ROLE OF WALKING STABILITY IN FALLS AMONG THE ELDERLY

描述（申请人提供）：一般认为，只要走得慢一点，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，在滑动开始时，身体质心（COM）的速度较慢，实际上可能会降低稳定性，从而导致向后失去平衡。在滑动开始时更快移动和/或更向前定位的COM可以快速地将人向前携带以赶上他/她的滑动脚，从而避免向后跌倒。 奇怪的是，这些研究结果表明，与年龄相关的步态缓慢，而不是更安全，实际上可能使老年人更容易跌倒，至少部分原因是老年人跌倒发生率较高。然而，一个可能的缓解因素是，老年人可以通过缩短步长来补偿由于缓慢而导致的不稳定性，从而使COM相对于支撑基础向前移动。老年人在多大程度上补偿了与缓慢相关的步态不稳定，这在很大程度上是未知的。 成功的恢复可能在某种程度上依赖于反应性踏步，尽管我们的初步研究结果表明，这种踏步在老年人中比在年轻人中更容易失败。然而，我们的初步研究结果还表明，在反复暴露于诱导滑，年轻人和老年人避免下降，通过提高他们的稳定性，在滑开始通过向前移动COM和速度增加。因此，成功的主动行为（例如，COM位置和速度的变化以提高稳定性）可以减少或甚至消除对反应性步进响应的需要。在以下3个目标中，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，以减少滑倒相关福尔斯的发生率。 目的1：我们将测试步态稳定性和滑倒相关福尔斯风险之间的理论关系。目标二：我们将确定滑倒相关跌倒发生率的年龄相关性增加是否归因于步态稳定性降低和/或对新的意外滑倒的反应性差异。目标3：我们将确定老年人是否通过改善步态稳定性和/或增强他们的反应性反应来减少反复暴露于滑倒后的跌倒发生率。

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.