Blemker Silvia S, Pinsky Peter M, Delp Scott L
Department of Mechanical Engineering, Stanford University, Stanford, CA 94305-5450, USA.
J Biomech. 2005 Apr;38(4):657-65. doi: 10.1016/j.jbiomech.2004.04.009.
Biomechanical models generally assume that muscle fascicles shorten uniformly. However, dynamic magnetic resonance (MR) images of the biceps brachii have recently shown nonuniform shortening along some muscle fascicles during low-load elbow flexion (J. Appl. Physiol. 92 (2002) 2381). The purpose of this study was to uncover the features of the biceps brachii architecture and material properties that could lead to nonuniform shortening. We created a three-dimensional finite-element model of the biceps brachii and compared the tissue strains predicted by the model with experimentally measured tissue strains. The finite-element model predicted strains that were within one standard deviation of the experimentally measured strains. Analysis of the model revealed that the variation in fascicle lengths within the muscle and the curvature of the fascicles were the primary factors contributing to nonuniform strains. Continuum representations of muscle, combined with in vivo image data, are needed to deepen our understanding of how complex geometric arrangements of muscle fibers affect muscle contraction mechanics.
生物力学模型通常假定肌肉束均匀缩短。然而，肱二头肌的动态磁共振（MR）图像最近显示，在低负荷屈肘过程中，一些肌肉束存在不均匀缩短（《应用生理学杂志》92卷（2002年）第2381页）。本研究的目的是揭示可能导致不均匀缩短的肱二头肌结构和材料特性。我们创建了肱二头肌的三维有限元模型，并将模型预测的组织应变与实验测量的组织应变进行比较。有限元模型预测的应变在实验测量应变的一个标准差范围内。对模型的分析表明，肌肉内肌束长度的变化和肌束的曲率是导致应变不均匀的主要因素。需要结合体内图像数据的肌肉连续体表示，以加深我们对肌肉纤维复杂几何排列如何影响肌肉收缩力学的理解。
