This study is a five-arm, parallel-group, assessor-blinded randomized controlled trial designed to evaluate the effects of resistance-dominant multicomponent training combined with nutritional supplementation on intrinsic capacity and disability risk among rural Chinese older adults. A total of 220 participants aged 60 years or older with mobility decline, nutritional risk, sarcopenia risk, or pre-frailty/frailty will be randomly assigned to one of five groups: control, nutrition supplementation alone, resistance training alone, resistance training plus nutrition supplementation, or resistance-dominant multicomponent training plus nutrition supplementation. The intervention will last 12 weeks. Exercise interventions will be conducted three times per week, and nutritional supplementation will include leucine-enriched whey protein and vitamin D. 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 gait speed, Timed Up and Go test, sit-to-stand performance, handgrip strength, nutritional status, protein intake, serum 25-hydroxyvitamin D, calf circumference, and appendicular skeletal muscle mass index.