PDF(Pubmed)
Abstract：
OBJECTIVE: A U-shaped relationship between energy cost of walking (Cw) and walking speed indicates that there is a specific speed minimizing the Cw, called economical speed (ES). It is mostly slower in older adults than young adults; however, effects of leg length on the ES have been ignored. We investigated effects of aging and exercise habituation on the normalized ES by leg length (ESnormalized). We quantified time delay of stride length and step frequency in sedentary young (SY), active young (AY), and active elderly (AE) adults in response to sinusoidal gait speed change at 30-s and 180-s periods with an amplitude of ± 0.56 m･s- 1.
RESULTS: The ES was significantly slower in the following sequence: AE, SY, and AY, whereas ESnormalized was slower in the AE than in other young groups, with no difference between AY and SY. AE and SY showed greater step variabilities at the 180-s period, whereas AY showed relatively smaller step variabilities at both periods. Collectively, the ESnormalized slowed due to aging, not due to exercise habituation. When optimizing the appropriate SL-SF combination for sinusoidal speed changes, young and elderly adults may adopt different strategies. Exercise habituation may reduce step variabilities in young adults.
RESULTS: The ES was significantly slower in the following sequence: AE, SY, and AY, whereas ESnormalized was slower in the AE than in other young groups, with no difference between AY and SY. AE and SY showed greater step variabilities at the 180-s period, whereas AY showed relatively smaller step variabilities at both periods. Collectively, the ESnormalized slowed due to aging, not due to exercise habituation. When optimizing the appropriate SL-SF combination for sinusoidal speed changes, young and elderly adults may adopt different strategies. Exercise habituation may reduce step variabilities in young adults.
摘要：
目的：步行的能量成本（Cw）与步行速度之间的U形关系表明，存在使Cw最小化的特定速度，称为经济速度（ES）。老年人比年轻人更慢；然而，腿长度对ES的影响被忽略。我们调查了衰老和运动习惯对腿长归一化ES的影响（ES归一化）。我们量化了久坐的年轻人(SY)的步幅和步频的时间延迟，活跃的年轻人（AY），和活跃的老年人（AE）成年人在30-s和180-s周期内响应正弦步态速度变化，振幅为±0.56m•s-1。
结果：ES在以下顺序中明显变慢：AE，SY,AY,而ESnormalized在AE中比其他年轻组慢，AY和SY没有区别。AE和SY在180-s期间显示出更大的阶跃变化，而AY在两个时期都显示出相对较小的步长变化。总的来说，由于老化，ESnormalized减慢，不是由于锻炼习惯。当针对正弦速度变化优化适当的SL-SF组合时，年轻人和老年人可能会采取不同的策略。运动习惯可能会减少年轻人的步调变化。
结果：ES在以下顺序中明显变慢：AE，SY,AY,而ESnormalized在AE中比其他年轻组慢，AY和SY没有区别。AE和SY在180-s期间显示出更大的阶跃变化，而AY在两个时期都显示出相对较小的步长变化。总的来说，由于老化，ESnormalized减慢，不是由于锻炼习惯。当针对正弦速度变化优化适当的SL-SF组合时，年轻人和老年人可能会采取不同的策略。运动习惯可能会减少年轻人的步调变化。
