Mental Contrasting With Implementation Intentions

Abstract: Background: Physical activity interventions can promote a more active lifestyle. Previous findings on the effects of such interventions for working adults are mixed. Aims: The main goal of this study was to examine an online physical activity intervention for working adults, building on the theoretical approach of mental contrasting with implementation intentions (MCII). Method: Participants ( N = 336) were randomly assigned to an MCII intervention and a control group. Intervention group participants completed an initial online MCII intervention and daily morning refreshers over 10 workdays. Participants reported their moderate-to-vigorous physical activity (MVPA) in daily diaries and at a 6-month follow-up. Results: The intervention resulted in mixed findings. Multi-level path analysis showed that daily refreshers were effective in predicting same-day MVPA. However, control group participants reported more after-work MVPA during the daily-diary period, although intervention group participants successfully completed the initial intervention. In the overall sample, MVPA during the daily-diary phase predicted MVPA at follow-up, even when controlling for baseline physical activity and baseline self-efficacy. Limitations: The overall complex intervention might have imposed too much of a burden on working adults in the intervention group. The generalizability of our findings might be limited. Conclusion: Morning refreshers help to be physically active, but control group participants can also benefit from study participation when survey questions serve as reminders for being physically active.