Post Intervention Differences in Steps Accumulated at Moderate Intensity Cadences

Background/Purpose: It has been shown that pedometer-based physical activity interventions are an effective means to promote increases in daily ambulation (steps/day). It is not known however at what cadence (steps/min) participants accumulate more steps in as a result of such interventions. Therefore, the purpose of this study was to determine if participants in a dietary education plus physical activity intervention group (DE+PA) had greater increases in the number of steps accumulated at different cadence bands than a dietary education only group (DE).

Method: Overall, 121 White and African-American adults (ages 35 - 64 y; BMI 25-34.9 kg/m²) were randomized to a DE+PA (n=60) or DE (n=61) group. The 12 week intervention for the DE+PA group was designed to increase daily steps, and more specifically steps taken at moderate-to-vigorous intensity (≥ 100 steps/min). The primary goal of the intervention was to increase adherence to current public health recommendations calling for 30 min/day of moderate-to-vigorous physical activity. All study procedures were approved by the Pennington Biomedical Research Center’s Institutional Review Board. Written informed consent was obtained from all participants. The Actigraph GT3X+ accelerometer was used to measure steps in 60 sec epochs. The number of steps accumulated in different cadence bands (1-19, 20-39, 40-59, 60-79, 80-99, 100-119, 120+ steps/min) was calculated for each day and averaged across valid days. Only participants with 4+ valid days (> 10 hours of wear time/day) at pre- and post-intervention were included in this analysis. Pre- to post-intervention changes in average steps/day and steps accumulated within each cadence band were compared between groups after adjustment for baseline values. 

Analysis/Results: Eighty nine participants had valid data at baseline and follow-up (44 in the DE+PA group). Differential changes in total steps/day for the DE+PA and DE groups (+1063±2429 and +350±1997 steps/day, respectively) were not significant. Participants in the DE+PA group accumulated significantly more steps than those in the DE group within the 100-119 (463±1092 vs 57±554 steps/day; p = 0.01) and 120+ (390±999 vs 34±325 steps/day; p = 0.03) cadence bands. 

Conclusions: Participants in the DE+PA group spent more time engaged in moderate intensity ambulatory activities known to improve health. Although differential changes in total steps/day were not significant between groups, significantly more steps were accumulated at higher cadences with a physical activity intervention.

Funding: ARS/USDA Cooperative Agreement #58-6251-8-038.

ClinicalTrials.gov Identifier: NCT01584596