Work partitioning of transversally loaded muscle: experimentation and simulation
Work partitioning of transversally loaded muscle: experimentation and simulation
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DOI：
10.1080/10255842.2012.675056
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发表时间：
2014-02
影响因子：
1.6
通讯作者：
T. Siebert;O. Till;R. Blickhan
中科院分区：
文献类型：
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作者：
T. Siebert;O. Till;R. Blickhan
骨骼肌被其他肌肉、结缔组织和骨骼所包围，这可能会将横向力传递到肌肉腹部。简单的hill型肌肉模型不考虑横向力。因此，本研究的目的是检查和模拟横向肌肉负荷对收缩动力学的影响，例如对力发展速度和最大等距肌肉力的影响（film）。对大鼠肌肉进行了横向肌肉负荷和不横向肌肉负荷的等长实验。肌肉通过定制的柱塞加载（1.3 N cm−2），该柱塞能够在横向方向上移动。然后充分刺激肌肉，在远端肌腱处测量等距力，并用高速摄像机捕捉柱塞的运动。肌肉与横向载荷之间的相互作用基于(1)收缩构件（CC）所做的功和(2)提升载荷、拉伸系列弹性结构和变形肌肉所做的功之间的能量平衡来建模。实验和仿真结果表明，与无载荷收缩相比，收缩力速率降低了25%左右，收缩膜减小了5%左右。film的减少是由于使用CC所做的部分工作来提升负载并使肌肉变形。肌肉对横向载荷的响应打开了一个窗口，了解收缩和变形工作的相互依赖性，可用于指定和验证3D肌肉模型。
Skeletal muscles are surrounded by other muscles, connective tissue and bones, which may transfer transversal forces to the muscle belly. Simple Hill-type muscle models do not consider transversal forces. Thus, the aim of this study was to examine and model the influence of transversal muscle loading on contraction dynamics, e.g. on the rate of force development and on the maximum isometric muscle force (Fim). Isometric experiments with and without transversal muscle loading were conducted on rat muscles. The muscles were loaded (1.3 N cm− 2) by a custom-made plunger which was able to move in transversal direction. Then the muscle was fully stimulated, the isometric force was measured at the distal tendon and the movement of the plunger was captured with a high-speed camera. The interaction between the muscle and the transversal load was modelled based on energy balance between the (1) work done by the contractile component (CC) and (2) the work done to lift the load, to stretch the series elastic structures and to deform the muscle. Compared with the unloaded contraction, the force rate was reduced by about 25% and Fim was reduced by 5% both in the experiment and in the simulation. The reduction in Fim resulted from using part of the work done by the CC to lift the load and deform the muscle. The response of the muscle to transversal loading opens a window into the interdependence of contractile and deformation work, which can be used to specify and validate 3D muscle models.