Motivational interviewing and self-determination theory in a web-based computer tailored physical activity intervention: A randomized controlled trial

Objective: This study explores whether a web-based physical activity (PA) intervention grounded in self-determination theory(SDT) and motivational interviewing (MI) is more effective and better appreciated than a traditional web-based PA intervention.Design: A randomized controlled trial was conducted, comparing (1) I Move; a web-based PA intervention based on SDT and MI, (2) Active Plus; a traditional web-based PA intervention and (3) a waiting list control condition.Main outcome measures: Weekly minutes of moderate to vigorous PA and weekly days with30 min PA were measured through self-report at baseline and at 3 and 6months from baseline.Results: I Move achieved a small, but significant increase in weekly minutes of moderate to vigorous PA, while Active Plus did not have a significant impact on this outcome. Both interventions were effective in increasing weekly days with30 min PA, whereas Active Plus yielded a greater effect on this outcome.Conclusion: Overall, the web-based PA intervention grounded in SDTand MI did not outperform the traditional web-based PA intervention. Further research should reveal whether this type of intervention is profitable for long-term maintenance of PA levels