Contribution of muscle short-range stiffness to initial changes in joint kinetics and kinematics during perturbations to standing balance: A simulation study.
Contribution of muscle short-range stiffness to initial changes in joint kinetics and kinematics during perturbations to standing balance: A simulation study.
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DOI：
10.1016/j.jbiomech.2017.02.008
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发表时间：
2017-04-11
影响因子：
2.4
通讯作者：
Ting LH
中科院分区：
文献类型：
--
作者：
De Groote F;Allen JL;Ting LH
模拟真实的肌肉骨骼动力学对于理解在具有固有神经传递延迟的感觉运动反馈反应中引起的肌肉活动的神经控制至关重要。因此，在没有任何肌肉活动变化的情况下，肌肉对扰动的初始机械反应决定了稳定身体姿势所需的纠正性神经反应。肌肉短距离僵硬是肌肉的一种依赖历史的特性，在拉伸时引起肌肉力的快速和短暂的上升，可能影响对扰动的初始机械响应中的肌肉骨骼动力学。在这里，我们分别使用动态模拟确定了在支撑面平移的初始机械响应中，短期刚度对关节扭矩和角度的贡献。我们开发了一个肌肉近程刚度的动态模型来增强hill型肌肉模型。我们的模拟表明，在神经力学响应延迟期间，短程刚度可以提供对外部扰动的稳定性。假设在初始机械响应过程中肌肉持续激活，包括肌肉短距离刚度，可以解释实验中膝关节和髋关节矢状面扭矩的快速上升，同时关节角度变化很小，模拟扭矩和实验扭矩之间的均方根误差分别降低了56%和47%。此外，缺乏短距离刚度的正演模拟在初始响应过程中产生了不合理的大关节角变化。基于神经控制和生物力学原理，使用肌肉模型来计算短距离僵硬以及其他依赖历史的肌肉动力学方面，对于提高我们模拟固有不稳定的人类运动的能力可能很重要。
Simulating realistic musculoskeletal dynamics is critical to understanding neural control of muscle activity evoked in sensorimotor feedback responses that have inherent neural transmission delays. Thus, the initial mechanical response of muscles to perturbations in the absence of any change in muscle activity determines which corrective neural responses are required to stabilize body posture. Muscle short-range stiffness, a history-dependent property of muscle that causes a rapid and transient rise in muscle force upon stretch, likely affects musculoskeletal dynamics in the initial mechanical response to perturbations. Here we identified the contributions of short-range stiffness to joint torques and angles in the initial mechanical response to support surface translations using dynamic simulation, respectively. We developed a dynamic model of muscle short-range stiffness to augment a Hill-type muscle model. Our simulations show that short-range stiffness can provide stability against external perturbations during the neuromechanical response delay. Assuming constant muscle activation during the initial mechanical response, including muscle short-range stiffness was necessary to account for the rapid rise in experimental sagittal plane knee and hip joint torques that occurs simultaneously with very small changes in joint angles and reduced root mean square errors between simulated and experimental torques by 56% and 47%, respectively. Moreover, forward simulations lacking short-range stiffness produced unreasonably large joint angle changes during the initial response. Using muscle models accounting for short-range stiffness along with other aspects of history-dependent muscle dynamics may be important to advance our ability to simulate inherently unstable human movements based on principles of neural control and biomechanics.