Does autonomous motivation and self-efficacy mediate associations between environmental factors and physical activity in adolescents?

BACKGROUND: To analyze the associations among autonomous motivation, self-efficacy, satisfaction of basic psychological needs, social support and perceived environment with physical activity practice of adolescents aged between 12 and 15 years; and to test autonomous motivations and self-efficacy as potential mediators of the associations between these environmental factors and physical activity practice. METHODS: We evaluated 553 adolescents, that participated in the ActTeens Program. Physical activity was assessed using the Physical Activity Questionnaire for Adolescents. Autonomous motivation, self-efficacy, satisfaction of basic psychological needs, parents' social support and perceived environment were assessed using specifics questionnaires. Linear regression models were used to test the associations. RESULTS: Parents' support (ß = 0.32), satisfaction of basic psychological needs of colleagues (ß = 0.21) and teachers (ß = 0.12), and perceived environment (ß = 0.10) had significant associations with physical activity (p < 0.05). The direct effect value was reduced when autonomous motivation was added as a mediator of the association between parents' support and physical activity (ß = 0.24), with a 25% mediated effect. Autonomous motivation was mediator of the relationship between basic psychological needs of colleagues (ß = 0.13; EM = 38%), teachers (ß = 0.02; EM = 83%), and perceived environment (ß = 0.03; EM = 70%) with physical activity. CONCLUSION: Self-efficacy was not associated with physical activity and autonomous motivation was an important mediator of adolescents' physical activity.

Impact of the ActTeens Program on physical activity and fitness in adolescents: a cluster randomized controlled trial.

BACKGROUND: The aim of our study was to evaluate the impact of the ActTeens Program on physical activity and health-related physical fitness among adolescents in Brazil. METHODS: The "ActTeens Program" was conducted using a cluster-randomized controlled trial during 24-week school term. The sample consisted of 317 adolescents (52.7% girls; 13.61 ± 0.70 years) from four secondary schools that were randomly assigned to intervention group (N = 169) or control group (N = 148). This school-based physical activity (PA) intervention involved two components: (i) structured physical activity sessions delivered within physical education (PE) and (ii) healthy lifestyle guidance (mHealth). The primary outcome was PA assessed using Physical Activity Questionnaire for Adolescents (PAQ-A); secondary outcomes included muscular (MF) and cardiorespiratory fitness (CRF) assessed using 90-push-up, handgrip dynamometer, standing long jump, and 20 m PACER shuttle run test. Assessments were conducted at baseline, 12- and 24-week. Intervention effects were assessed using linear mixed models (LMM). RESULTS: For the primary outcome (PA), no significant group-by-time effects were observed for physical education based-PA (0.3 score; 95%CI: -0.1; 0.6; and - 0.01 score; 95%CI: -0.03; 0.03, at 12-wk and 24-wk respectively) and total PA (-0.02 score; 95%CI: -0.2; 0.2; and - 0.01score; 95%CI: -0.2; 0.2, at 12 and 24 weeks respectively). After 24 weeks, we observed a significant group by time effects for lower body muscular fitness (12.9 cm; 95%CI, 3.2 to 22.2). CONCLUSION: The implementation of aerobic and muscle-strengthening exercises used in the ActTeens intervention did not lead to improvements in physical activity. The intervention resulted in improved lower body muscular fitness, however, we found no significant differences for upper body muscular and cardiorespiratory fitness.