[Perceptions and external factors of physical activity in adolescents using mixed methods].

OBJECTIVE:Analyze the levels of physical activity in adolescents and their relationship with perceptions of physical activity and external factors. METHOD:Cross-sectional descriptive observational study. The participants were adolescents between the ages of 11 and 18. They were recruited in secondary schools in the municipality of Esplugues de Llobregat, Barcelona, Spain. The measurements were amount of physical activity (IPAQ-A questionnaire) and the relationship between level of physical activity and the perceptions of physical activity and external factors proposed by the health promotion model. RESULTS:Of the total sample, 60.34% participants were insufficiently active. The factors positively associated with physical activity were male gender (p<0.01), engaging in extracurricular sports (p<0.01), perceiving benefits (p<0.01), perceiving self-efficacy (p<0.01), interpersonal influences (p<0.01), having parents who engage in sports (p<0.01), social support (p<0.01) and social norms supporting exercise (p<0.01). The factors negatively associated with physical activity were female gender (p<0.01), body mass index (p=0.048) and perceiving obstacles (p<0.01). There was no relationship with social class (p=0.164). Situational influences were a conditioning factor for boys (p<0.01), but not girls (p=0.561). CONCLUSIONS:This study identifies factors that determinate the practice of physical activity in adolescents. Taking these factors into account in the design of health promotion interventions and policies could help increase levels of physical activity in this population. Even so, there are some variables, such as gender and socioeconomic status, that should be explored in depth through research that is more exploratory and discursive.