Revisiting the Transtheoretical Model for Physical Activity: A Large-Scale Cross-Sectional Study on Japanese-Speaking Adults

Background The Transtheoretical Model (TTM) has been the basis of health promotion programs, which are, for example, used to tailor behavioral interventions according to the stages of change. Empirical studies have shown that the TTM effectively describes the processes of behavioral adaptation to acquire healthier lifestyles; however, it has been argued that TTM-based interventions are not superior to non-TTM-based interventions for promoting physical activity (PA). Evidence has also highlighted some inconsistencies with theoretical assumptions, especially regarding how each process-of-change strategy emerges across the stages.Purpose Therefore, we investigated (a) how well the TTM describes the distributional characteristics of PA levels as well as other relevant variables (e.g., process of change, self-efficacy) across stages, and (b) how predictive the TTM variables are of PA levels within each stage.Methods We analyzed data from 20,573 Japanese-speaking adults who completed online questionnaires on PA and TTM variables.Results The results replicated previous findings that stage membership is associated with PA, the process of change, decisional balance, and self-efficacy, albeit with inconclusive evidence of temptations. Regression analyses revealed that some processes of change (self-reevaluation, reinforcement management, and self-liberation) were more predictive of PA in pre-active stages than in post-action stages; self-efficacy was predictive of PA only in the maintenance stage but not in the other stages.Conclusions Overall, the data support the theoretical assumptions of the TTM, but the stage specificity of the active processes may not always be consistent with the theory. The Transtheoretical Model has been the basis of many behavioral interventions for promoting physical activity. One of the key concepts of the model is the stage of change, which is a framework to help understand the readiness to begin physical activity and exercise. The model assumes five progressive stages of behavior change (e.g., the precontemplation stage, where people have no intention to change behavior; the maintenance stage, where people have continued physical activity for a long enough period), through which individuals acquire an active lifestyle. The model also assumes that different strategies for behavior change are appropriate at different stages and, confidence and attitudes toward physical activity vary dynamically across stages. The current study examined how valid these theoretical assumptions using data from 20,573 Japanese-speaking adults. The data overall supported the assumptions of the Transtheoretical Model, for example, highlighting the importance of enhancing awareness about the causes and (dis)advantages of being (in)active at earlier stages. Although some inconsistencies were identified (some strategies were not as useful as the model assumed), these findings may suggest that the Transtheoretical Model holds universal theoretical value as a descriptive model of behavioral change for active lifestyle across Western and East Asian populations.