ROLE OF WALKING STABILITY IN FALLS AMONG THE ELDERLY

描述(申请人提供)：人们普遍认为，只要走得慢一些，人就可以更安全、更稳定。与这个一般概念相反，我们最近的计算机模型模拟表明，在滑行开始时，身体重心(COM)的较慢速度实际上可能会降低稳定性，从而导致向后失去平衡。在滑步开始时，更快的移动和/或更前移的COM可以快速地向前推进，追上他/她滑倒的脚，从而避免向后摔倒。 矛盾的是，这些发现表明，与年龄相关的步态缓慢，而不是更安全，实际上可能会使老年人更容易摔倒，这至少在一定程度上解释了老年人摔倒的较高发生率。然而，一个可能的缓解因素是，老年人可以通过缩短步长来潜在地补偿由于缓慢而导致的不稳定，从而使COM相对于支撑基向前移动。老年人对缓慢相关的步态不稳定的补偿程度在很大程度上是未知的。 在某种程度上，成功的康复可能依赖于反应性踏步，尽管我们的初步发现表明，这种踏步在老年人中失败的频率高于年轻人。然而，我们的初步发现也表明，在反复暴露于诱导性滑倒之后，年轻人和老年人通过向前移动COM和增加速度来提高他们在滑倒开始时的稳定性，从而避免摔倒。因此，成功的主动行为(例如，改变组件位置和速度以提高稳定性)可以减少甚至消除对反应性阶跃响应的需求。在以下三个既定目标中，我们正在开创一系列研究来调查这些问题，同时探索有效干预的机制，以减少与滑倒相关的跌倒发生率。 目的1：我们将测试步态稳定性和滑行相关跌倒风险之间的理论关系。目的2：我们将确定与年龄相关的跌倒发生率的增加是否归因于步态稳定性的降低和/或对新的、意外的跌倒的反应的差异。目的3：我们将确定老年人在反复接触滑倒后是否通过改善步态稳定性和/或增强他们的反应来减少跌倒的发生率。

DESCRIPTION (provided by applicant): It is generally believed that, merely by walking slower, one can be safer and more stable. Contrary to this general concept, our recent computer model simulations showed that, at the onset of a slip, a slower velocity of the body center of mass (COM) may actually decrease stability and thereby lead to a backward loss of balance. A faster moving and/or a more forwardly positioned COM at slip onset can quickly carry the person forward to catch up with his/her slipping foot, thus avoiding a backward fall. Paradoxically, these findings suggest that age-related slowness in gait, rather than being safer, may actually predispose older adults to falling, accounting, at least in part, for a higher fall incidence rate among older adults. One possible mitigating factor, however, is that older adults can potentially compensate for the instability due to slowness by shortening their step length, thereby shifting the COM forward with respect to the base of support. The extent to which older individuals compensate for slowness-related gait instability is largely unknown. Successful recovery may, to some extent, rely on reactive stepping, although our preliminary findings indicate that such stepping fails more frequently in older than in young adults. Nevertheless, our preliminary findings also indicate that, after repeated exposure to induced slips, young and older adults avoided falling by improving their stability at slip onset through a forwardly shifted COM and an increased velocity. Thus, successful proactive behavior (e.g., changes in COM position and velocity to improve stability) can reduce or even eliminate the need for a reactive stepping response. In the following 3 stated aims, we are pioneering a line of research to investigate these issues, while exploring the mechanisms for effective intervention to reduce incidence of slip-related falls. Aim 1: We will test the theorized relationship between gait stability and the risk of slip-related falls. Aim 2: We will determine whether an age-related increase in slip-related fall incidence is attributable to a decrease in gait stability and/or to differences in the reactive response to a novel, unexpected slip. Aim 3: We will determine whether older adults decrease their fall incidence after repeated exposure to slips by improving gait stability and/or by enhancing their reactive responses.