Modulation of leg muscle function in response to altered demand for body support and forward propulsion during walking
Modulation of leg muscle function in response to altered demand for body support and forward propulsion during walking
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DOI：
10.1016/j.jbiomech.2009.01.025
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发表时间：
2009-05-11
影响因子：
2.4
通讯作者：
Neptune, R. R.
中科院分区：
文献类型：
--
作者：
McGowan, C. P.;Kram, R.;Neptune, R. R.
许多研究已经检查了正常行走过程中单个肌肉的功能作用，但很少有研究检查哪些是响应外部机械需求变化的主要肌肉。在这里，我们使用一种新的实验扰动和正向动力学模拟相结合，以确定如何肌肉机械输出和贡献身体的支持和向前推进调制在行走过程中的体重和体重的独立操作。通过增加躯干负荷和体重支撑的组合，产生实验性改变的重量和/或质量。相同的实验条件下的模拟被用来确定肌肉贡献的垂直地面反作用力脉冲（身体支撑）和积极的水平躯干工作（向前推进）。比目鱼肌，vastii和臀大肌的垂直冲动的贡献增加（减少），在体重的增加（减少），而只有比目鱼肌增加水平的工作输出响应增加体重。此外，比目鱼肌对垂直冲量和水平躯干功的绝对贡献最大，这表明比目鱼肌不仅对身体支撑和向前推进力的贡献最大，而且比目鱼肌也是调节腿部机械输出的主要机制，以响应对身体支撑和向前推进力的增加（减少）需求。数据还表明，肌肉对特定任务的贡献可能与其对其他任务的贡献无关（例如，身体支撑与向前推进）。(C)2009爱思唯尔有限公司保留所有权利。
A number of studies have examined the functional roles of individual muscles during normal walking, but few studies have examined which are the primary muscles that respond to changes in external mechanical demand. Here we use a novel combination of experimental perturbations and forward dynamics simulations to determine how muscle mechanical output and contributions to body support and forward propulsion are modulated in response to independent manipulations of body weight and body mass during walking. Experimentally altered weight and/or mass were produced by combinations of added trunk loads and body weight support. Simulations of the same experimental conditions were used to determine muscle contributions to the vertical ground reaction force impulse (body support) and positive horizontal trunk work (forward propulsion). Contributions to the vertical impulse by the soleus, vastii and gluteus maximus increased (decreased) in response to increases (decreases) in body weight; whereas only the soleus increased horizontal work output in response to increased body mass. In addition, soleus had the greatest absolute contribution to both vertical impulse and horizontal trunk work, indicating that it not only provides the largest contribution to both body support and forward propulsion, but the soleus is also the primary mechanism to modulate the mechanical output of the leg in response to increased (decreased) need for body support and forward propulsion. The data also showed that a muscle's contribution to a specific task is likely not independent of its contribution to other tasks (e.g., body support vs. forward propulsion). (C) 2009 Elsevier Ltd. All rights reserved.