疲劳对腓肠肌内侧肌机电延迟成分的影响。
Effects of fatigue on the electromechanical delay components in gastrocnemius medialis muscle.
机构信息
Department of Biomedical Sciences for Health, University of Milan, Via G. Colombo 71, 20133, Milan, Italy.
出版信息
Eur J Appl Physiol. 2014 Mar;114(3):639-51. doi: 10.1007/s00421-013-2790-9. Epub 2013 Dec 21.
PURPOSE
Under electrically evoked contractions, the time interval between the onset of the stimulation pulse (Stim) and the beginning of force (F) development can be partitioned (Delay(TOT)), by an electromyographic (EMG), mechanomyographic (MMG) and F combined approach, into three components each containing different parts of the electrochemical and mechanical processes underlying neuromuscular activation and contraction. The aim of the study was to evaluate inter- and intra-operator reliability of the measurements and to assess the effects of fatigue on the different Delay(TOT) components.
METHODS
Sixteen participants underwent two sets of tetanic stimulations of the gastrocnemius medialis muscle, with 10 min of rest in between. After a fatiguing protocol of 120 s, tetanic stimulations were replicated. The same protocol was repeated on a different day. Stim, EMG, MMG and F signals were recorded during contraction. Delay(TOT) and its three components (between Stim and EMG, Δt Stim-EMG; between EMG and MMG, Δt EMG-MMG and between MMG and F, Δt MMG-F) were calculated.
RESULTS
Before fatigue, Delay(TOT), Δt Stim-EMG, Δt EMG-MMG and Δt MMG-F lasted 27.5 ± 0.9, 1.4 ± 0.1, 9.2 ± 0.5 and 16.8 ± 0.7 ms, respectively. Fatigue lengthened Delay(TOT), Δt Stim-EMG, Δt EMG-MMG and Δt MMG-F by 18, 7, 16 and 22 %, respectively. Δt Stim-EMG, Δt EMG-MMG and Δt MMG-F contributed to Delay(TOT) lengthening by 2, 27 and 71 %, respectively. Reliability was always from high to very high.
CONCLUSIONS
The combined approach allowed a reliable calculation of the three contributors to Delay(TOT). The effects of fatigue on each Delay(TOT) component could be precisely assessed.
目的
在电诱发收缩过程中，可以通过肌电图（EMG）、机械肌电图（MMG）和 F 的联合方法，将刺激脉冲（Stim）起始和力（F）发展之间的时间间隔（Delay(TOT))）分为三个组成部分，每个组成部分包含神经肌肉激活和收缩的电化学和机械过程的不同部分。本研究的目的是评估测量的组内和组间可靠性，并评估疲劳对不同 Delay(TOT) 成分的影响。
方法
16 名参与者接受了内侧比目鱼肌的两次强直刺激，两次之间休息 10 分钟。疲劳方案 120 秒后，重复强直刺激。在不同的一天重复相同的方案。在收缩过程中记录 Stim、EMG、MMG 和 F 信号。计算 Delay(TOT)及其三个组成部分（Stim 和 EMG 之间的 Delay(TOT)，Δt Stim-EMG；EMG 和 MMG 之间的 Delay(TOT)，Δt EMG-MMG 和 MMG 和 F 之间的 Delay(TOT)，Δt MMG-F）。
结果
在疲劳之前，Delay(TOT)、Δt Stim-EMG、Δt EMG-MMG 和 Δt MMG-F 分别持续 27.5±0.9、1.4±0.1、9.2±0.5 和 16.8±0.7 ms。疲劳使 Delay(TOT)、Δt Stim-EMG、Δt EMG-MMG 和 Δt MMG-F 分别延长了 18%、7%、16%和 22%。Δt Stim-EMG、Δt EMG-MMG 和 Δt MMG-F 分别占 Delay(TOT)延长的 2%、27%和 71%。可靠性始终从高到非常高。
结论
联合方法允许可靠地计算 Delay(TOT)的三个组成部分。可以精确评估疲劳对每个 Delay(TOT)成分的影响。
Zotero 插件