Measurement of muscle stiffness based on a vibro-ultrasound method

Abstract

现有的各种研究肌肉硬度的方法有其各 自的优点和局限性。在过去的此类研究中,很少使用肌肉最大自主收缩(Maximum Voluntary Contraction,MVC)扭矩的百分比来表达相对收缩水平,而且缺少高收缩水平(40%MVC以上)下测量肌肉硬度的手段。本文采用了一种基于振 动-超声法测量剪切波波速,继而计算肌肉剪切模量的新方法,解决了高收缩水平下肌肉硬度的测量问题。我们以右腿股中间肌为目标,测量了从 0%～100%MVC共11个不同等长收缩水平下的肌肉剪切模量。两组年轻的健康男性和女性受试者(各10名)自愿参加了本次研究。研究结果表明,股中间 肌沿肌纤维方向的剪切模量,与肌肉的相对收缩水平正相关,它们之间的拟合结果接近二次多项式关系。在相同的相对收缩水平下,男性的肌肉硬度大于女性。 Existing methods for muscle stiffness measurement have their unique features and limitations in in vivo studies.Few studies have been reported to evaluate the muscle stiffness at the higher percentage of maximum voluntary contraction levels (>40% MVC).In this study,using a newly developed vibro-ultrasound method,we assessed the shear modulus of vastus intermedius from 0% to 100% MVC.Ten young healthy male subjects and ten young healthy female subjects volunteered to participate.Our results demonstrated that the stiffness of vastus intermedius in the direction along the muscle fibers is positively correlated with the isometric contraction levels at both joint angles and there is a quadratic relationship between them.At the same contraction level,the muscle shear modulus of males was larger than that of females.