Bugnariu Nicoleta, Sveistrup Heidi
Cellular and Molecular Medicine, Faculty of Medicine, University of Ottawa, 451 Smyth Road, Ottawa, Ont., Canada K1H 8M5.
Arch Gerontol Geriatr. 2006 Jan-Feb;42(1):73-89. doi: 10.1016/j.archger.2005.05.003. Epub 2005 Aug 9.
This is a cross sectional study of eight healthy young (age 22+/-2 years) and eight healthy older (age 70+/-5 years) adults who participated in an experiment in which they had to keep their balance while standing on a platform moving in the anterior/posterior direction. The 20 cm peak-to-peak platform movements were sinusoidal at increasing frequencies up to 0.61 Hz. The frequency increases were either sudden and unpredictable (externally-triggered perturbations) or controlled by the subjects themselves (self-triggered perturbations). To maintain balance, all subjects used anticipatory adjustments such as early postural muscle activation, leading to fewer steps being taken, tighter coupling of the center of pressure (COP) and the platform movements, and small COP excursions. These adjustments were found to be lacking for externally-triggered perturbations in older subjects; in these subjects the COP range was larger and more often in less safe regions at the boundaries of the base of support.
这是一项横断面研究，研究对象为8名健康的年轻人（年龄22±2岁）和8名健康的老年人（年龄70±5岁），他们参与了一项实验，在实验中，他们必须站在一个前后移动的平台上保持平衡。平台峰峰值为20厘米的运动呈正弦曲线，频率逐渐增加，最高可达0.61赫兹。频率增加要么是突然且不可预测的（外部触发扰动），要么是由受试者自己控制的（自我触发扰动）。为了保持平衡，所有受试者都采用了预期调整，如早期姿势肌肉激活，从而减少了步数，使压力中心（COP）与平台运动的耦合更紧密，且COP偏移较小。研究发现，老年受试者在面对外部触发扰动时缺乏这些调整；在这些受试者中，COP范围更大，且更频繁地处于支撑面边界处较不安全的区域。
