Long-term tracking of physical activity behaviors in women: the WIN Study.

PURPOSE: Interest lies in the prevalence of community-living women meeting the 2008 Department of Health and Human Services physical activity guidelines across time. The purpose was to report prevalence and stability of long-term (up to 125 wk) tracking of physical activity behaviors and to compare self-reported physical activity behaviors using different measures.
METHODS: The WIN study tracks nearly real-time physical activity behaviors in community-living women. At baseline, 918 women began weekly Internet reporting of physical activity behaviors, accessing a secure Internet site and answering eight questions about physical activity behaviors for the previous week. Measures included days and minutes of moderate, vigorous, walking, and strengthening activities, and pedometer steps were recorded weekly.
RESULTS: Prevalence of meeting physical activity guidelines depended on the criterion used. Weekly averages across the surveillance period indicated 25% reported ≥150 min of moderate physical activity, 47% reported ≥75 min of vigorous physical activity, 57% reported ≥150 min of moderate-to-vigorous physical activity, 63% conducted ≥500 MET·min of physical activity, 15% reported ≥2 d of strengthening activities per week, and 39% reported ≥7500 steps per week. Alpha coefficients (≥0.97) indicated stable physical activity behaviors across all measures.
CONCLUSIONS: Across reporting methods, it is estimated that approximately 50% or more of these community-living women engage in sufficient physical activity for health benefits weekly across long-term follow-up. Self-report physical activity behaviors are stable across long periods in these community-living women not participating in a specific physical activity intervention.