Visual dependence, postural stability during repeated unilateral standing tasks, and quality of life in adults with chronic low back pain.

Abstract

Postural deficits are a common impairment in adults with chronic low back pain (LBP). However, the relationship between dynamic sway boundaries, visual reliance, and health-related quality of life (QOL) with LBP remains poorly understood. This study investigated differences in sway excursion, circular stability thresholds, and QOL between adults with and without LBP during repeated unilateral stance tasks under eyes-open and eyes-closed conditions. Eighty adults (45 with LBP, 35 controls) completed three unilateral stance trials on their dominant leg using a force platform. Participants performed three unilateral standing trials under the eyes-open condition and three trials under the eyes-closed condition on each limb. Sway excursion was quantified within 25%, 50%, and 75% circular thresholds inside a fixed 5 cm radius. Eight short form-36 QOL domains, including bodily pain, were used as covariates. Significant main effects were observed for vision (F = 108.17, p < 0.001), trial repetition (F = 15.56, p < 0.001), and boundary threshold (F = 114.20, p < 0.001), along with a significant group interaction for vision × trial × boundary level (F = 4.01, p = 0.04). Post hoc analysis indicated reduced sway excursion in the LBP group, particularly at the 25% and 50% thresholds during trials 2 and 3. QOL-related analyses showed that boundary level was significantly associated with role limitations due to lower physical functioning scores (β = -0.34, p = 0.01). Postural control during unilateral stance is modulated by visual input, task repetition, and spatial constraint. The LBP group demonstrated constrained sway excursion and reduced adaptability, which are reflected in diminished improvements in time-in-boundary across trials, particularly under eyes-closed conditions at wider sway thresholds. These limitations were relevant with lower physical functioning.