Do brief online planning interventions increase physical activity amongst university students? A randomised controlled trial

Brief planning interventions, usually delivered within paper and pencil questionnaires, have been found to be effective in changing health behaviours. Using a double-blind randomised controlled trial, this study examined the efficacy of two types of planning interventions (action plans and coping plans) in increasing physical activity levels when they are delivered via the internet. Following the completion of self-reported physical activity (primary outcome) and theory of planned behaviour (TPB) measures at baseline, students (N = 1273) were randomised into one of four conditions on the basis of a 2 (received instructions to form action plans or not) × 2 (received instructions to form coping plans or not) factorial design. Physical activity (primary outcome) and TPB measures were completed again at two-month follow-up. An objective measure (attendance at the university's sports facilities) was employed 6 weeks after a follow-up for a duration of 13 weeks (secondary outcome). The interventions did not change self-reported physical activity, attendance at campus sports facilities or TPB measures. This might be due to low adherence to the intervention protocol (ranging from 58.8 to 76.7%). The results of this study suggest that the planning interventions under investigation are ineffective in changing behaviour when delivered online to a sample of participants unaware of the allocation to different conditions. Possible moderators of the effectiveness of planning interventions in changing health behaviours are discussed