Muscle mechanical work requirements during normal walking: the energetic cost of raising the body's center-of-mass is significant
Muscle mechanical work requirements during normal walking: the energetic cost of raising the body's center-of-mass is significant
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DOI：
10.1016/j.jbiomech.2003.11.001
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发表时间：
2004-06-01
影响因子：
2.4
通讯作者：
Kautz, SA
中科院分区：
文献类型：
--
作者：
Neptune, RR;Zajac, FE;Kautz, SA
步行的倒立摆模型预测，交换身体势能和单肢支撑动能只需要很少的肌肉工作。通常分析步行期间的外部功率（测量的地面反作用力和身体质心（COM）速度的乘积）以推断肌肉的净功输出或机械能量成本。基于外部功率分析和倒立摆理论，有人提出，主要的机械能量成本可能与在逐步过渡时重定向 COM 运动所需的机械功相关。然而，这些模型没有捕捉步行的多肌肉、多节段特性、肌肉的共兴奋以协调节段能量流以及同时产生正负肌肉功。在本研究中，使用肌驱动的向前动态模拟步行来评估是否：（1）身体的势能和动能在很少的肌肉工作下进行交换； (2)外部机械功率可以估计肌肉的机械能量成本，(3)肌肉的净功输出和机械能量成本大多发生在双支撑中。我们发现，肌肉的净功输出无法通过外部功率来估计，并且当 COM 在早期单肢支撑中向上移动时，即使动能和势能交换，肌肉的净功输出也最高，并且肌肉机械（最有可能是代谢）能量消耗不仅取决于在双支撑中重定向 COM 的需要，而且还取决于在单肢支撑中升高 COM 的需要。 (C) 2003 Elsevier Ltd. 保留所有权利。
Inverted pendulum models of walking predict that little muscle work is required for the exchange of body potential and kinetic energy single-limb Support. External power during walking (product of the measured ground reaction force and body center-of-mass (COM) velocity) is often analyzed to deduce net work Output or mechanical energetic cost by muscles. Based on external power analyses and inverted pendulum theory, it has been suggested that a primary mechanical energetic cost may be associated with the mechanical work required to redirect the COM motion at the step-to-step transition. However, these models do not capture the multi-muscle, multi-segmental properties of walking, co-excitation Of muscles to coordinate segmental energetic flow, and simultaneous production of positive and negative muscle work. In this Study, a inuscle-actuated forward dynamic simulation of walking was used to assess whether: (1) potential and kinetic energy of the body are exchanged with little muscle work; (2) external mechanical power can estimate the mechanical energetic cost for muscles, and (3) the net work output and the mechanical energetic cost for muscles occurs mostly in double support. We found that the net work output by muscles cannot be estimated from external power and was the highest when the COM moved upward in early single-limb support even though kinetic and potential energy were exchanged, and Muscle mechanical (and most likely metabolic) energetic cost is dominated not only by the need to redirect the COM in double support but also by the need to raise the COM in single support. (C) 2003 Elsevier Ltd. All rights reserved.