Effects of transtheoretical model of change-based interventions on physical activity among older adults: a systematic review of randomised controlled and non-randomised controlled trials.

backgroundPhysical inactivity in older adults is a major public health concern associated with numerous non-communicable chronic conditions. Several behaviour theories have been advanced to address the issue of physical inactivity including Transtheoretical Model (TTM) of Change among older adults. The study aimed to primarily assess the cumulative effect of TTM-based interventions on physical activity and secondarily on self-efficacy among older adults.

methodsA systematic search of electronic databases (including Cochrane Library, AgeLine, Medline, Scopus, PsycINFO, and Web of Science Core Collections) was searched from inception to August 2024. Inclusion criteria comprised studies investigating TTM-based interventions on PA in individuals aged 60 and above, randomised controlled trials (RCTs) and non-RCTs. Risk of bias was assessed using Cochrane Collaboration's tool for RCTs while ROBIN-I was used for non-RCTs. The Grading of Recommendations Assessment, Development and Evaluation was used to evaluate the certainty of the evidence. Study findings were narratively synthesised in line with the Synthesis Without Meta-analysis framework.

resultsThree studies (two RCTs and one non-RCT) met the inclusion criteria, comprising 1,474 participants (65-89 years; 71% females). TTM interventions showed low certainty of evidence of no significant effects on physical activity or self-efficacy for the RCTs. In contrast, the non-RCT showed very low-certainty evidence for the significant effects of TTM on physical activity among participants in the under-maintenance and maintenance stages, with long-term benefits limited only to those already in the maintenance stage. For self-efficacy, there was very low certainty of evidence for the significant effects of TTM only among participants in the under-maintenance stage.

conclusionThis review highlights the limited, inconsistent and low level of evidence of the effects of TTM-based interventions in promoting physical activity among older adults. Whilst for self-efficacy, there is limited, mixed and low to very low level of evidence for the beneficial effects of TTM interventions. More RCTs are needed to identify the most effective components of the TTM and understand the impact of different intervention delivery methods (e.g., digital versus face-to-face) for physical activity promotion in the older adult population.