Maintenance of physical activity gains among Latina teens: 12-month findings from the Chicas Fuertes randomized controlled trial

BACKGROUND: Only about three percent of Latina teens are sufficiently active. As Latinas have a higher prevalence of lifestyle-related chronic health conditions, such as diabetes, compared to non-Latinas, targeted interventions that increase and maintain moderate-to-vigorous-intensity physical activity (MVPA) are needed. Chicas Fuertes is a 12-month multi-channel mHealth physical activity intervention for Latina teens shown to increase MVPA over the first six months. The purpose of this study was to test the effectiveness of Chicas Fuertes for maintaining Latina teens' initial physical activity gains over the subsequent six months. METHODS: In a randomized controlled trial, Latina teens, aged 13 -18 and underactive, participated in Chicas Fuertes or served as a control. The intervention group initially received a Fitbit, a one-on-one coaching session and two check-in calls, access to a personalized website, tailored text messages, and daily Instagram content while the control group received only a Fitbit. From six to 12-months, the intervention group received a short coaching call and continued access to the tailored digital media content. Weekly minutes of MVPA were assessed at baseline, six, and 12-months with hip-worn Actigraph GT3X+ accelerometers and the 7-Day Physical Activity Recall Interview. Mixed effects regressions were conducted to examine between-group differences in MVPA at twelve months, with models of accelerometer data adjusting for device wear-time. RESULTS: Of the 160 participants (Mage= 15.9 ± 1.6),137 completed the 12-month follow-up. More than half (69%) identified as second-generation and reported a household income of ≤$50,000 (62%). Weekly minutes of MVPA gained at six months were maintained at twelve months in Chicas Fuertes participants compared to control. Intervention participants had increased median changes in accelerometry-measures, 10.00 (IQR=13), compared to decreases observed in the control, -5 (IQR=21). Median changes in self-reported measures 13 (IQR=32) among intervention compared to 5 (IQR=26) among control. CONCLUSIONS: Chicas Fuertes was able to support maintenance of objective and self-reported MVPA gains from six months to twelve months with tapered support. Digital technologies that Latina teens commonly use can be leveraged to increase dissemination and implementation of physical activity interventions at a relatively low cost, ultimately enhancing health equity among Latina teens. TRIAL REGISTRATION: ClinicalTrials.gov NCT04190225. Registered on November 20, 2019.