Action Planning and Mental Imagery to Reduce Sedentary Behavior in Older Adults: A Full Factorial Randomized Trial

Prolonged sedentary behavior increases the risk of noncommunicable diseases, making older adults an important target for interventions. Although action planning is a commonly used behavior change technique to reduce sedentary behavior, findings on its effectiveness in older adults remain inconclusive. This study investigates whether mental imagery enhances the effectiveness of action planning in reducing sedentary behavior in older adults. To explore this, a 2×2 full factorial randomized trial with an intensive longitudinal design will be conducted, crossing the factors action planning (yes/no) and mental imagery (yes/no). A total of 160 participants aged 70 years and older will be randomly assigned to one of four experimental conditions. Sedentary behavior will be assessed objectively using accelerometry, and relevant psychological variables will be captured via self-report over a 21-day period. The intervention will take place on Day 8, followed by a booster session on Day 15. Main and interaction effects on primary and secondary outcomes will be analyzed. notReviewed other