Department of Human Movement Sciences, Faculty of Health, Medicine and Life Sciences, Maastricht University, P.O. Box 616, 6200 MD Maastricht, The Netherlands.
Hum Mov Sci. 2012 Dec;31(6):1560-70. doi: 10.1016/j.humov.2012.05.003. Epub 2012 Jul 31.
The purpose of this study was to examine dynamic stability control in older and younger adults while descending stairs. Thirteen older (aged 64-77 years) and 13 younger (aged 22-29 years) adults descended a staircase at their preferred speed. A motion capture system and three force plates were used to determine locomotion mechanics. Dynamic stability was investigated by using the margin of stability, calculated as the instantaneous difference between anterior boundary of the base of support and extrapolated centre of mass. At the initiation of the single support phase, older adults demonstrated a more negative (p<.05) margin of stability value. The component responsible for the lower margin of stability in the elderly was the higher velocity of the centre of mass (p<.05). Before the initiation of the single support phase, the older adults showed a lower (p<.05) ankle and knee joint angular impulse compared to the younger ones. We found a significant correlation (r=.729, p<.05) between centre of mass velocity and joint angular impulse. These results indicate that older adults are at greater risk of falls while descending stairs potentially due to a reduced ability to generate adequate leg-extensor muscular output to safely control the motion of the body's centre of mass while stepping down.
本研究旨在探讨老年人和年轻人在下楼梯时的动态稳定性控制。13 名老年人（年龄 64-77 岁）和 13 名年轻人（年龄 22-29 岁）以自己喜欢的速度下楼梯。运动捕捉系统和三个测力板用于确定运动力学。通过稳定性裕度来研究动态稳定性，计算为支撑基础的前边界和质心外推之间的瞬时差值。在单支撑阶段开始时，老年人的稳定性裕度值更负（p<.05）。老年人稳定性较低的原因是质心速度较高（p<.05）。在单支撑阶段开始之前，与年轻人相比，老年人的踝关节和膝关节角动量较低（p<.05）。我们发现质心速度与关节角动量之间存在显著相关性（r=.729，p<.05）。这些结果表明，老年人在下楼梯时跌倒的风险更高，可能是因为他们无法产生足够的腿部伸展肌输出，无法安全地控制身体质心在踏步时的运动。
