Are action planning and physical activity mediators of the intention habit relationship?

Objectives: Physical activity is associated with many health benefits that are important for older adults. These health benefits can only be obtained and preserved when physical activity is maintained over a long period of time. Habit formation has been proposed as a way to ensure long-term maintenance of physical activity. Intention, action planning, and physical activity are suggested to be determinants of physical activity habits. However, how they determine physical activity habits in older adults is largely unknown. This study examined whether the relationship between intention and habit is mediated by action planning and/or physical activity. Design: A four-wave prospective design was used. Methods: Two independent studies were conducted in 469 (Study 1; M-age = 63.07, SDage = 7.61) and 322 (Study 2; M-age = 64.31, SDage = 9.39) older adults. Study 2 was conducted with the aim of replicating findings of Study 1. In both studies the older adults completed questionnaires on intention, physical activity, and habit at baseline, action planning at three months, physical activity at six months, and habit at twelve months. Results: Structural equation modeling analyses showed significant intention-physical activity-habit paths, nonsignificant intention-action planning-habit paths, and nonsignificant intention-action planning-physical activity-habit paths in both studies. Conclusions: The relationship between physical activity habit and intention was mediated by physical activity. Intention was neither associated with habit via action planning as a single mediator, nor via action planning and physical activity as sequential mediators. Possible conditions under which intention action planning-habit paths and intention-action planning-physical activity-habit paths exist are discussed.