Daily Associations Between Social Support, the Built Environment, and Physical Activity Among Adolescent Girls.

Many adolescent girls fail to meet physical activity (PA) guidelines, with research often overlooking daily influences of social support and built environments on PA. To address this, we employed ecological momentary assessment methods within a social ecological model framework. Girls (n = 66; 12-18 years) reported their social support for PA, built environment perceptions, and time spent in PA over 28 days. Multilevel models indicated that, at the between-person level, girls with higher overall social support tended to engage in more PA (B = 1.50, p < .01). At the within-person level, girls who received more social support than usual (B = 1.37, p < .01), and perceived their environment as more PA conducive than usual (B = 0.75, p < .01), engaged in more PA on those days. No association was found between built environment perceptions and PA, nor did social support interact with these perceptions (p = .33). Our findings emphasize the importance of promoting social support in adolescent girls.