Biocultural approach of the association between maturity and physical activity in youth.

Objective: To test the biocultural model through direct and indirect associations between biological maturation, adiposity, cardiorespiratory fitness, feelings of sadness, social relationships, and physical activity in adolescents.

Methods: This was a cross-sectional study conducted with 1,152 Brazilian adolescents aged between 10 and 17 years. Somatic maturation was estimated through Mirwald's method (peak height velocity). Physical activity was assessed through Baecke questionnaire (occupational, leisure, and sport contexts). Body mass index, body fat (sum of skinfolds), cardiorespiratory fitness (20-m shuttle run test), self-perceptions of social relationship, and frequency of sadness feelings were obtained for statistical modeling.

Results: Somatic maturation is directly related to sport practice and leisure time physical activity only among girls (β=0.12, p<0.05 and β=0.09, respectively, p<0.05). Moreover, biological (adiposity and cardiorespiratory fitness), psychological (sadness), and social (satisfaction with social relationships) variables mediated the association between maturity and physical activity in boys and for occupational physical activity in girls. In general, models presented good fit coefficients.

Conclusion: Biocultural model presents good fit and emotional/biological factors mediate part of the relationship between somatic maturation and physical activity.