Background

Despite strong evidence that walking speed and forward propulsion decline with increasing age, their relationship is still poorly understood. While changes in the ankle and hip mechanics have been described, few studies have reported the effect of ageing on the whole leg’s contribution to propulsion.

Research question

The aim of this study was to investigate age-related changes in the work performed by the leg on the center of mass (COM) push-off power during walking in adults aged 20–86 years. Specifically, we evaluated how deterioration in COM push-off power relates to changes in ankle and hip kinetics as well as age and walking speed.

Methods

Motion, ground reaction forces and gastrocnemius muscle activity were recorded in 138 adults during overground walking at self-selected speed. Age-related differences in variables between decades were analyzed with an ANOVA, while the relation between COM push-off power and joint kinetic variables, as well as walking speed and biological age, was evaluated using correlations and multiple regression analysis.

Results

From the age of 70 years and onwards, COM push-off power was significantly decreased. The decline in COM push-off power was mostly explained by a decline in average ankle push-off power (72 %), and to a lesser extent by peak hip extension moment (3 %). There was no re-distribution of ankle-to-hip push-off power. The decline in COM push-off power seemed more related to walking speed (explaining 54 % of the variance) than biological age (only 4 %).

Significance

Findings indicate that age-related decline in COM push-off power in able-bodied adults starts from the age of 70 years, which is before changes have been found in kinematics, but still later than generally presumed. This decrease in push-off power was more related to walking speed than biological age, which emphasizes the need to better understand the reason for speed decline in older adults.

中文翻译：

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几十年来老年人的步态推进力下降

背景

尽管强有力的证据表明步行速度和向前推进力随着年龄的增长而下降，但它们之间的关系仍然知之甚少。虽然已经描述了踝关节和髋关节力学的变化，但很少有研究报告老化对整个腿对推进力的影响。

研究问题

本研究的目的是调查 20-86 岁成年人在步行过程中腿对重心 (COM) 推力所做功的年龄相关变化。具体来说，我们评估了 COM 推出力的恶化与踝关节和髋关节动力学以及年龄和步行速度的变化之间的关系。

方法

运动、地面反作用力和腓肠肌活动在 138 名成年人以自选速度进行地上行走时被记录下来。使用方差分析分析了几十年之间与年龄相关的变量差异，同时使用相关性和多元回归分析评估 COM 推力和关节动力学变量之间的关系，以及步行速度和生物年龄。

结果

从 70 岁开始，COM 推出力显着下降。COM 推出功率下降的主要原因是平均踝关节推出功率下降 (72%)，在较小程度上由峰值髋部伸展力矩 (3%) 解释。没有重新分配脚踝到臀部的推力。COM 推力的下降似乎与步行速度（解释了 54% 的方差）有关，而不是与生物学年龄（仅 4%）有关。

意义

研究结果表明，身体健全的成年人的 COM 推力与年龄相关的下降从 70 岁开始，这是在运动学中发现变化之前，但仍比通常假设的要晚。这种推动力的下降与步行速度的关系比生理年龄更大，这强调需要更好地了解老年人速度下降的原因。