This study used a prospective design to test a model of the relation between social cognitive variables and physical activity in a sample of 277 university students. Social support, self-efficacy, outcome expectations, and self-regulation were measured at baseline and used to predict physical activity 8 weeks later. Results of structural equation modeling indicated a good fit of the social cognitive model to the data. Within the model, self-efficacy had the greatest total effect on physical activity, mediated largely by self-regulation, which directly predicted physical activity. Social support indirectly predicted physical activity through its effect on self-efficacy. Outcome expectations had a small total effect on physical activity, which did not reach significance. The social cognitive model explained 55% of the variance observed in physical activity.

Health professionals have begun using social media to benefit patients, enhance professional networks, and advance understanding of individual and contextual factors influencing public health. However, discussion of the dangers of these technologies in medicine has overwhelmed consideration of positive applications. This article summarizes the hazards of social media in medicine and explores how changes in functionality on sites like Facebook may make these technologies less perilous for health professionals. Finally, it describes the most promising avenues through which professionals can use social media in medicine – improving patient communication, enhancing professional development, and contributing to public health research and service.

Theoretical fidelity could advance the quality of physical activity interventions, which have often shown small effects.

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