Biomechanics of slips in older adults

描述（由申请人提供）：由外部扰动引起的跌倒，如滑倒、绊倒和绊倒，对老年工人的健康构成严重危害。实验研究提供了对扰动的姿势反应的一般描述。然而，由于姿势控制系统的复杂性和关键步态变量之间的显著相关性，仅通过实验来解开失败的恢复尝试的原因是具有挑战性的。滑倒过程中姿势反应的正向模拟将与实验数据结合使用，以确定受试者特定的生物力学限制，解释老年人滑倒的原因。更具体地说，我们将确定滑移的程度取决于随年龄变化的步态变量，包括步长和质心加速度（目标1），强度和扭矩产生率能力（目标2）。最后，在目标3中，我们将使用具有解释变量的多元回归模型来预测滑动的大小，这些解释变量(1)在模拟中已被确定为减少滑动和跌倒风险的关键变量，并且(2)可以在无滑的环境中测量。为了收集实现本项目目标所需的实验数据，将招募107名年龄在55岁至70岁之间的老年人参与。实验对象将在又干又滑的地板上行走。将收集两个年龄组的强度数据。模拟将基于主体特定的身体模型，由生理动机控制器产生的扭矩驱动。与公共卫生相关：总之，通过滑倒的实验和模拟，该项目将系统地识别与年龄相关的易导致老年工人滑倒的生物力学限制。这些生物力学限制可能是神经肌肉控制和感觉整合的潜在缺陷的结果，但它们是外部扰动无法恢复的最终原因。这一基本知识是计划、制定和实施有效的针对缺陷的干预措施所必需的，这些干预措施的重点是将工作场所摔倒的风险降至最低。

DESCRIPTION (provided by applicant): Falls initiated by external perturbations such as slips, trips and stumbles are a serious health hazard to older workers. Experimental studies have provided a general description of postural responses to perturbations. However, causes of failed recovery attempts are challenging to disentangle through experiments alone due to the complexity of the postural control system and the significant degree of correlation among key gait variables. Forward simulations of postural responses during slipping will be used in conjunction with experimental data to identify subject-specific biomechanical limitations that explain why older adults slip and fall. More specifically, we will determine the extent to which the magnitude of the slip depends on gait variables that change with aging including step length and center of mass acceleration (Aim 1), strength and torque generation rate abilities (Aim 2). Finally in Aim 3, we will predict the magnitude of a slip using a multi- regression model with explanatory variables that (1) have been identified in the simulations as key variables to reduce the risk of slips and falls, and (2) can be measured in non-slippery environments. To collect the experimental data required to achieve the aims of this project, one hundred seven (N = 107) older adults between the ages of 55 and 70 years old will be recruited for participation. Subjects will walk on dry and slippery floors. Strength data will be collected in both age groups. Simulations will be based on subject- specific models of the body driven with torques generated by a physiologically motivated controller. Relevance to public health: In summary, through experiments and simulations of slipping, this project will systematically identify aging-related biomechanical limitations that predispose older workers to slip and fall. These biomechanical limitations may be the result of underlying deficits in neuromuscular control and sensory integration but they are the ultimate cause of failed recoveries from external perturbations. This fundamental knowledge is required to plan, to develop and to implement effective deficits-targeted interventions focused on minimizing the risk of falling in the workplace.