Smartphone-Based Field Assessment of Trunk Stability and Its Relationship With Whole-Body Balance in Older Adults: Cross-Sectional Study

BACKGROUND: Maintaining balance is essential for older adults to preserve independence and reduce fall risk. However, empirical evidence linking trunk stability with balance and gait is scarce, partly due to the lack of accessible field tests. Smartphone-based accelerometry field tests offer a promising approach to assess trunk stability outside the laboratory. OBJECTIVE: To determine (a) the association between trunk stability and whole-body balance and gait, and (b) the extent to which trunk stability and whole-body balance field tests align with laboratory-based assessments in older adults. METHODS: Fifty-seven physically active older adults performed two trunk stability tests (i.e., the lumbopelvic stability [field] and the unstable sitting posturographic [laboratory] tests), two whole-body balance tests (i.e., the tandem stance posturographic [laboratory] and the whole-body static balance [field] tests) and two gait-related tests (i.e., the straight-line gait and the modified Timed Up & Go [field] tests) two times. A Spearman correlation analysis was performed after assessing the reliability of the variables. RESULTS: Significant positive low-to-high correlations were found between the lumbopelvic stability and the whole-body static balance tests (.380≤r≤.700, P