Resting shear elastic modulus as a marker of peripheral fatigue during maximal isometric contractions in humans.xlsx

The aim of this study was to investigate whether the resting Vastus Lateralis (VL) muscle shear elastic modulus (µ), evaluated by shear wave elastography, represents peripheral fatigue during repetition of isometric maximal voluntary contractions (MVCs) of the knee extensor (KE) muscles.<br> Eight healthy well-trained males volunteered to repeated 60 isometric MVCs of the KE muscles (6 × 10 MVCs; 5 s on/5 s off). Single and double electrical stimulations were delivered to the femoral nerve every ten MVCs during contraction and at rest. The amplitude and properties of the potentiated torque following single (Twpot) double electrostimulation and the amplitude of the concomitant VL compound action potential were considered to be indicators of peripheral fatigue. The resting VLµ was measured during a 5-s rest period after each MVC and electrical stimulation series.<br><br>

本研究旨在探讨通过剪切波弹性成像（shear wave elastography）评估的静息股外侧肌（Vastus Lateralis，VL）剪切弹性模量（µ）是否可反映膝伸肌（knee extensor，KE）重复进行等长最大自主收缩（isometric maximal voluntary contractions，MVCs）过程中的外周疲劳。
8名健康且训练有素的男性志愿者自愿完成60次膝伸肌等长最大自主收缩（分为6组，每组10次，收缩5秒/休息5秒）。在每10次最大自主收缩完成后的收缩阶段与静息状态下，对股神经（femoral nerve）施加单次与双次电刺激。将单次电刺激后的增强扭矩（Twpot）、双次电刺激后增强扭矩的幅值与特性，以及伴随的股外侧肌复合动作电位的幅值作为外周疲劳的评价指标。在每次最大自主收缩及电刺激序列结束后的5秒静息期内，测量静息状态下的股外侧肌剪切弹性模量。