Structural and control mechanisms for generating force and power from whole muscles

肌肉模型能够准确可靠地评估体内运动功能，在动物和人体研究中经过严格测试，在人类健康和终身活动能力方面具有广泛的应用。最近的肌肉力量产生模型表明，关于整个肌肉在日常活动中如何产生力量，我们还有很多东西要学习。该研究项目的长期目标是将肌肉招募和结构相互作用的复杂机制转化为精细的肌肉模型，从而更准确地预测体内功能。确定促进整个肌肉功能的机制将增强我们研究和维持人类健康和活动的能力。这项工作的结果将直接应用于运动分析过程中肌肉的计算表示，并将被生物力学家、生物医学工程师和卫生专业人员利用。***肌肉纤维的三维路径，它们与周围结缔组织的相互作用以及整个肌肉产生的力都受到纤维在收缩过程中膨胀的方式的影响。我们将调查的因果机制，和后果，横向膨胀的纤维。在日常活动中，每次收缩时只有一小部分肌肉纤维被激活。最近的证据表明，非活性纤维的存在如何影响整个肌肉的收缩特性；我们将测试这是否是由于这种无活性组织的动态特性。肢体的力学取决于肢体中所有肌肉的相互作用和协调。我们将测试在骑车过程中肌肉协调对效率的影响。这项研究计划将通过开发新的工具和技术，以及通过我们新的科学发现，对自然科学和工程产生影响。我们将(1)开发新的基于超声的成像技术，以量化自主收缩期间的三维束状突起；(2)开发和验证收缩肌肉的三维有限元模型，包括实验测量的力和肌肉纤维的内部三维几何形状；(3)开发一个反馈系统，允许肌肉协调实时改变。这些新工具将用于解决有关(A)肌肉结构对整个肌肉功能的影响，(B)非活动组织在整个肌肉中的动态作用，以及(C)与腿部机械输出有关的肌肉协调机制的新的科学问题。＊＊＊＊＊

Muscle models that enable accurate and reliable assessment of in vivo motor function, rigorously tested in animal and human studies, have broad application to human health and life-long mobility. Recent models of muscle force production show that we still have much to learn about how whole muscles generate force during daily activities. The long-term goal of this research program is to translate the complex mechanisms of muscle recruitment and structural interactions into refined muscle models that can predict in vivo function more accurately. Identifying the mechanisms that contribute to whole-muscle function will enhance our ability to study and maintain human health and mobility. The results from this work will have direct application to computational representations of muscles during analysis of movement, and will be utilized by biomechanists, biomedical engineers and health professionals.*** The 3D paths of muscle fibres, their interactions with surrounding connective tissue and the forces produced by the whole muscle are all affected by the way in which the fibres bulge during contraction. We will investigate the causal mechanisms, and the consequences of, the transverse bulging of the fibres. During daily activities, only a fraction of the muscle fibres are activated during each contraction. Recent evidence showed how the presence of inactive fibres affects the contractile properties of whole muscle; we will test whether this is due to the dynamic properties of this inactive tissue. The mechanics of a limb depends on the interaction and coordination of all the muscles in the limb. We will test the effect of muscle coordination on efficiency during cycling. This research program will have an impact on Natural Sciences and Engineering through the development of new tools and technologies, and through our novel scientific findings. We will (1) develop novel ultrasound-based imaging techniques to quantify fascicle bulging in 3D during voluntary contraction, (2) develop and validate 3D finite element models of contracting muscle with both experimentally measured forces, and the internal 3D geometry of the muscle fibres, and (3) develop a feed-back system that allows muscle coordination to be changed in real-time. These new tools will be applied to address novel scientific questions about (A) the effect of muscle structure on whole-muscle function, (B) the role of the dynamics of inactive tissue in the whole muscle, and (C) mechanisms relating muscle coordination to the mechanical output of the leg. *****