General Self-Efficacy as a Mediator of Physical Activity’s Impact on Well-Being Among Norwegian Adolescents: A Gender and Age Perspective

Background: The mechanisms behind the beneficial effects of physical activity on adolescent well-being remain poorly understood. One potential pathway involves increased general self-efficacy. A deeper understanding of underlying processes, and of direct and indirect impacts across adolescent sub-groups, can improve intervention strategies. This study investigates whether physical activity predicts subjective well-being in adolescents, the mediating role of general self-efficacy, and the moderating effect of gender and age on these relationships. Methods: This cross-sectional survey study utilised data from a population-based sample of 18,146 Norwegian adolescents aged 14–19. Simple and moderated mediation models were tested with Hayes’ PROCESS in SPSS, with life satisfaction as the dependent variable, physical activity as the independent variable, general self-efficacy as the mediator, and gender and age as moderators. Analyses were controlled for socio-demographic variables and social support. Results: The findings indicated a small, positive effect of physical activity on well-being, consistent across genders but increasing with age, though not significant for those under 14.5 years. Approximately half of the total effect of physical activity on well-being was mediated through general self-efficacy. This indirect effect was greater for girls and younger adolescents compared to their counterparts, due to greater positive impacts of general self-efficacy on well-being within these two sub-groups. Conclusions: By identifying general self-efficacy as a mediator of physical activity’s impact on adolescent well-being, along with distinct direct and indirect effects within sub-groups, this study enhances the theoretical framework and knowledge base for more effective physical activity initiatives targeting the well-being of this demographic.