University of Nebraska-Lincoln, Lincoln, NE, United States of America.
Physiol Meas. 2017 Sep 21;38(10):1837-1847. doi: 10.1088/1361-6579/aa8983.
To examine muscle-specific differences and the effects of fatigue and recovery on electromechanical delay (EMD) during maximal isokinetic muscle actions.
Thirteen men performed maximal isokinetic knee extension muscle actions at 60° s, pretest, posttest, and after 5 min of recovery from 25 maximal isokinetic knee extensions. The onsets of the electromyographic, mechanomyographic, and force signals were used to identify EMD measures from the vastus lateralis (VL), vastus medialis (VM), and rectus femoris (RF).
There were posttest increases in all EMD measures for all muscles that returned to pretest levels after 5 min of recovery. There were, however, no differences in EMD measures between the VL and VM. All EMD values from the RF were greater than the VL and VM.
These findings suggested muscle-specific differences in EMD and that excitation-contraction coupling failure and increased compliance of the series elastic component occurred posttest, but subsided after 5 min of recovery.
研究在最大等速肌肉活动期间，肌特异性差异以及疲劳和恢复对机电延迟（EMD）的影响。
13 名男性以 60°/s 的速度进行最大等速膝关节伸展肌肉活动，在预测试、后测试以及 25 次最大等速膝关节伸展后 5 分钟的恢复后进行。肌电图、肌动图和力信号的起始用于从股外侧肌（VL）、股中间肌（VM）和股直肌（RF）中识别 EMD 测量值。
所有肌肉的 EMD 测量值在后测试中均增加，在 5 分钟的恢复后恢复到预测试水平。然而，VL 和 VM 之间的 EMD 测量值没有差异。RF 的所有 EMD 值均大于 VL 和 VM。
这些发现表明 EMD 存在肌特异性差异，并且兴奋-收缩耦联失败和串联弹性组件的顺应性增加在后测试中发生，但在 5 分钟的恢复后消退。
