Impacts of a Workplace-Based Weight-Control Intervention on Objective and Perceived Physical Activity among a Subgroup of Workers.

Physical activity (PA) has many benefits; however, groups facing barriers to health-promoting behaviors are less likely to be physically active. This may be addressed through workplace interventions. The current study employs objective (accelerometry) and perceived (International Physical Activity Questionnaire [IPAQ]) measures of PA among a subset of participants from the "Working for You" study, which tests a multi-level (work group and individual) workplace intervention targeted at workers with low-incomes. Linear mixed and hierarchical logistic regression models are used to determine the intervention's impact on moderate- to vigorous-PA (MVPA) and achieving the PA Guideline for Americans (≥150 minutes MVPA/week), respectively from baseline to 6- and 24-months, relative to a control group. Correlations (Spearman Rho) between perceived and objective PA are assessed. Of the 140 workers (69 control, 71 intervention) in the sub-study, 131 (94%) have valid data at baseline, 88 (63%) at 6-months, and 77 (55%) at 24-months. Changes in MVPA are not significantly different among intervention relative to control participants assessed by accelerometer or IPAQ at 6- or 24-months follow-up. The percent achieving the PA Guideline for Americans does not vary by treatment group by any measure at any time point (e.g., baseline accelerometry: [control: n=37 (57%); intervention: n=35 (53%)]). This study identifies limited agreement (correlation range: 0.04 to 0.42, all p>.05) between perceived and objective measures. Results suggest the intervention did not improve PA among the sub-study participants. Though agreement between objective and perceived MVPA is low, similar conclusions regarding intervention effectiveness are drawn.