Does action planning moderate the intention-habit interaction in the exercise domain? A three-way interaction analysis investigation

Both habit strength and action planning have been found to moderate the intention-exercise behaviour relationship, but no research exists that has investigated how habit strength and action planning simultaneously influence this relationship. The present study was designed to explore this issue in a prospective sample of undergraduate students (N = 415): action planning, habit strength, intention, attitudes, subjective norms and perceived behavioural control were assessed at baseline and exercise behaviour was assessed 2 weeks later. Both habit strength and action planning moderated the intention-exercise relationship, with stronger relationship at higher levels of planning or habit strength. Decomposing a significant action planning x habit strength x intention interaction showed that the strength of the intention-exercise relationship progressed linearly through levels of action planning and habit strength. These novel results show that action planning strengthens the intention-habit strength interaction in the exercise domain: exercise interventions should therefore focus on simultaneously bolstering action planning and habit strength.