Biomechanical Causes of Slow Gait in the Elderly

描述（由申请人提供）：本研究的目的是为制定有针对性的干预措施，改善老年人的步态功能奠定科学基础。步行速度是临床常用的衡量步态功能的指标。缓慢的首选步行速度与跌倒有关，可能导致身体残疾，并且是用于描述虚弱临床综合征的主要标准之一。力量的减少和有氧能力的减弱通常被认为是缓慢行走的原因。体弱的老年人通常可以通过锻炼显著提高肌肉力量和耐力。然而，这些收益并没有始终转化为步态性能的改善。这些发现表明步态表现的复杂性，并表明需要对限制步态速度的神经肌肉因素有更基本的了解。

DESCRIPTION (provided by applicant): The goal of this research is to establish a scientific basis for developing targeted interventions that can improve gait function in the elderly. Walking speed is a common clinical measure of gait function. Slow preferred walking speed has been associated with falls, can contribute to physical disability and is one of the primary criteria used to describe the clinical syndrome of frailty. Reduced strength and diminished aerobic capacity are commonly proposed causes for slow walking. Frail elderly adults can often make significant improvements in muscle strength and endurance through exercise. However, such gains have not consistently translated to improved gait performance. These findings are indicative of the complexities of gait performance and indicate the need for a more fundamental understanding of the neuromuscular factors that limit gait speed. This study will employ musculoskeletal models and forward dynamic simulations to describe the causal relationship between muscle actions and movement during gait. These novel analyses will be used to identify limiting factors, describe compensatory mechanisms and predict the affects of specific interventions. Aim 1 will rigorously examine the contributions of muscle coordination, strength, posture and passive joint stiffness to reduced gait speed in healthy old adults. We will test the hypothesis that age-associated reductions in gait speed arise primarily due to increased passive stiffness at the hip and only secondarily due to diminished muscle power at the ankle. Aim 2 will identify the subject-specific factors that limit gait speed in elderly who exhibit intermediate frailty. We hypothesize that identifiable subject-specific limitations in either passive hip flexion stiffness, ankle plantarflexor power capacity or hip abduction weakness will be the primary factors limiting gait speed in elderly who walk slowly. The development of forward dynamic simulations that elucidate how muscles contribute to both normal and impaired movement, as proposed here, is an important step to understanding the causes of slow walking among frail elderly. The results of this study are fundamental to the development of effective interventions that can improve gait function and thereby contribute to the maintenance of mobility in elderly adults