How many balance task trials are needed to accurately assess postural control measures in older women?

Abstract

Taking the average of different trials is recommended for better balance assessment, but few studies have really proven this point under different balance conditions.

Objective: To assess the effects of averaging trials of five different balance tasks on postural control measures in older women.

Methods: A total of 90 older women (means: Age: 68 years; Weight: 67 kg; Height: 1.56 m; Body mass index, 27 kg/m²) participated in this study. The participants completed five balance tasks with three performance trials for each task on a force platform in random order. The participants completed a total of three 30-s trials of tasks with 30 s of rest between trials. Repeated measure ANOVA and coefficient of variation were computed to compare differences for one trial vs. averaging across two or three trials on center of pressure (COP) sway values.

Results: There were no significant differences (P > 0.05) in COP sway values when comparing one vs. the average of two or three trials for all balance tasks. However, the coefficient of variation was higher for three trials (10-40%) than two (6-37%) or one trial (3-23%) for COP parameters.

Conclusions: Based on reduction of variability, the present study recommends the averaging of a minimum of two trials for balance assessment in older women. The results of the current study have implications for balance assessment in older people in fall prevention programs.

Keywords: Aging; Outcome measures; Postural balance; Task performance and analysis.