Madigan Michael L, Lloyd Emily M
Department of Engineering Science and Mechanics (0219), Blacksburg, VA, 24061, USA.
J Gerontol A Biol Sci Med Sci. 2005 Jul;60(7):910-4. doi: 10.1093/gerona/60.7.910.
Previous studies have reported that older adults have a reduced ability to recover balance with a single step after a forward-induced fall. To better understand the reasons for this reduced ability, this study investigated any age-related differences in peak joint torques during the support phase of a single-step balance recovery from a forward fall.
Ten young (19-23 years old) and 10 older (65-83 years old) men were released from forward-leaning positions and attempted to recover their balance with a single step. Lean was increased until they failed to recover their balance with a single step. Peak extensor torques were calculated for the support phase of balance recovery and were compared across age groups.
A consistent pattern of joint torques emerged during the support phase of balance recovery, suggesting a similar strategy across young and older participants. Despite this similarity, older participants exhibited smaller peak knee extensor torques during the support phase of single-step balance recoveries, and trends toward larger peak extensor torques at the hip and ankle.
The age-related differences found are believed to be the combined result of an age-related reduction in muscle strength and an age-related neuromuscular adaptation to mitigate the effects of muscle strength loss on physical performance capabilities.
先前的研究报告称，老年人在向前跌倒后单步恢复平衡的能力有所下降。为了更好地理解这种能力下降的原因，本研究调查了从向前跌倒单步恢复平衡的支撑阶段，峰值关节扭矩方面与年龄相关的差异。
让10名年轻男性（19 - 23岁）和10名老年男性（65 - 83岁）从前倾姿势开始，尝试单步恢复平衡。逐渐增加倾斜程度，直到他们无法单步恢复平衡。计算平衡恢复支撑阶段的峰值伸肌扭矩，并在不同年龄组之间进行比较。
在平衡恢复支撑阶段出现了一致的关节扭矩模式，表明年轻和老年参与者采用了相似的策略。尽管存在这种相似性，但老年参与者在单步平衡恢复支撑阶段的峰值膝伸肌扭矩较小，而髋部和踝部的峰值伸肌扭矩有增大趋势。
所发现的与年龄相关的差异被认为是肌肉力量随年龄下降以及神经肌肉随年龄适应以减轻肌肉力量丧失对身体运动能力影响的综合结果。
