Spatial variation and inconsistency between estimates of onset of muscle activation from EMG and ultrasound.
Spatial variation and inconsistency between estimates of onset of muscle activation from EMG and ultrasound.
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DOI：
10.1038/srep42011
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发表时间：
2017-02-08
影响因子：
4.6
通讯作者：
Falla D
中科院分区：
文献类型：
--
作者：
Dieterich AV;Botter A;Vieira TM;Peolsson A;Petzke F;Davey P;Falla D
肌肉激活的延迟发作可以是运动控制受损的描述符。激活开始可以从肌电图（EMG）记录的肌肉兴奋和从超声记录的肌肉运动估计，这使得能够在深层肌肉中进行非侵入性测量。然而，在自主激活中，EMG和超声检测到的激活起始可能不对应。为了评估这一点，10名健康男性进行等长屈肘在20%至70%的最大力量。利用超声透明的多通道电极，在肱二头肌上同时记录EMG和M（otion）型超声。自动和视觉估计的激活开始之间的时间间隔与EMG和肌肉运动开始、收缩水平和速度的区域变化相关。自动和视觉发作指示EMG和运动发作之间的可变时间间隔，中位数（四分位距）分别为96（121）ms和48（72）ms。在17%（计算机分析）或23%（视觉分析）的试验中，运动发作在局部EMG发作之前被检测到。多导肌电图和M型超声显示激活起始时间存在区域性差异，随着收缩速度的加快，激活起始时间逐渐减少（斯皮尔曼ρ ≥ 0.45，P < 0.001）。在自愿激活的异质运动单位招聘连同即时运动传输可以解释局部肌电图和超声检测激活发作之间的时间间隔的高变化。
Delayed onset of muscle activation can be a descriptor of impaired motor control. Activation onset can be estimated from electromyography (EMG)-registered muscle excitation and from ultrasound-registered muscle motion, which enables non-invasive measurements in deep muscles. However, in voluntary activation, EMG- and ultrasound-detected activation onsets may not correspond. To evaluate this, ten healthy men performed isometric elbow flexion at 20% to 70% of their maximal force. Utilising a multi-channel electrode transparent to ultrasound, EMG and M(otion)-mode ultrasound were recorded simultaneously over the biceps brachii muscle. The time intervals between automated and visually estimated activation onsets were correlated with the regional variation of EMG and muscle motion onset, contraction level and speed. Automated and visual onsets indicated variable time intervals between EMG- and motion onset, median (interquartile range) 96 (121) ms and 48 (72) ms, respectively. In 17% (computed analysis) or 23% (visual analysis) of trials, motion onset was detected before local EMG onset. Multi-channel EMG and M-mode ultrasound revealed regional differences in activation onset, which decreased with higher contraction speed (Spearman ρ ≥ 0.45, P < 0.001). In voluntary activation the heterogeneous motor unit recruitment together with immediate motion transmission may explain the high variation of the time intervals between local EMG- and ultrasound-detected activation onset.