Post-intervention durability of standalone digital behavior change interventions for physical activity in adults: a focused mini review and quantitative synthesis.

BACKGROUND: Standalone digital behavior change interventions (DBCIs) are increasingly used to promote physical activity (PA), but their post-intervention durability remains unclear. This focused mini review with quantitative synthesis examined maintenance and attenuation of standalone DBCI effects on PA in adults. METHODS: PubMed, Web of Science Core Collection, and SPORTDiscus were searched without date restrictions, with the final search conducted on 3 May 2026. Eligible studies were randomized controlled studies involving adults, standalone DBCIs targeting PA, a comparator not receiving the target structured DBCI, and PA outcomes assessed post-intervention and at ≥1 follow-up. Random-effects meta-analyses used Hedges' g, with the longest follow-up used for the primary maintenance analysis. RESULTS: Seventeen studies involving 8,990 participants were included in the review, of which 13 contributed effect sizes to the primary quantitative synthesis. Standalone DBCIs showed a small, non-significant effect at the longest follow-up (g = 0.13; p = 0.066; I 2 = 64.2%), with low-certainty evidence. Time-window analyses showed a small significant post-intervention effect (g = 0.14; p = 0.048), whereas follow-up effects were small and non-significant. Meta-regression showed no clear progressive attenuation. CONCLUSION: Standalone DBCIs showed small positive post-intervention point estimates, but evidence remains insufficient to establish reliable maintenance after active support is reduced or withdrawn. Future studies should use repeated follow-ups and report engagement, continued tool access, and post-intervention support.