Abstract
INTRODUCTION: Physical activity (PA) is essential for healthy aging, yet participation declines as older adults face interacting social, environmental, motivational, and functional barriers. Existing research rarely integrates these determinants to explain how context and capability shape PA behavior. METHODS: This study examined the mechanisms linking environmental opportunity, social support, motivation, and capability to PA among community-dwelling older adults using an integrated framework grounded in Self-Determination Theory (SDT), the COM-B model, and social-ecological principles. The English Longitudinal Study of Ageing (ELSA) was an adult study (3,842 adults aged 60 years and above) that collected data. Interventions were PA, social support, community involvement, environmental opportunity, motivational constructs (autonomy, competence, self-efficacy, identity), and functional capability. Descriptive statistics, correlation analysis, and structural equation modeling (SEM) were performed, along with tests of mediation and moderation. RESULTS: The most significant predictors of moderate and vigorous PA were motivation. The effects of environmental opportunity and social support were mainly indirect, through motivation, and the motivation pathways explained 56-63% of the overall impact. The relationships were strongly moderated by capability: the motivational effects were more pronounced among those with fewer functional limitations. The sensitivity analysis proved the soundness of the integrated model. DISCUSSION: PA in old age represents the product of an active interaction between motivational, social, environmental, and capability-related aspects. The core route from external conditions to behavior comprises motivational processes, and the magnitude of motivation to act is determined by capability. Motivational strengthening, the supportive environment, and customized capability plans should be combined into effective interventions to facilitate active aging.