Effects of Resistance-based Exercise Snacks With Varying Fragmentation Patterns on Lower Limb Function and Executive Cognition in Pre-frail Older Adults

Condition(s) studied

Investigational drug(s) / intervention(s)

Highly Fragmented Exercise Snack: Participants in Arm 1 perform a resistance-based exercise snack consisting of three exercises: sit-to-stand, squat, and heel raise. Each bout contains 1 repetition of each exercise (1-1-1 structure). Participants complete 15 bouts per day, with each bout taking approximately 30 seconds. The total daily volume is 15 repetitions per exercise (45 total repetitions). The intervention period is 8 weeks. Participants are instructed to use event-based triggers (e.g., after each bathroom visit or after drinking water) to initiate each bout. A demonstration video and a daily exercise log are provided.

Moderately Fragmented Exercise Snack: Participants in Arm 2 perform a resistance-based exercise snack consisting of three exercises: sit-to-stand, squat, and heel raise. Each bout contains 3 repetitions of each exercise (3-3-3 structure). Participants complete 5 bouts per day, with each bout taking approximately 90 seconds. The total daily volume is 15 repetitions per exercise (45 total repetitions). The intervention period is 8 weeks. Participants are instructed to perform bouts at fixed time points (e.g., morning, mid-morning, noon, afternoon, evening). A demonstration video and a daily exercise log are provided.

Lowly Fragmented Exercise Snack: Participants in Arm 3 perform a resistance-based exercise snack consisting of three exercises: sit-to-stand, squat, and heel raise. Each bout contains 5 repetitions of each exercise (5-5-5 structure). Participants complete 3 bouts per day, with each bout taking approximately 2.5 minutes. The total daily volume is 15 repetitions per exercise (45 total repetitions). The intervention period is 8 weeks. Participants are instructed to perform bouts at three fixed time points (e.g., morning, noon, evening). A demonstration video and a daily exercise log are provided.

Consecutive Exercise (Active Control): Participants in Arm 4 perform a resistance-based exercise session consisting of three exercises: sit-to-stand, squat, and heel raise. Each bout contains 15 repetitions of each exercise (15-15-15 structure). Participants complete 1 bout per day, with the bout taking approximately 7.5 minutes. The total daily volume is 15 repetitions per exercise (45 total repetitions). The intervention period is 8 weeks. Participants are instructed to perform the bout at a fixed time each day (e.g., 10:00 AM). A demonstration video and a daily exercise log are provided.

Study summary

This four-arm randomized pilot trial (N=48-60) compares four fragmentation patterns of a three-exercise resistance snack (sit-to-stand, squat, heel raise; 15 repetitions/exercise/day) in pre-frail older adults (Fried score 1-2, ≥70 years). Groups differ by repetitions/bout×bouts/day: G1=1×15, G2=3×5, G3=5×3, G4=15×1. Outcomes (lower limb strength, balance, executive function) are assessed at baseline, week 4, and week 8. The study will determine the optimal fragmentation pattern and provide effect sizes for a future definitive trial.

Eligibility

Primary outcome measure(s)

• Lower Limb Muscle Strength — Baseline (Week 0), Mid-intervention (Week 4), Post-intervention (Week 8)
  Measured by the 30-Second Chair Stand Test (30-CST). The number of times a participant can stand up from a sitting position and sit back down within 30 seconds. A higher score indicates better lower limb strength.
• Dynamic Balance and Mobility — Baseline (Week 0), Mid-intervention (Week 4), Post-intervention (Week 8)
  Measured by the Timed Up and Go (TUG) test. The time (in seconds) taken to stand up from a chair, walk 3 meters, turn around, walk back, and sit down. A shorter time indicates better dynamic balance and mobility.

Trial sites (1)

More Capital University of Physical Education and Sports, China trials in China