Association between objectively measured habitual physical activity levels and mobility limitation: A cross-sectional study of community-dwelling older Japanese women

Abstract

Cut-off values of habitual physical activity to determine mobility limitation (ML) would be useful for recommending modifications to life activities for community-dwelling older Japanese women. Accordingly, the aim of this study was to determine the levels of habitual physical activity (step counts: SC, moderate-vigorous physical activity: MVPA) capable of predicting ML in older women. This study included 630 community-dwelling older Japanese women (72.3 ± 5.9 years). ML was assessed in two consecutive self-reports, and defined as having some difficulty or being unable to walk one-quarter of a mile or climb 10 steps without resting. A uniaxial accelerometer continuously measured SC and MVPA for over 10 h/day for 7 days. Receiver operating characteristic analysis was conducted to determine the cut-off values of SC and MVPA that could predict ML. Results show that the prevalence of ML in this study was 28.3% (n = 178). The optimal cut-off values of SC and MVPA for predicting ML were 5,773 steps/day (sensitivity: 66.3%, specificity: 70.8%) and 107.4 min/week (sensitivity: 84.8%, specificity: 55.3%). It was concluded that the levels of SC and MVPA capable of predicting ML were 5,773 steps/day or 107.4 min/week for older Japanese women. Although these levels of habitual physical activity would be useful as an indicator in modifying the life activities in older Japanese women, the validity of the cut-off values for predicting ML will need to be confirmed in longitudinal studies.

Keywords

• cut-off values
• mobility limitation
• physical activity
• older women
• receiver operating characteristic analyses