Department of Physical Education and Kinesiology, Brock University, St. Catharines, Ont., Canada L2S 3A1.
Clin Neurophysiol. 2010 Jan;121(1):109-17. doi: 10.1016/j.clinph.2009.09.025. Epub 2009 Nov 10.
The objectives were to examine (a) whether surface translations with a long, compared to a short, acceleration-deceleration interval could reveal more age-related differences in postural control and (b) whether age-related differences were associated with reactive or anticipatory postural mechanisms.
Ten older (66-81years) and ten young adults (22-39years) stood on a moveable platform that was unexpectedly translated in the backward direction. Subjects' electromyographic (EMG) and kinematic responses were recorded in response to translations with either a SHORT (100ms) or LONG (2s) acceleration-deceleration interval presented in either a predictable or random order.
Age-related differences in kinematic postural responses were greater during LONG compared to SHORT translations. However, both LONG and SHORT translations elicited a similar change in EMG latencies and amplitudes between the older and young adults. No age effects on the presentation order (predictable or random) of the translations were observed.
LONG compared to SHORT surface translations magnify the age-related kinematic but not the EMG changes in reactive postural control. The anticipatory component of postural control was not affected by age.
Translations with longer acceleration-deceleration intervals reveal more age-related differences in postural control, which are otherwise masked by the deceleration effects inherent to shorter translations.
本研究旨在探讨：（a）相较于短加速-减速间隔，长加速-减速间隔的表面平移是否能揭示出更多与年龄相关的姿势控制差异；（b）这些与年龄相关的差异是否与反应性或预期性姿势机制有关。
10 名老年人（66-81 岁）和 10 名年轻人（22-39 岁）站在一个可移动的平台上，该平台向后意外平移。当以可预测或随机顺序呈现加速-减速间隔分别为 SHORT（100ms）和 LONG（2s）的平移时，记录受试者的肌电图（EMG）和运动学反应。
与 SHORT 平移相比，LONG 平移时与年龄相关的运动学姿势反应差异更大。然而，LONG 和 SHORT 平移都在老年人和年轻人之间引起了相似的 EMG 潜伏期和幅度变化。平移呈现顺序（可预测或随机）对年龄没有影响。
与 SHORT 表面平移相比，LONG 表面平移放大了反应性姿势控制中与年龄相关的运动学变化，但对姿势控制的预期成分没有影响。
加速-减速间隔较长的平移揭示了更多与年龄相关的姿势控制差异，否则这些差异会被较短平移固有的减速效应所掩盖。
