Postural Instability after Stepping on a Stair in Older Adults: A Pilot Study

Hyokeun Lee,Kyungseok Byun

doi:10.3390/app112411885

Abstract

This study aimed to examine how older adults (OA) control their postural stability after stepping on a stair in comparison to young adults (YA). Ten OA and 10 YA participated in this study. Participants ascended a single stair (15 cm high by 30 cm wide) which was secured atop one of the force plates. Ground reaction forces (GRFs) and center of pressure (COP) motion data were obtained from the force plate under the stair. After standing on the stair with both feet, GRFs and COP data for a 3 s duration were analyzed to assess postural variables, including time to stabilization (TTS), COP velocity (COPVEL), and COP sway area (COPSWAY). A significant difference in TTS in the anterior–posterior direction between OA and YA (p = 0.032) was observed, indicating that OA had difficulty stabilizing their body posture after the stair ascent compared to YA. For COP postural variables, no significant differences in COPVEL (p = 0.455) and COPSWAY (p = 0.176) were observed between OA and YA. Study findings indicate that older adults have less capacity to regain postural stability compared to young adults following a challenging dynamic movement.

Highlights

Postural instability in older adults (OA) leads to impaired balance control when performing activities of daily living, potentially causing an increased risk and incidence of falls and a reduction of independence and quality of life [1]
They reported that stroke patients who had intensive weighted training showed decreased time to stabilization (TTS) scores, indicating their improved capacity to stabilize their postural sway in the face of unpredicted perturbations
Given that a longer time for stabilization is highly correlated with a greater risk of falls [21], our TTS finding supports the observation that OA are at a greater risk of falls compared to young adults (YA)

Summary

Introduction

Postural instability in older adults (OA) leads to impaired balance control when performing activities of daily living, potentially causing an increased risk and incidence of falls and a reduction of independence and quality of life [1]. Given that the biomechanical mechanisms of postural instability in OA have been well documented [2], the balance deficits of OA have been shown to manifest during static movements [3], and during dynamic transitive movement in daily activities [4]. Stabilizing one’s body posture following stair ascent is needed to offset the propulsive momentum generated by the whole body. Individuals with strength deficits may be more impaired at controlling stability after a stair ascent task, exhibiting alterations in their strength compensation strategy. It has been reported that individuals with muscular and neurologic deficits (e.g., osteoarthritis and stroke) are at a greater risk of having a stepping-related fall due to biomechanical and environmental constraints [6,7]

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