Abstract TU211: Feasibility and Preliminary Effects of a Web-Based Physical Activity Program for Adults with Obesity: Results from a Pilot Randomized Controlled Trial

Background: Adults with obesity face multifaceted barriers to physical activity (PA), including stigma, low self-efficacy, and limited access to relatable content. Traditional interventions fail to address these obesity-specific barriers. Objective: To evaluate the feasibility and preliminary effects of a web-based PA for the Heart (PATH) intervention among insufficiently active adults with obesity. Methods: This 6-month pilot randomized controlled trial enrolled 89 participants (aged ≥18 years, BMI ≥30 kg/m2, <150 minutes moderate-to-vigorous PA MVPA/week) randomized 1:1 to PATH intervention or control. PATH participants received access to PATH platform with curated workouts, health coaching, and self-monitoring tools. Controls received the "Be Active Your Way" guide. Data were analyzed using t-tests and ANCOVA models adjusting for baseline values. Outcomes included platform acceptability, PA changes and cardiometabolic risk factors. Results: The sample was 91% female, 46% white, with mean BMI of 40.35±7.20 kg/m2 and mean age 48.66±12.17 years. The study demonstrated feasibility (recruitment completed in 6 months, 91% retention). PATH demonstrated high acceptability, with mean System Usability Scale (SUS) score of 81.4±13.5, 85.3% weekly engagement, and 97.2% rating PATH workouts as culturally appropriate. There were significant baseline imbalances in Fitbit MVPA (control 351.5 vs PATH 176.2 min/wk, p=0.021) and weight-loss medication use at end of study (Control: 9.1%, PATH: 2.2%, p=0.159). Within-group analyses showed significant PA decline in the control group (ActiGraph MVPA: -47.0/wk, p=0.090; Fitbit MVPA –104.4, p=0.232, steps -941.6/day, p=0.096) while the PATH group maintained baseline levels (ActiGraph MVPA: -0.5, p=0.985; Fitbit MVPA -12.2, p=0.715, steps -318.4/day, p=0.543). Sensitivity analyses adjusting for baseline Fitbit MVPA confirmed robustness of findings. The PATH group showed significant improvements in exercise goal setting (Cohen's d=0.347, p=0.002) and PA enjoyment (Cohen's d=0.59, p=0.007). Conclusions: The PATH intervention demonstrated strong acceptability and protective effects against natural PA decline in adults with obesity, supporting technology-enhanced approaches for this high-risk population.