Department of Health and Kinesiology, Purdue University, West Lafayette, IN, United States; Center on Aging and the Life Course, Purdue University, West Lafayette, IN, United States.
Department of Health and Kinesiology, Purdue University, West Lafayette, IN, United States; Center on Aging and the Life Course, Purdue University, West Lafayette, IN, United States.
J Biomech. 2021 Mar 30;118:110311. doi: 10.1016/j.jbiomech.2021.110311. Epub 2021 Feb 9.
Community ambulation requires gait adaptations to navigate environmental obstacles. It is well known that while crossing obstacles, variables quantifying the gait pattern are controlled relative to the obstacle's position. However, the stability of these gait variables is underexplored. We measured foot positions relative to an obstacle as young and older adults stepped over it. We report secondary analysis of this data in which we quantified the stability of the step length when the two feet are placed on either side of the obstacle. We employed the uncontrolled manifold approach to test the hypotheses that (1) synergistic across-trial co-variation in the distances of the front and the back heel from the obstacle edge will stabilize the step length, and (2) older adults will display weaker synergies (i.e., lower step length stability). We observed that the front and back heel distances relative to the obstacle's edge co-varied synergistically to stabilize the step length for both age groups. Therefore, foot placement during obstacle navigation is controlled not only with reference to a feature of the environment (i.e. the obstacle), but also to stabilize the step length, presumably to control COM motion. The synergy index was 38% lower for older adults than young adults. This decline may be associated with aging-related functional deficits and tripping-related falls.
社区活动需要适应步态以穿越环境障碍物。众所周知，当跨越障碍物时，用于量化步态模式的变量相对于障碍物的位置进行控制。然而，这些步态变量的稳定性还没有得到充分的探索。我们测量了年轻人和老年人在跨过障碍物时脚相对于障碍物的位置。我们报告了对此数据的二次分析，其中我们量化了双脚放在障碍物两侧时步长的稳定性。我们采用非控制流形方法来检验以下假设：(1) 前脚和后脚跟与障碍物边缘的距离在跨试验协同变化，将稳定步长，以及 (2) 老年人将显示出较弱的协同作用（即，步长稳定性较低）。我们观察到，前脚和后脚跟相对于障碍物边缘的距离协同变化以稳定两个年龄组的步长。因此，在障碍物导航过程中，脚的放置不仅是参照环境的一个特征（即障碍物），而且是为了稳定步长，大概是为了控制 COM 运动。与年轻人相比，老年人的协同指数低 38%。这种下降可能与与年龄相关的功能缺陷和与绊倒相关的跌倒有关。
