的30%时开始下降。MMG幅度（运动单位激活）呈三次关系（p = 0.001，R = 0.94），从疲劳时间的10%增加到30%，然后从40%下降到70%，然后从70%到任务失败时显著增加。神经肌肉参数变化的时间进程表明，在持续等长肌肉动作期间，运动单位激活策略在疲劳时间的大约30%和70%时发生变化。这些发现表明，神经肌肉反应变化的时间进程有助于深入了解用于延迟疲劳影响的策略，并且是量化训练计划或补充研究期间疲劳过程变化的有价值工具。
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