Text Messaging for Exercise Promotion in Older Adults From an Upper-Middle-Income Country: Randomized Controlled Trial
PURPOSE OF THE STUDY To examine the influence of mastery, physical activity levels, and subsequent trajectories of domains of functional health across the adult life course. DESIGN AND METHODS We examined 8-year trajectories of physical functioning (handgrip strength) and functional health (physical [RAND PHC12], psychological [RAND MHC12], and cognitive [processing speed]) in a large Australian sample (n = 7,485 at baseline) of 3 cohorts (20-24, 40-44, and 60-64 years). Within- and between-person indirect effects of physical activity on the relationship between mastery and health were examined using multilevel structural equation models. RESULTS Mastery was positively related to within-person change in physical and psychological health for all cohorts, and processing speed for the 60s. Between-person mastery was positively associated with all health domains across all cohorts. Physical activity indirectly influenced the between-person relationships between mastery and handgrip strength, physical health, and psychological health in all cohorts, and between mastery and processing speed for the 60s. IMPLICATIONS Psychological resources are important mechanisms for functional health as they may drive adaptive behaviors such as physical activity. The within-person association connecting mastery with physical and psychological health trajectories provides promise for interventions that foster or improve a sense of mastery. The findings contribute to the understanding of complex relationships between personal resources and behaviors that aid in successful aging across the life span.