Sex and educational level differences in physical activity and motivations to exercise among Spanish children and adolescents.

Children and adolescents worldwide, especially girls, do not meet moderate to vigorous physical activity (MVPA) guidelines, a situation which is related to obesity and other comorbidities. Sex/gender differences in the practice of MVPA and motivations to engage in physical activity have not been previously examined among Spanish students considering different educational levels. Therefore, the purpose of this study was to explore these differences and analyse if motivations mediate the relationship between educational levels and MVPA in a large sample of students. From different schools in the Madrid region (primary: 11,122; lower secondary: 12,379; upper secondary: 3228) 26,729 students (13,491 boys and 13,238 girls; 9-19 years old) were recruited to participate in this study. The short form of the International Physical Activity Questionnaire and the third version of the Behavioural Regulation in Exercise Questionnaire were used to evaluate, MVPA and motivations to exercise, respectively. Two-way ANCOVA and a mediation analysis were performed. Female students were found to be less active than males (43.4±38.7 and 58.6±45.9 min of MVPA; p < 0.001; η = 0.023) and showed lower intrinsic (η = 0.003), and integrated (η = 0.007) motivations than their male counterparts (p < 0.001). Primary school students were more active than lower and upper secondary students (53.3±44.2, 49.9±42.3 and 48.0±42.8 min of MVPA; p < 0.001; η = 0.002) and also presented higher intrinsic (η = 0.011) and integrated (η = 0.010) motivation than secondary school students (p < 0.001).    Conclusion:   Among Spanish children and adolescents, females showed lower levels of MVPA and intrinsic and integrated motivation across all the educational levels, and among primary school students in comparison to secondary school. This suggests that inner motivation is more determinant of increased engagement in MVPA and thus, there is need to reinforce it before the transition to secondary school and with special focus on females' preferences. What is Known: •Many children and adolescents worldwide, do not meet physical activity (PA) recommendations. • Within the self-determination theory, autonomous motivation seems to be the main responsible of greater PA levels. What is New: •This study shows for the first time sex and educational level differences in PA levels in a representative sample of Spanish students (9-19 yrs). •Autonomous motivation decreased from primary school onwards and was lower in female students than in their male counterparts.