Biomechanical Causes of Slow Gait in the Elderly

描述(申请人提供)：这项研究的总体目标是建立对影响老年人行走能力的生物力学因素的科学理解。步行速度是临床上常用的步态表现指标。步行速度慢与跌倒有关，可能导致身体残疾，是描述虚弱综合征的主要标准之一。导致慢步行走的两个因素可能是肌肉力量减少和灵活性降低。干预研究表明，老年人经常可以通过锻炼在力量和灵活性方面取得显着增长。然而，这样的进步往往并没有转化为更快的步行速度。这些不一致的结果可能部分源于对限制老年人步态表现的特定因素的有限理解。 这项研究将使用特定受试者步行模式的正向动态模拟来描述肌肉兴奋和运动之间的因果关系。对老年人步态模拟的分析将被用来严格研究可能限制步态速度的生物力学因素。目标1将研究被动髋屈肌僵硬对步态中多关节运动的贡献。有待检验的假设是，与年轻人相比，随着步态速度的增加，老年人将表现出更多地依赖髋屈肌的紧密性来帮助摆动腿的运动。目标2将确定步态速度是否受到踝屈肌力量能力的限制。这个假设是，健康的老年成年人在走路时不会表现出脚踝力量的局限性。然而，随着步态速度的增加，人们假设老年人将表现出对髋部肌肉的更多依赖，以弥补踝趾屈肌产生向前加速的功能限制。 这些目标的完成是确定老年人步态障碍的限制因素和开发有针对性的干预措施以改善步态表现的重要一步。

DESCRIPTION (provided by applicant): The overall objective of this research is to establish a scientific understanding of the biomechanical factors that govern walking performance in the elderly. Walking speed is a common clinical measure of gait performance. Slow walking speed has been associated with falls, can contribute to physical disability and is one of the primary criteria used to describe the syndrome of frailty. Two factors that may contribute to slow walking are reduced muscle strength and decreased flexibility. Intervention studies have shown that elderly adults can often achieve remarkable gains in strength and flexibility through exercise. However, such gains have often not translated into faster walking speeds. These inconsistent outcomes may stem, in part, from a limited understanding of the specific factors that constrain elderly gait performance. This study will use forward dynamic simulations of subject-specific walking patterns to describe the causal relationship between muscle excitations and movement. Analysis of simulations of elderly adult gait will be used to rigorously investigate biomechanical factors that may limit gait speed. Aim 1 will examine the contributions of passive hip flexor stiffness to the multi-joint movements seen in gait. The hypothesis to be tested is that compared to young adults, elderly adults will exhibit a greater reliance on hip flexor tightness to assist swing leg movement as gait speed is increased. Aim 2 will determine whether gait speed is limited by ankle plantarflexor power capacity. The hypothesis is that healthy elderly adults will not demonstrate limitations in ankle power during walking. However as gait speed is increased, it is hypothesized that elderly adults will exhibit an increased dependence on hip muscles to compensate for functional limitations of the ankle plantarflexors to generate forward acceleration. Completion of these aims is an important step toward characterizing the limiting factors to gait among impaired elderly and developing targeted interventions for improving gait performance.