Abstract

Purpose

Coordinated movements of both lower limbs may be a clinically important indicator of motor control during quiet standing. From a neurological point of view, it is known that extensive coupling of muscles must be coordinated an upright posture. However, movement coordination between the lower limbs is the final motor output, is unknown. In this study, we focussed on the ground reaction force (GRF) vector and clarified the time and frequency characteristics of the force vectors of both lower limbs.

Materials and methods

A total of 16 healthy young adults and 18 healthy older adults participated and placed each bare foot on one of two force plates to measure the GRF vectors (i.e., anteroposterior, mediolateral, and vertical) of each lower limb and determine the centre of mass (COM) acceleration in the anteroposterior direction (COMacc). Characteristics of the coordination of both lower limbs during movements were analysed using coherence analysis and cross-correlation function analysis (CCF).

Results

The coherence levels of the force vectors of both lower limbs were higher in all three directions and significantly increased in the older adults. CCF analysis showed that the force vectors of both lower limbs were negatively correlated at the zero-time lag. Moreover, a weak correlation was observed between COMacc and coherence values.

Conclusions

The assessment of bilateral lower limb connectivity using force vectors can be used as an evaluation method to reflect changes in the ability to control bipedal standing during ageing.

中文翻译：

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站立时双下肢协调与身体摇摆控制与衰老的关联

摘要

目的

双下肢的协调运动可能是安静站立时运动控制的重要临床指标。从神经学的角度来看，众所周知，肌肉的广泛耦合必须协调直立姿势。然而，下肢之间的运动协调是最终的运动输出，是未知的。在本研究中，我们重点研究了地面反作用力（GRF）矢量，阐明了双下肢力矢量的时频特性。

材料和方法

共有 16 名健康的年轻人和 18 名健康的老年人参与并将每只赤脚放在两个测力台之一上，以测量每个下肢的 GRF 向量（即前后、中间和垂直）并确定重心（ COM) 前后方向的加速度 (COMacc)。使用相干分析和互相关函数分析（CCF）分析运动过程中双下肢协调的特征。

结果

两个下肢力向量的相干水平在所有三个方向上都较高，并且在老年人中显着增加。CCF分析表明，在零时滞下，双下肢的力向量呈负相关。此外，在 COMacc 和相干值之间观察到弱相关性。

结论

使用力向量评估双侧下肢连通性可作为一种评估方法，以反映衰老过程中控制双足站立能力的变化。