This study tested the predictive validity of a multitheory process model in which the effect of autonomous motivation from self-determination theory on physical activity participation is mediated by the adoption of self-regulatory techniques based on control theory. Finnish adolescents (N = 411, aged 17–19) completed a prospective survey including validated measures of the predictors and physical activity, at baseline and after one month (N = 177). A subsample used an accelerometer to objectively measure physical activity and further validate the physical activity self-report assessment tool (n = 44). Autonomous motivation statistically significantly predicted action planning, coping planning, and self-monitoring. Coping planning and self-monitoringmediated the effect of autonomous motivation on physical activity, although self-monitoring was the most prominent. Controlled motivation had no effect on self-regulation techniques or physical activity. Developing interventions that support autonomous motivation for physical activity may foster increased engagement in self-regulation techniques and positively affect physical activity behavior.
Johanna Nurmi is with the Department of Social Research, Faculty of Social Sciences, University of Helsinki, Finlandand the Helsinki Institute for Information Technology (HIIT), Finland. Martin S. Hagger is with the Laboratory of Self-Regulation and Health Psychology and Behavioral Medicine Research Group, School of Psychology and Speech Pathology, Faculty of Health Sciences, Curtin University, Perth, Australia; the School of Sport Sciences, Faculty of Sport and Health Sciences, University of Jyväskylä, Jyväskylä, Finland; and the School of Applied Psychology and Menzies Institute for Health Queensland, Griffith University, Mt. Gravatt, Brisbane, Queensland, Australia. Ari Haukkala is with the Department of Social Research, Faculty of Social Sciences, University of Helsinki, Finland. Vera Araújo-Soares is with the Institute of Health and Society, Faculty of Medical Sciences, Newcastle University, UK. Nelli Hankonen is with the Department of Social Research, Faculty of Social Sciences, University of Helsinki, Finland, and the School of Social Sciences and Humanities, University of Tampere, Finland.