Acute passive stretching in a previously fatigued muscle: Electrical and mechanical response during tetanic stimulation
Acute passive stretching in a previously fatigued muscle: Electrical and mechanical response during tetanic stimulation
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DOI：
10.1080/02640410903165093
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发表时间：
2009-01-01
影响因子：
3.4
通讯作者：
Veicsteinas, Arsenio
中科院分区：
文献类型：
--
作者：
Esposito, Fabio;Ce, Emiliano;Veicsteinas, Arsenio
本研究的目的是评估急性被动拉伸对先前疲劳肌肉的电和机械反应的影响。11名参与者在疲劳方案之前和之后以及疲劳肌肉被动拉伸之后对腓肠肌内侧进行了最大的强直刺激（50 Hz）。在收缩过程中，记录表面肌电图（EMG）、肌力图（MMG）和肌力。计算如下参数：(1)肌电图均方根（RMS）、平均频率、纤维传导速度；(2) MMG峰间和均方根；(3)峰值力、收缩时间、半松弛时间、峰值力发展速率（dF/dt）及其加速度(d（2)F/dt(2)）。疲劳使峰值力降低18% (P < 0.05)，并影响其他力、肌电和MMG参数。拉伸后：(1)所有肌电参数恢复到疲劳前值；(2) MMG峰间值持续下降，RMS恢复到疲劳前值；(3)峰值力、峰值力发展速率及其加速度分别比对照组减少22.2%、18%和51%，半松弛时间比对照组减少40% （P < 0.05）。总之，急性被动拉伸，当应用于先前疲劳的肌肉时，进一步降低了最大发力能力。虽然拉伸不会改变疲劳肌肉的电参数，但它确实会影响肌肉-肌腱单元的机械行为。
The aim of this study was to assess the effects of acute passive stretching on the electrical and mechanical response of a previously fatigued muscle. Eleven participants underwent maximal tetanic stimulations (50 Hz) of the medial gastrocnemius, before and after a fatiguing protocol and after a bout of passive stretching of the fatigued muscle. During contraction, surface electromyography (EMG), mechanomyography (MMG), and force were recorded. The following parameters were calculated: (1) the EMG root mean square (RMS), mean frequency, and fibre conduction velocity; (2) MMG peak-to-peak and RMS; (3) the peak force, contraction time, half-relaxation time, peak rate of force development (dF/dt) and its acceleration (d(2)F/dt(2)). Fatigue reduced peak force by 18% (P < 0.05) and affected the other force, EMG, and MMG parameters. After stretching: (1) all EMG parameters recovered to pre-fatigue values; (2) MMG peak-to-peak remained depressed, while RMS recovered to pre-fatigue values; (3) the peak force, peak rate of force development and its acceleration were further reduced by 22, 18, and 51%, respectively, and half-relaxation time by 40% (P < 0.05). In conclusion, acute passive stretching, when applied to a previously fatigued muscle, further depresses the maximum force-generating capacity. Although stretching does not alter the electrical parameters of the fatigued muscle, it does affect the mechanical behaviour of the muscle-tendon unit.