Matched or nonmatched interventions based on the transtheoretical model to promote physical activity.A meta-analysis of randomized controlled trials

Purpose: The aim of this study was to examine whether the efficacy of transtheoretical model(TTM)-based interventions on physical activity(PA)varied according to the following criteria:(1) interventions targeted the actual stages of change(SOCs) or did not;(2) participants were selected according to their SOC or were not; and(3) its theoretical constructs(decisional balance, temptation, self-efficacy, processes of change).Methods: Thirty-three randomized controlled trials assessing TTM-based interventions promoting PA in adults were systematically identified.Results: The between-group heterogeneity statistic(Qb) did not reveal any differential efficacy either in interventions targeting the actual SOC compared with those that did not(Qb = 1.48, p = 0.22) or in interventions selecting participants according to their SOC compared with those that did not(Qb = 0.01, p = 0.91). TTM-based interventions enhanced PA behavior whether they targeted the actual SOC(Cohen's d = 0.36; 95%confidence interval(CI): 0.22–0.49) or not(d = 0.23; 95%CI: 0.09–0.38) and whether they selected their participants according to their SOC(d = 0.33; 95%CI: 0.13–0.53) or not(d = 0.32; 95%CI: 0.19–0.44). The moderators of the efficacy of TTM-based interventions were the number of theoretical constructs used to tailor the intervention(Qb = 8.82, p = 0.003), the use of self-efficacy(Qb = 6.09, p = 0.01), and the processes of change(Qb = 3.51, p = 0.06).Conclusion: TTM-based interventions significantly improved PA behavior, and their efficacy was not moderated by SOC but by the TTM theoretical constructs.