Pattern changes in step count accumulation and peak cadence due to a physical activity intervention

Objectives: The purpose was to determine if a 12-week weight loss intervention with a physical activity (PA) component would lead to changes in steps/day, step count accumulation patterns, and peak cadence. Design: Randomized clinical trial. Methods: Overall, 121 overweight/obese White and African-American adults (ages 35-64 yrs) were randomized to a diet education plus PA education and behavior change intervention group (DE + PA) or diet education and behavior change group (DE). The DE + PA intervention was designed to increase steps/day, and steps at moderate-to-vigorous intensity. The Actigraph GT3X+ accelerometer was used to measure steps accumulated in different cadence bands (1-19, 20-39, 40-59, 60-79, 80-99, 100-119, 120+ steps/min), and peak 1-min, 30-min and 60-min cadence. Pre- to post-intervention changes in steps/day, step count within each cadence band, and peak cadences were compared within groups using paired sample t-test and between groups after adjustment for baseline values of the same variable using ANCOVA. Results: Ninety participants had valid data (44 in the DE + PA group). Change in steps/day was not significantly different between the groups. However, participants in the DE + PA group accumulated significantly more steps at post-intervention in the 80-99, 100-119, and 120+ cadence bands, all p < 0.02. The DE + PA group increased step counts accumulated within the 100-119 (463 ± 1092 vs 56 ± 546 step counts; p = 0.01) and 120+ (390 ± 999 vs 34 ± 321 step counts; p = 0.03) cadence bands, as well as peak 60-min cadence when compared to the DE group. Conclusions: Non-significant changes in steps/day following a PA intervention may mask changes in steps accumulated at moderate-to-vigorous intensity cadences.