This file was dowloaded from the institutional repository Brage NIH -brage.bibsys.no/nih Riiser, K., Ommundsen, Y., Småstuen, M. C., Løndal, K., Misvaer, N., Helseth, S. (2014). The relationship between fitness and health-related quality of life and the mediating role of self-determined motivation in overweight adolescents.
The relationship between fitness and health-related quality of life and the mediating role of self-determined motivation in overweight adolescentsAim: To examine the relationship between cardiorespiratory fitness (CRF) and health-related quality of life (HRQoL) among overweight adolescents and to test whether this relationship is mediated by body image (BI) and self-determined motivation for physical activity (PA) and exercise. Methods: 120 adolescents identified as overweight or obese were recruited through the school health service. The participants completed self-report instruments measuring HRQoL, BI and self-determined motivation for physical activity and exercise in addition to a 20-m shuttle-run test, and body mass index was calculated. Confirmatory factor analysis was conducted to evaluate the hypothesized fivedimensional structure of the Behavioural regulation in exercise questionnaire-2 (BREQ-2) used to measure self-determined motivation. Associations between the study variables were explored using univariate linear regression. Mediation was tested by a multistage regression approach. Results: The five-dimensional model of BREQ-2 showed acceptable fit for the data. We revealed a statistically significant association between cardiorespiratory fitness and HRQoL (4.16 [0.3-8.02]; p <0.05). CRF failed to affect BI in the first mediation equation, hence body image was excluded from further analyses. However, self-determined motivation proved to mediate the relationship between CRF and HRQoL. Conclusions: The results of this study suggest that the motivational mechanisms related to fitness can contribute to explain the association between CRF and HRQoL in adolescents with overweight. The findings are important from a public health point of view and should be taken into account in the development of PA-interventions for adolescents with overweight and obesity for the potential enhancement of their physical and psychosocial well-being.