To determine the day-to-day variability of older adults’ physical activity, and to evaluate the accuracy of the 10,000-step goal for classifying whether older adults obtain 30 min of MVPA.
Ninety-one adults ages over 60 y wore a Yamax pedometer and Actigraph accelerometer for 7 days. Interday reliability was estimated via two-way ANOVA ICCs, and classification accuracy was evaluated via sensitivity, specificity, and ROC curve analysis.
Interday reliability was high; four of five outcome measures had a reliability of ≥.80 with only 2 days of data. The 10,000-step cut point had high accuracy for identifying days with less than 30 min of MVPA, but poor accuracy for identifying days with more than 30 min of MVPA.
Day-to-day variability in physical activity is lower in older adults than other age groups. The 10,000-step goal is inadequate for determining whether daily physical activity includes 30 min of MVPA in this population.