Brisk walking and postural stability: A cross-sectional study in postmenopausal women

This study compared body sway, a measure of postural stability, between regular brisk walkers and control subjects. Furthermore, the relationship between body sway and physical activity duration in postmenopausal women was examined. Subjects were 31 healthy postmenopausal women, aged 61-71 years. They were recruited from a randomized controlled study of the influence of brisk walking on bone: 16 women had been completing 20 min d-1 brisk walking, whilst 15 controls had been completing habitual activities only. Body sway was measured using a swaymeter that measured displacement at the waist whilst subjects stood on a compliant surface, with eyes closed, for 1 min. The activity was measured using activity monitors which were worn at the waist for 3 consecutive days. Body sway (eyes closed, standing on a compliant surface) was lower in walkers than in controls: 2,958 +/- (SE) 270 versus 5,225+/-371 mm2 min-1, respectively (p < 0.05). A negative correlation was found between body sway and minutes of physical activity (r = -0.47, p < 0.01). Analysis of variance revealed that body sway differed significantly (p < 0.05) between groups of differing physical activity participation, being 4,839 +/- 499, 4,167 +/- 516, and 2,877 +/- 362 mm2 min-1, respectively, in women completing <20, 20-40, and >40 min d-1 of physical activity. Body sway was significantly lower in the most active group than in the least active (p < 0.01). These data suggest that postural stability is better in regular walkers than in control subjects. Furthermore, a dose-response relationship was observed between physical activity and postural stability in postmenopausal women. These findings provide a preliminary indication that brisk walking, a low-cost and acceptable form of physical activity for the elderly, could be incorporated into strategies for improving balance in the elderly.