This randomized controlled trial (RCT) investigated the effectiveness of a 10-week mobile app intervention to promote physical activity in adolescents, considering gender and academic year as moderators. 400 adolescents (210 males, 190 females) were randomized into experimental (n=240) and control (n=160) groups. The experimental group used four apps (Strava, Pacer, MapMyWalk, Pokémon Go) at least three times a week, increasing weekly distance targets. Results showed higher app usage in females and older adolescents. The intervention prevented increases in fat-related variables (BMI, fat mass, etc.) and improved some fitness variables, particularly in females and older adolescents. Gender and academic year should be considered in future mobile app interventions.
