What is the relationship between family closeness, social support, and adolescent physical activity? Evidence from longitudinal tracking

(1) Significant gender differences exist in family closeness, social support, and physical activity among children and adolescents; (2) Family closeness and social support are positively correlated with adolescent physical activity; (3) Within the adolescent cohort, family closeness and social support cross-predict physical activity over time, while social support and physical activity also cross-predict each other over time.