Effect of Episodic Future Thinking on Promoting Physical Activity Among Older Adults With Motoric Cognitive Risk Syndrome: A Randomized Controlled Trial

Behavioral intention toward physical activity was assessed using the Behavioral Intention subscale of the Theory of Planned Behavior Exercise Questionnaire developed by Hu et al. Participants rated three items (e.g., their acceptance, intention, and plan to engage in ≥3 sessions of ≥20 minutes of exercise per week over the next four weeks) on a 6-point Likert scale, with higher scores indicating stronger behavioral intention.

Physical activity level was assessed using the International Physical Activity Questionnaire-Short Form (IPAQ-SF), which includes seven items evaluating the frequency and duration of vigorous activity, moderate activity, and walking for at least 10 minutes during the past week. Weekly activity levels (MET-minutes/week) were calculated by multiplying the MET value of each activity category by the reported frequency and duration.

Physical activity compliance was determined based on WHO guidelines. Participants were classified as meeting physical activity recommendations if they achieved at least 150-300 minutes of moderate-intensity aerobic activity per week or 75-150 minutes of vigorous-intensity activity per week, as calculated from the IPAQ-SF. The compliance rate was defined as the proportion of participants who met these criteria.

Delay discounting was assessed using a computerized intertemporal choice task adapted from Figner et al. Participants completed 60 trials in which they chose between a smaller-sooner (SS) reward and a larger-later (LL) reward across varying delays and reward differences. The discounting parameter k was estimated using a hyperbolic discounting model (V = A / (1 + αk)), with higher k values indicating steeper delay discounting.

Consideration of future consequences was measured using the short version of the Consideration of Future Consequences Scale (CFC-S), which includes two subscales: CFC-Future (5 items) and CFC-Immediate (7 items). All items are rated on a 7-point Likert scale, and subscale scores are calculated as the mean of their respective items, with higher scores indicating a stronger tendency to consider future outcomes.

Outcome expectations for exercise were assessed using the Multidimensional Outcome Expectations for Exercise Scale (MOEES), which includes three subscales: physical (6 items), social (4 items), and self-evaluative (5 items). Participants rated each item on a 7-point Likert scale (1 = strongly disagree to 7 = strongly agree) and additionally indicated how soon they expected each outcome to occur using a 7-point temporal expectancy scale (1 = distant future to 7 = immediate). Higher scores reflect more positive and more immediate outcome expectations for exercise.

Subjective cognitive decline was assessed using the 9-item Subjective Cognitive Decline Questionnaire (SCD-9), which evaluates perceived changes in memory and other cognitive domains, including overall memory problems and comparisons with past cognitive functioning. Each item is scored and summed to generate a total score, with higher scores indicating greater subjective cognitive decline. A cutoff score of >5 has been suggested to indicate abnormal subjective cognitive decline in Chinese populations.

Lower-extremity physical function was assessed using the Short Physical Performance Battery (SPPB), which includes three subtests: gait speed, balance tests, and the chair stand test. The SPPB provides a composite score reflecting balance, lower-limb strength, and functional mobility in older adults.

Handgrip strength was measured using a handheld dynamometer. Participants performed two trials with each hand, and the highest value (in kilograms) was recorded as the final grip strength. Higher values indicate better upper-extremity muscle strength.

Calf circumference was measured using a flexible, non-elastic tape at the point of the greatest calf girth while the participant was standing with feet shoulder-width apart. Measurements were recorded in centimeters, with larger values indicating greater lower-limb muscle mass.