Exploring the mechanism of change in exercise behavior during a theory-based exercise intervention among community-dwelling (pre)frail older adults: A stepped wedge cluster randomized trial.

This study evaluated the effectiveness of a theory-based exercise intervention on exercise beliefs and behavior, and clarified the underlying mechanism of the exercise intervention among community-dwelling (pre)frail older adults. A 12-week exercise intervention based on the integration of Health Belief Model, Theory of Planned Behavior and Health Action Process Approach was implemented to 149 participants. The positive effects were significant on exercise beliefs (β = -1.630 - 3.500, P < 0.05) and exercise behavior (β = 0.851, P < 0.001), and most of them persisted at 12- and 24-week postintervention. Furthermore, perceived barriers (ββ = 0.118, P = 0.037) and descriptive norms (ββ = 0.144, P = 0.047) mediated the relationship between exercise intervention and exercise behavior. The theory-based exercise intervention improves exercise beliefs and behavior, and perceived barriers and descriptive norms play a crucial role in increasing exercise behavior among the target population.