THE INFLUENCE OF HEIGHT ON TEST-RETEST RELIABILITY OF POSTURAL BALANCE MEASURES IN HEALTHY YOUNG ADULTS

Abstract

Height is associated with postural balance performance. However, there has been no study on whether the test-retest reliability of the balance performance variables is related to height. The goal of our study was to analyze the effect of body height on the test-retest reliability of center of pressure (COP) variables during natural and feet-together stances in healthy young subjects. Twenty normal young men were classified into the short height group (height range, 163–174[Formula: see text]cm) and the tall height group (height range, 176–184[Formula: see text]cm) with 10 subjects each to investigate the influence of height on test-retest reliability. All subjects performed the static balance test on a commercial force plate in feet-together and natural stance conditions three times. Four variables were calculated from the COP data. COP distance, COP area, COP velocity, and COP mean frequency were selected as the postural balance variables. Intraclass correlation coefficient (ICC) was evaluated for an analysis of the test-retest reliability of each COP variable. In both stance conditions, the COP distance and the COP area in the short height group (ICC = 0.717–0.902) showed better test-retest reliability compared to those in the tall height group (ICC = 0.146–0.688). COP velocity had the highest ICC value in both stance conditions (ICC = 0.744–0.970). Additionally, the short height group showed slightly better reliability in the feet-together stance condition, whereas the tall height group showed slightly higher ICC value in the natural stance condition. These results suggest that height should be considered for a more reliable assessment of repetitive static balance performance. Our findings might be useful for the development of an optimal static balance test protocol regardless of the effect of height.