Abstract
BACKGROUND: Cutting-edge dual process health behavior theories propose micro-temporal within-person processes to be critical drivers of physical activity participation. Self-efficacy is the pivotal motivation-oriented correlate of physical activity, a key component across the most prominent health behavior change theories, and has predominantly been researched as stable interpersonal 'trait' factor. However, the micro-temporal within-person 'state' perspective on self-efficacy remains uncharted. OBJECTIVES: To tackle this research gap, we conducted a scoping review and examined (1) time-sensitive (i.e., assessment time span) and (2) theory-conform operationalization of self-efficacy measures as well as (3) within-person variance reports from ecological momentary assessment studies in the physical activity context among healthy adults. METHODS: A scoping review of English articles using PsycINFO, PsycArticles, PSYNDEX, SPORTDiscus and PubMed was conducted up to September 2025. Eligible studies focused on (1) physical activity in (2) healthy adults aged + 18 years and (3) applied multiple within-day, daily or weekly assessments of self-efficacy. Findings were summarized through quantitative analysis of the evidence. RESULTS: A total of 13 studies was included. Most studies assessed self-efficacy through multiple assessments per day and with a focus on the near future (i.e., next few hours post ecological momentary assessment). The 13 identified self-efficacy items were operationalized according to self-efficacy theory, but varied in semantics, psychometrics, and source. Five studies reported intraclass correlation coefficients that revealed self-efficacy within-person variance to range between 51% and 89%. CONCLUSIONS: Given the pivotal role of self-efficacy across various health-behavior theories and the recent relevance attributed to micro-temporal within-subject processes, thus far surprisingly few studies researched how self-efficacy unfolds within-persons across time. However, the few studies identified provide initial evidence that self-efficacy varies within individuals across time in everyday life, including a tendency towards higher within-person variance for momentary versus day level assessments, and thereby empirically supporting dual process models. Items were assessed dynamically using repeated measures per day and according to theory but differed in conceptual and semantic features. Future research is encouraged to further investigate how self-efficacy unfolds across time, by testing various sampling strategies and applying advanced designs to shed light on the precise timing of effects and to inform adaptive and expedient intervention development.