Randomized controlled trial of a multiple technology-based physical activity intervention for Latina adolescents: Recruitment strategies and baseline data from the Chicas Fuertes trial

Background: Latina adolescents report low levels of physical activity (PA) and high lifetime risk of lifestyle-related diseases. They also have high rates of using technology, suggesting interventions delivered through mobile devices may be effective for this population. The current paper describes recruitment methods and baseline study characteristics for Chicas Fuertes, a fully powered randomized trial of a mobile technology PA intervention. Methods: Underactive Latina adolescents (aged 13-18) were recruited using social media and presentations at local schools and community organizations in San Diego, California. Participants were randomly assigned 1:1 to either the intervention (Fitbit, tailored texting, social media, and website) or control group. Baseline measures included demographics, psychosocial variables, and PA measured by the 7-Day Physical Activity Recall (PAR), ActiGraph GT3X+ accelerometers, and Fitbits. Baseline data were collected from 2020 to 2023. Results: Social media yielded the most contacts (465), but had the lowest chance of enrollment (14 %, vs. 52 % from school presentations). Participants (N = 160) were mostly second generation (68.8 %), and low income (61.8 %), but technology access was high (>99 %). Median self-reported moderate-to-vigorous PA (MVPA) using the 7-Day PAR was 120 min/week (range 0-720), and median daily steps were 5222 (IQR 359). Median MVPA measured by ActiGraphs, however, was 0 min per week. There was no correlation between the 7-day PAR and ActiGraphs (rho = .13, p = .12). However, ActiGraph MVPA was correlated with total steps recorded by the Fitbit (rho = .38, p < .001). Conclusions: Both remote and in-person approaches were successful in recruiting a sample that was underactive and low income, but had high technology use.