Mediators and moderators of maintenance of physical activity behaviour change: a systematic review

Abstract

Background: Adults should undertake 150 minutes of moderate physical activity (PA) weekly for reduced risk of non-communicable disease. Physical inactivity levels are high, calling for effective methods of maintaining PA behaviour. Interventions are limited in achieving PA maintenance, and causal mechanisms are poorly understood. This review investigated potential mediators and moderators for maintained PA behaviour. Methods: Six databases were searched (Medline, EMBASE, PsycINFO, CINAHL, Cochrane, Web of Science). Search terms: ‘Physical activity’, study design, ‘behaviour change’, ‘maintenance’. Eligibility criteria: adults; non-clinical; validated PA measure at baseline and 6 months (maintenance); comparison group. Mediators were separated according to studies testing effect on the mediator, association with PA, or carrying out formal mediation tests. Number of studies, tests and percentage significant effects were reported. Moderators were separated according to subgroup analyses or formal tests. Number of studies and percentage significant effects were reported. Findings: 57 studies were included (26 examined mediators, 18 examined moderators). 49 mediators were categorised using the Theoretical Domains Framework. Variables with strongest empirical support in formal mediation tests were: revitilisation (passing 4/4 tests), self-concept (1/1), behavioural processes of change (6/7), positive intentions (2/4), self-regulation (1/2). 18 variables were used in moderator tests. These focused on demographic variables but environmental accessibility showed potential (one study favoured high access). Discussion: Formal mediation tests should have theoretical justification. Assessments should incorporate longer timeframes and relevant maintenance constructs such as habit, coping planning, recovery self-efficacy or outcome satisfaction. Consideration of the interplay between mediators and moderators should lead to theoretical developments.