The Transtheoretical Model (Prochaska, DiClemente, & Norcross, 1992) has been used to conceptualize the process of intentional behavior change. The Model may be thought of as a cycle of distinct cognitive markers that describe five unique Stages of Change. The five stages are Precontemplation, Contemplation, Preparation, Action and Maintenance. Transition among stages results from experiential and behavioral processes that the individual may experience called the Processes of Change. Each of these stages are characterized by changes in decisional balance; that is, the balance between benefits and costs associated with engaging in a particular behavior.
Precontemplation describes the stage where one is not considering changing a particular behavior. In staging physical activity, this person would be inactive and not considering becoming active any time in the foreseeable future. An individual enters the stage of Contemplation when he or she becomes aware of a desire to change a particular behavior. This stage likely describes a number of sedentary citizens in the United States, who think about being active, but lack sufficient commitment to change their behavior. The Preparation stage of the Model indicates not only a desire to change, but also evidence of commitment to make that change in the near future, traditionally within the next 30 days. Someone in the Preparation Stage of Change for regular, moderate physical activity might seek information describing regular activity, make a few phone calls pricing local gyms, or rally verbal support from friends and colleagues for a lunchtime activity plan.
The Action stage is where the change in the criterion behavior actually occurs. Progressing through this stage may include intense effort to modify behavior itself as well as the environment in which the behavior occurs, and is expected to endure for about six months. When considering physical activity, Action may mean changing routines, reallocating time, and developing strategies to cope with the many environmental barriers to engaging in physical activity. The fifth Stage, Maintenance, consists of ongoing change of the target behavior; however, individuals are often faced with preventing relapse back to an earlier stage. The seasonal climate changes in many parts of the United States provide a good example of how relapse may be difficult to prevent during Maintenance. In the summertime, the temperature is warm and the days are long, facilitating outdoor activity. As the days grow colder and shorter, maintaining levels of activity may pose a challenge to those who have few indoor facilities at their disposal. Even with the best of intentions, preventing relapsing back to a sedentary lifestyle may be quite difficult. Focusing on the many benefits of and gains from the behavior change may help to combat relapse during Maintenance.
Decisional balance (Janis & Mann, 1977) changes as individuals make their way through the Stages of change. The decisional balance that a person feels may be thought of as a balance between the benefits and the costs associated with the particular target behavior. While in reality progress through the Stages is not linear, and people may progress and recess among the stages, for the purposes of this discussion, it is useful to consider the Stages along a continuum starting with Precontemplation, progressing through Contemplation, Preparation and Action, and ending with Maintenance. As one transits through these stages, her or his decisional balance shifts too. During precontemplation, one may weigh in more heavily on the side of the cons toward a particular behavior. As one become conscious of the desire for change, the decisional balance becomes less unipolar. During the transit between Preparation and Action, the pros associated with the behavior change outweigh the cons on the decisional balance. As one proceeds into Maintenance, it is important to keep the decisional balance securely weighted in favor of the pros associated with the behavior change, otherwise one increases the risk of relapse.