Biomechanical Causes of Slow Gait in the Elderly

描述（由申请人提供）：本研究的总体目标是建立对控制老年人步行能力的生物力学因素的科学理解。步行速度是步态表现的常见临床测量。缓慢的步行速度与福尔斯有关，可能导致身体残疾，并且是用于描述虚弱综合征的主要标准之一。两个可能导致慢走的因素是肌肉力量下降和灵活性下降。干预研究表明，老年人通常可以通过锻炼在力量和灵活性方面获得显着的收益。然而，这些收益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源于，部分原因是对限制老年人步态表现的特定因素的理解有限。 本研究将使用特定受试者行走模式的前向动态模拟来描述肌肉兴奋和运动之间的因果关系。对老年人步态的模拟分析将用于严格调查可能限制步态速度的生物力学因素。目的1将检查被动髋屈肌刚度的多关节运动步态中看到的贡献。待检验的假设是，与年轻人相比，随着步态速度的增加，老年人将表现出更大的依赖于髋屈肌收紧来辅助摆动腿运动。目标2将确定步态速度是否受到踝跖屈肌功率容量的限制。假设是健康的老年人在行走过程中不会表现出踝关节力量的限制。然而，随着步态速度的增加，假设老年人将表现出对臀部肌肉的依赖性增加，以补偿踝跖屈肌产生向前加速度的功能限制。 这些目标的完成是一个重要的一步，为特征的限制因素，以步态受损的老年人和发展有针对性的干预措施，以改善步态表现。

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.