Ecological momentary assessment of social context and physical activity: a systematic review

Abstract Background Physical activity is shaped by social context, yet most research relies on retrospective, cross-sectional measures that cannot capture the moment-to-moment social dynamics of daily life. Ecological momentary assessment (EMA) offers a methodologically distinct approach, enabling real-time, repeated measurement of social context and physical activity in naturalistic settings. This systematic review synthesized EMA research examining associations between social context and physical activity across operationalizations. Methods A systematic search of four databases (PubMed, PsycINFO, Web of Science, SPORTDiscus/CINAHL) yielded 3,731 records. Following deduplication and title/abstract screening, 76 full-text articles were reviewed, and 29 studies meeting all eligibility criteria were included. Eligible studies required a real-time or near real-time repeated measure of social context, a physical activity outcome, and an analysis of the association between the two. Data were extracted on study design, population characteristics, physical activity and social context measures, EMA protocol, and key findings. Methodological quality was assessed using the NHLBI Quality Assessment Tool for Observational Cohort and Cross-Sectional Studies. Results Included studies employed distinct operationalizations of social context: companion presence, companion identity, social support, interaction frequency and quality, social tie diversity, and perceived social barriers. Samples spanned children through older adults and included clinical and community populations. Social support showed positive associations with physical activity. Peer and friend presence was more consistently associated with activity than family presence across the lifespan. Within- and between-person effects frequently diverged; in some samples, individuals were more active at moments when alone, yet those who spent more time alone overall were less active on average. Associations further varied by behavior change phase, relationship type, and affective response. Social tie diversity and positive interaction quality showed promising associations with activity, while social barriers and weight management-focused support did not. Conclusions Associations between social context and physical activity appear dynamic and situationally contingent rather than reflecting a stable facilitative resource. These findings underscore the value of EMA designs for identifying within-person processes that cross-sectional methods obscure, and support the development of time-specific, socially-informed interventions, particularly micro-randomized and just-in-time adaptive approaches, that account for relationship type, support dimension, and behavior change stage.