LAUSR

BACKGROUND We investigated the percentage of insufficiently active adolescents who became young adults meeting moderate to vigorous physical activity (MVPA) guidelines. We also explored adolescent psychosocial and environmental factors that predicted MVPA guideline adherence in young adulthood. METHODS Participants included N = 1001 adolescents (mean age = 14.1 y) reporting < 7 hours per week of MVPA and followed (8 y later) into young adulthood through Project EAT. We examined mean weekly hours of MVPA, MVPA change between adolescence and young adulthood, and the proportion of participants meeting MVPA guidelines in young adulthood. With sex-stratified logistic regression, we tested 11 adolescent psychosocial and environmental factors predicting meeting MVPA guidelines in young adulthood. RESULTS Overall, 55% of insufficiently active adolescents became young adults meeting MVPA guidelines. On average, participants reported 3.0 hours per week of MVPA, which improved to 3.8 hours per week in young adulthood. Among female participants, higher MVPA in adolescence and stronger feelings of exercise compulsion predicted greater odds of meeting adult MVPA guidelines (odds ratioMVPA = 1.18; odds ratiocompulsion = 1.13). Among female and male participants, perceived friend support for activity in adolescence predicted greater odds of meeting adult MVPA guidelines (odds ratiofemale = 1.12; odds ratiomale = 1.26). CONCLUSIONS Insufficiently active adolescents can later meet adult guidelines. Interventions that increase perceived friend support for activity may benefit individuals across development.