Reinforcing implementation intentions with imagery increases physical activity habit strength and behaviour

Abstract

Objectives: Habits may enhance the maintenance of physical activity. The aim of this study is to examine if reinforcing implementation intentions increases habit strength and thus physical activity. Design: Participants (N = 186) were randomized into one of three intervention conditions (imagery vs. implementation intentions vs. combined; implementation intentions and imagery) and a control condition. Methods: Participants were instructed to engage in a physical activity that they would like to start doing, or do more of, over a four-week period. Participants completed measures of physical activity, habit strength, and imagery use (imagery and combined conditions only) pre-intervention, weekly during the intervention, post-intervention, and a 12-week follow-up. Results: Habit strength increased at week three (p.05). In the imagery condition, habit strength increased at post-intervention (p =.003) and was maintained at follow-up. Physical activity increased for the combined condition from week two (p