Resistance-Based Multicomponent Training Plus Nutrition Supplementation for Intrinsic Capacity and Disability Risk in Chinese Rural Older Adults

This study aims to determine whether resistance-dominant multicomponent training combined with leucine-enriched whey protein and vitamin D supplementation can improve intrinsic capacity and reduce disability risk in rural Chinese older adults. The study focuses on the locomotion and vitality domains of intrinsic capacity, which are closely related to mobility function, nutritional status, muscle reserves, and the ability to maintain independent daily living.

Eligible participants will be rural community-dwelling adults aged 60 years or older who present at least one of the following risk characteristics: reduced physical performance, low gait speed, nutritional risk, sarcopenia risk, or pre-frailty/frailty. After baseline assessment, participants will be randomly allocated in a 1:1:1:1:1 ratio to one of five study groups: control group, nutrition supplementation group, resistance training group, resistance training plus nutrition supplementation group, and resistance-dominant multicomponent training plus nutrition supplementation group.

The traditional resistance training program will include progressive functional resistance exercises such as chair sit-to-stand, chair-assisted squat, calf raise, elastic-band knee extension, elastic-band hip abduction, elastic-band rowing, wall push-up, and shoulder press. The resistance-dominant multicomponent training program will use resistance training as the core component and will additionally include balance, gait, aerobic, flexibility, and breathing relaxation exercises. Exercise sessions will be conducted three times per week for 12 weeks.

The nutritional supplementation will consist of approximately 20 g/day whey protein, 2.5-3.0 g/day total leucine, and 800-1000 IU/day vitamin D3. The supplement will be administered twice daily. On training days, one dose will be taken within 30 minutes to 2 hours after exercise, and another dose after breakfast. On non-training days, the supplement will be taken after breakfast and dinner.

Outcome assessments will be performed at baseline and at week 12. The primary outcomes are the Short Physical Performance Battery score, FRAIL score, and activities of daily living/instrumental activities of daily living scores. Secondary outcomes include 4-meter gait speed, Timed Up and Go test, five-times sit-to-stand test, 30-second chair stand test, handgrip strength, Mini Nutritional Assessment Short Form score, daily protein intake, serum 25-hydroxyvitamin D, body mass index, calf circumference, appendicular skeletal muscle mass index, and quality of life. Safety outcomes include renal function, blood calcium, falls, musculoskeletal injury, gastrointestinal symptoms, and other adverse events.

• Routine Health Education (Behavioral): Participants will receive routine health education during the 12-week study period. The health education will include general advice on healthy aging, physical activity safety, balanced diet, fall prevention, and chronic disease self-management. Participants will not receive structured exercise training or active nutritional supplementation as part of this intervention.
• Isocaloric Placebo (Dietary supplement): Participants will receive an isocaloric placebo that is similar to the active nutritional supplement in appearance, taste, packaging, and administration frequency. The placebo will be administered during the 12-week study period.
• Leucine-Enriched Whey Protein and Vitamin D Supplementation (Dietary supplement): Participants will receive a nutritional supplement containing approximately 20 g/day whey protein, 2.5 to 3.0 g/day total leucine, and 800 to 1000 IU/day vitamin D3. The supplement will be administered twice daily for 12 weeks. On training days, one dose will be taken within 30 minutes to 2 hours after exercise, and the other dose will be taken after breakfast. On non-training days, the supplement will be taken after breakfast and dinner.
• Progressive Resistance Training (Behavioral): Participants will complete supervised progressive resistance training three times per week for 12 weeks, with each session lasting 45 to 60 minutes. Exercises will include chair sit-to-stand, chair-assisted squat, calf raise, elastic-band knee extension, elastic-band hip abduction, elastic-band rowing, wall push-up, and shoulder press. Training intensity will progress from RPE 3-4/10 during weeks 1-4, to RPE 5-6/10 during weeks 5-8, and RPE 6-7/10 during weeks 9-12.
• Resistance-Dominant Multicomponent Training (Behavioral): Participants will complete supervised resistance-dominant multicomponent training three times per week for 12 weeks, with each session lasting 50 to 65 minutes. The program will use resistance training as the core component and will also include balance, gait, aerobic, flexibility, and breathing relaxation exercises. Each session will include approximately 25 to 30 minutes of resistance training, 8 to 10 minutes of balance and gait training, 8 to 10 minutes of aerobic exercise, and 5 minutes of stretching and relaxation.

Primary outcomes

• Change From Baseline in Short Physical Performance Battery Score at Week 12 [Baseline and Week 12]: The Short Physical Performance Battery will be used to assess lower-extremity physical performance, including standing balance, 4-meter gait speed, and five-times sit-to-stand performance. Total scores range from 0 to 12, with higher scores indicating better physical performance.
• Change From Baseline in FRAIL Score at Week 12 [Baseline and Week 12]: The FRAIL scale will be used to assess frailty status. The scale includes fatigue, resistance, ambulation, illness, and loss of weight. Scores range from 0 to 5, with higher scores indicating greater frailty risk.
• Change From Baseline in Activities of Daily Living Score at Week 12 [Baseline and Week 12]: Activities of daily living will be assessed to evaluate basic self-care ability in daily life. Higher scores indicate better basic daily living function.
• Change From Baseline in Instrumental Activities of Daily Living Score at Week 12 [Baseline and Week 12]: Instrumental activities of daily living will be assessed to evaluate more complex daily living abilities. Higher scores indicate better instrumental daily living function.

Sex: All, ages: 60 Years to any

Inclusion Criteria:

1. Aged 60 years or older.
2. Rural residents who have lived in the study area for at least 6 months and have no plan for long-term absence during the study period.
3. Able to walk independently or with a cane for a short distance.
4. Meeting at least one of the following risk characteristics: Short Physical Performance Battery score of 9 or lower, usual gait speed of 0.8 m/s or lower, Mini Nutritional Assessment Short Form score of 11 or lower, SARC-F score of 4 or higher, possible sarcopenia according to the Asian Working Group for Sarcopenia 2019 criteria, or FRAIL score of 1 to 3.
5. Able to understand the study requirements and provide written informed consent.

Exclusion Criteria:

1. Unstable cardiovascular or cerebrovascular events within the past 6 months.
2. Severe uncontrolled hypertension, defined as resting systolic blood pressure of 180 mmHg or higher or diastolic blood pressure of 110 mmHg or higher.
3. Severe cognitive impairment that prevents understanding of or cooperation with the study procedures.
4. Severe osteoarticular disease or neurological disease affecting exercise safety.
5. Severe renal dysfunction, such as estimated glomerular filtration rate lower than 30 mL/min/1.73 m², or considered unsuitable for protein supplementation by the study physician.
6. Hypercalcemia, active kidney stones, or contraindications to vitamin D supplementation.
7. Allergy to whey protein or any component of the nutritional supplement.
8. Regular use of protein powder, beta-hydroxy-beta-methylbutyrate, creatine, or other nutritional supplements that may affect muscle metabolism within the past 3 months.
9. Participation in another interventional study.

• yongzhao f, PhD, Principal investigator, Henan Normal University