How robust is human gait to muscle weakness?
How robust is human gait to muscle weakness?
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DOI：
10.1016/j.gaitpost.2012.01.017
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发表时间：
2012-05
期刊：
影响因子：
2.4
通讯作者：
Schwartz MH
中科院分区：
文献类型：
--
作者：
van der Krogt MM;Delp SL;Schwartz MH
人类具有非凡的能力来完成需要敏捷、时机和力量的复杂动作。废用、衰老和疾病会导致肌肉力量的丧失，这通常会限制运动任务的表现。然而，在正常的日常活动受到损害之前，我们还不知道可以忍受多少虚弱。这项研究探讨了在正常行走受到影响之前，下肢肌肉可以被削弱的程度。我们开发了肌肉驱动的正常行走模拟，然后逐步削弱所有主要肌肉群，一次一个，同时，以评估在执行正常步态变得不可能之前，可以忍受多少虚弱。我们进一步研究了由于肌肉减弱而产生的补偿。我们的模拟显示，正常行走对某些肌肉的弱点非常强大，但对其他肌肉的弱点很敏感。步态在髋关节和膝关节伸肌无力时表现得最稳健，因为它们可以很好地忍受无力，而不会大幅增加肌肉应力。相反，步态对跖屈肌、髋外展肌和髋屈肌的虚弱最为敏感。个别肌肉的虚弱导致虚弱肌肉的激活增加，以及其他肌肉的补偿激活。这些补偿通常是低效的，并产生不平衡的关节力矩，需要在其他肌肉中进行补偿激活。因此，总的肌肉激活随着虚弱而增加，步行的代价也是如此。通过澄清哪些肌肉对维持正常步态至关重要，我们的研究结果为开发预防或改善步态病理的疗法提供了重要的见解。
Humans have a remarkable capacity to perform complex movements requiring agility, timing, and strength. Disuse, aging, and disease can lead to a loss of muscle strength, which frequently limits the performance of motor tasks. It is unknown, however, how much weakness can be tolerated before normal daily activities become impaired. This study examines the extent to which lower limb muscles can be weakened before normal walking is affected. We developed muscle-driven simulations of normal walking and then progressively weakened all major muscle groups, one at the time and simultaneously, to evaluate how much weakness could be tolerated before execution of normal gait became impossible. We further examined the compensations that arose as a result of weakening muscles. Our simulations revealed that normal walking is remarkably robust to weakness of some muscles but sensitive to weakness of others. Gait appears most robust to weakness of hip and knee extensors, which can tolerate weakness well and without a substantial increase in muscle stress. In contrast, gait is most sensitive to weakness of plantarflexors, hip abductors, and hip flexors. Weakness of individual muscles results in increased activation of the weak muscle, and in compensatory activation of other muscles. These compensations are generally inefficient, and generate unbalanced joint moments that require compensatory activation in yet other muscles. As a result, total muscle activation increases with weakness as does the cost of walking. By clarifying which muscles are critical to maintaining normal gait, our results provide important insights for developing therapies to prevent or improve gait pathology.