Department of Physical Therapy, Human Health Sciences, Graduate School of Medicine, Kyoto University, 53 Kawahara-cho, Shogoin, Sakyo-ku, Kyoto, Japan.
J Gerontol A Biol Sci Med Sci. 2011 Aug;66(8):904-9. doi: 10.1093/gerona/glr081. Epub 2011 Jun 9.
Obstacles are a common cause of falls among older adults. Anticipatory motor planning for obstacle negotiation must be completed during the precrossing phase in order to step over the obstacle safely. This cognitive load may affect anticipatory postural adjustments (APAs) in older adults at high risk of falling. This study explored the effect of obstacle negotiation on APA during gait initiation in older adults at high risk of falling.
Seventy-six elderly volunteers (mean age: 80.5 [7.6 years]) from the community participated in this study. Participants performed gait initiation tasks from a starting position on a force platform under the following two conditions: (1) unobstructed (smooth walkway) and (2) obstructed (walkway with an obstacle placed at 1 m from the initial position). The reaction and APA phases were measured from the data of center of pressure. Each participant was categorized as a high-risk or a low-risk individual according to the presence or absence of a fall experience within the past year.
High-risk participants had significantly longer APA phases than low-risk participants under the obstructed condition even though there was no significant difference between groups under the unobstructed condition. Reaction phase was not significantly different between groups in either the unobstructed or the obstructed condition.
Motor performance deterioration occurred in high-risk participants in the beginning of the precrossing phase of obstacle negotiation. A slow and inefficient APA at the precrossing phase of obstacle negotiation might be one of the causes of accidental falls.
障碍物是老年人跌倒的常见原因。为了安全地跨过障碍物，老年人必须在预过阶段完成对障碍物的预期运动规划。这种认知负荷可能会影响有跌倒高风险的老年人的预期姿势调整（APAs）。本研究探讨了在有跌倒高风险的老年人开始行走时，障碍物协商对 APA 的影响。
本研究共纳入 76 名来自社区的老年志愿者（平均年龄：80.5 [7.6 年]）。参与者在力平台上从起始位置开始进行行走启动任务，在以下两种条件下进行：（1）无障碍（平滑步道）和（2）有障碍（在初始位置 1 米处放置障碍物的步道）。从压力中心数据中测量反应和 APA 阶段。根据过去一年是否有跌倒经历，将每个参与者分为高风险或低风险个体。
在有障碍物的情况下，高风险参与者的 APA 阶段明显长于低风险参与者，尽管在无障碍条件下两组之间没有显著差异。在无障碍或有障碍物的情况下，两组之间的反应阶段没有显著差异。
在障碍物预过阶段，高风险参与者的运动表现恶化。在障碍物预过阶段缓慢且效率低下的 APA 可能是意外跌倒的原因之一。
