Programa de Intervenção Escolar na Atividade Física: desenho, implementação e efeitos do programa em adolescentes.

Abstract

Introduction: Physical activity behavior at pediatric ages is the object of concern of different health organizations, given the close relationship with chronic noncommunicable diseases. The promotion of this behavior is decisive, and the school, for all its strengths, presents itself as an election body to fulfill this role. Aim: To design a socio-ecological school-based intervention, called "Program of Physical Activity and Nutrition for Adolescents" and to evaluate its impact on physical activity behavior and other health indicators in children and adolescents from Madeira Island. Methods: A randomized controlled trial with a multicomponent intervention - 15 months, followed by 15 months of follow-up (without any intervention). The study involved, at baseline, 2124 participants from eight public schools, allocated to an experimental group (4 schools) and control group (4 schools). Physical activity, cardiorespiratory fitness, anthropometric indicators, psychosocial variables and physical environment were evaluated in the three moments. Two qualitative studies were developed: i) with 16 focus groups (92 young people) in which the thematic analysis allowed to identify factors related to physical education, intervals and school sports that influence the behavior of physical activity; ii) semi-structured interviews, with eight teachers from intervention schools, whose thematic analysis presented three categories that allowed to evaluate the implementation. The translation, adaptation and validation of three questionnaires were performed. Adjustments for school, sex, age, and outcome at baseline were made. Results: Translated and adapted questionnaires showed satisfactory validity and reliability. Participants in the focus group indicate that changes in social, physical and political school environment could make physical activity more appealing in different school contexts. The results of the cross-sectional study showed that individual factors (sex, sports experience and pleasure / satisfaction in practice) explained 19.3% of the variance of physical activity levels among the young (p <0.001) and social and involvement determinants explain 7.3% and 0.6%, respectively. The program showed positive effects on physical activity (p = 0.017), percentage of fat mass (p <0.001) and determinants of physical and social environment in school for physical activity (p <0.05). Conclusion: This school-based intervention was adequate in change physical activity behaviors and other determinants of this behavior. The perspective of the receivers (students) and the applicators (teachers) should always be considered in the definition of intervention strategies in a school context. Key words: physical activity, school, environment, intervention, health promotion, adolescents