Universite Claude Bernard Lyon 1, Laboratoire Interuniversitaire de Biologie de la Motricité (LIBM), F-69622 Villeurbanne, France.
University of Lausanne, Lausanne University Hospital, Department of Diagnostic and Interventional Radiology, Lausanne, Switzerland.
J Electromyogr Kinesiol. 2023 Dec;73:102826. doi: 10.1016/j.jelekin.2023.102826. Epub 2023 Sep 21.
The use of shear wave elastography during voluntary contraction has enabled the non-invasive assessment of load sharing strategies between agonist muscles. However, the change in joint angle and voluntary contraction intensity can modify contribution between muscles. The aim of this study was to investigate the effect of knee joint angle on the local mechanical properties of the vastus medialis (VM) and the vastus lateralis (VL) during isometric submaximal voluntary contractions from shear wave elastography mapping. The VM and VL Young's modulus at rest and during constant isometric submaximal voluntary contractions (i.e., 25%, 50% and 75% of maximal voluntary contraction [MVC]) were assessed for two knee angles (50° and 100° | knee fully extended = 0°) in twelve participants. No significant difference was found in the VM Young's modulus among all torque levels and knee angles (p > 0.05). VL Young's modulus was significantly higher at 25% MVC for a knee angle of 100° than at 75% MVC for the same knee angle and was greater at 25% MVC for a knee angle of 100° than for 50° (p < 0.05). In contrast to the VM, the contribution of the VL to the knee joint torque production during isometric voluntary contraction appears to depend on the muscle length and the relative knee extension torque level.
在主动收缩期间使用剪切波弹性成像技术使得能够对作用肌之间的负荷分担策略进行非侵入性评估。然而，关节角度和主动收缩强度的变化会改变肌肉之间的贡献。本研究旨在从剪切波弹性成像图谱中调查膝关节角度对等长亚最大自愿收缩期间股直肌（VM）和股外侧肌（VL）局部力学特性的影响。在 12 名参与者中，评估了两种膝关节角度（50°和 100°|膝关节完全伸展= 0°）下静息和等长亚最大自愿收缩（即最大自愿收缩[MVC]的 25%、50%和 75%）期间 VM 和 VL 的杨氏模量。在所有扭矩水平和膝关节角度下，VM 的杨氏模量均无显着差异（p> 0.05）。与相同膝关节角度的 75% MVC 相比，膝关节角度为 100°时，VL 的杨氏模量在 25% MVC 时显着更高，而膝关节角度为 100°时比 50°时更高（p<0.05）。与 VM 相反，VL 对等长自愿收缩期间膝关节扭矩产生的贡献似乎取决于肌肉长度和相对膝关节伸展扭矩水平。
