Action control in dyads: A randomized controlled trial to promote physical activity in everyday life

Rationale: Engaging in regular physical activity requires substantial self-regulatory effort such as action control (e.g., continuously monitoring and evaluating an ongoing behavior with regard to one's standards). Objective: The present study examined the effectiveness of an ecological momentary action control intervention for promoting daily physical activity. Also, we tested whether a dyadic compared to an individual intervention displayed an additional benefit. Methods: 121 overweight and obese individuals and their partners were randomly allocated to an intervention (n = 60; information + action control text messages) or a control group (n = 61; information only). The intervention was delivered in a dyadic vs. individual version of action control. Allocation ratio was 1:1:2 for the dyadic, individual, and control groups, respectively. Daily physical activity was assessed with triaxial accelerometers during a 14-day intervention phase and a 14-day follow-up phase. Results: Participants in the intervention group showed a higher probability (36.5%) to achieve the recommended daily activity levels (>= 30 min of moderate-to-vigorous physical activity per day performed in bouts of at least 10 min) during the intervention and follow-up phase compared to those in the control group (23.0%). The intervention and control group did not differ in terms of daily moderate-to-vigorous physical activity (40.7 vs. 38.6 min per day, p = 0.623). Conclusion: Interventions facilitating action control via text messages seem to be an effective tool for increasing adherence to physical activity guidelines in everyday life. The comparable effects for the dyadic and individual intervention suggest that automated text messages may be just as effective as personalized messages from the romantic partner. Further investigation is needed to examine the usefulness of a dyadic conceptualizing of action control. (controlled-trials.com ISRCTN15705531). (C) 2016 Elsevier Ltd. All rights reserved.