Ruan Mianfang, Li Li, Zhu Weiping, Huang Tianchen, Wu Xie
Sports Biomechanics Laboratory, College of Physical Education and Health, Wenzhou University, Wenzhou, China.
Department of Health Sciences and Kinesiology, Georgia Southern University, Statesboro, GA, United States.
Front Physiol. 2021 Mar 9;12:623126. doi: 10.3389/fphys.2021.623126. eCollection 2021.
A novel device has been developed to assess eccentric hamstring strength during the Nordic hamstring exercise (NHE) by measuring the contact force at the ankle hook (brace). The purpose of this study was to determine the correlation between the force measured at the ankle hook and the hamstring force estimated by a low extremity model. Thirteen male college sprinters were recruited to perform NHE on an instrumented device Nordbord (Vald Performance, Australia). Contact forces were measured at a sampling rate of 50 Hz at the hooks using the uniaxial load cells. 3D kinematics were measured simultaneously at a sampling rate of 200 Hz using a 16-camera motion analysis system (Vicon Motion Analysis, Oxford, United Kingdom) during the NHE. The data were processed with Visual 3D (C-Motion, Germantown, MD, United States) and OpenSim (NCSRR, Stanford, CA, United States) to calculate the knee joint center's coordinates and hamstring moment arms during NHE. A static low extremity model was built to estimate the hamstring force during NHE. We have observed a significant but not very high correlation ( = 0.58) between peak hamstring force and the peak contact force at the ankle hook. The peak contact force measured at the ankle hook can only explain a little more than half of the variations in peak hamstring muscle forces during NHE. Caution must be exercised when assessing the eccentric hamstring strength using the ankle contact force during NHE.
一种新型装置已被开发出来，通过测量脚踝挂钩（护具）处的接触力来评估北欧式腿弯举运动（NHE）期间的股后肌群离心力量。本研究的目的是确定在脚踝挂钩处测量的力与通过下肢模型估计的股后肌群力量之间的相关性。招募了13名男性大学短跑运动员，让他们在仪器化设备Nordbord（澳大利亚Vald Performance公司）上进行NHE。使用单轴测力传感器以50Hz的采样率在挂钩处测量接触力。在NHE期间，使用16台摄像机的运动分析系统（英国牛津Vicon运动分析公司）以200Hz的采样率同时测量三维运动学数据。使用Visual 3D（美国马里兰州日耳曼敦C-Motion公司）和OpenSim（美国加利福尼亚州斯坦福NCSRR公司）对数据进行处理，以计算NHE期间膝关节中心的坐标和股后肌群的力臂。建立了一个静态下肢模型来估计NHE期间的股后肌群力量。我们观察到股后肌群峰值力量与脚踝挂钩处的峰值接触力之间存在显著但不是非常高的相关性（r = 0.58）。在脚踝挂钩处测量的峰值接触力只能解释NHE期间股后肌群峰值力量变化的一半多一点。在使用NHE期间的脚踝接触力评估股后肌群离心力量时必须谨慎。
