Participants in the intervention group will receive training using a self-developed VR-based resistance training system named "Kitten Crossing the Bridge." This system primarily emphasizes static lower-limb resistance control and integrates mechanisms of task rhythm regulation, spatial judgment, and visual feedback. Preliminary usability testing has demonstrated good immersion, safety, and acceptability among older adults.The intervention will last for 4 weeks, with two sessions per week; each session will last approximately 20 minutes (excluding device setup and rest intervals). All sessions will be supervised by trained staff to ensure safety and provide necessary assistance.

Participants in the control group will perform standardized leg-raising exercises. The training rhythm will be guided by pre-recorded verbal prompts and demonstration videos developed by the research team, ensuring that the exercise intensity and pace are aligned with those of the intervention group.

Participants in the intervention group will engage with a self-developed VR resistance training program entitled "Kitten Crossing the Bridge." This program is designed to guide older adults through static lower-limb resistance exercises, while integrating rhythm control, spatial judgment, and visual feedback. The intervention will be administered over 4 weeks, with two sessions per week; each session will last approximately 20 minutes (excluding equipment setup and rest periods). All training sessions will be supervised by qualified staff to ensure participant safety and provide necessary support.

Neural activity during the intervention tasks will be recorded using a functional near-infrared spectroscopy (fNIRS) imaging system. A 24-channel NirLight fNIRS device (Huairui Medical Technology Co., Ltd., China) will be employed, with light sources operating at wavelengths of 760-850 nm and a sampling rate of 10 Hz. The probe configuration will primarily cover the frontal, parietal, and parts of the temporal and occipital lobes.

The Chinese version of the Addenbrooke's Cognitive Examination Ⅲ (ACE-Ⅲ) is a validated neuropsychological instrument designed to assess objective cognitive function across five domains: attention, memory, verbal fluency, language, and visuospatial ability. The total score ranges from 0 to 100, with higher scores indicating better cognitive function.

The Beijing version of Montreal Cognitive Assessment (MoCA) is a classical screening tool for mild cognitive impairment that evaluates seven cognitive domains: visuospatial and executive function, naming, attention, language, abstraction, delayed recall, and orientation. The total score ranges from 0 to 30, with higher scores indicating better cognitive performance.

The Subjective Cognitive Decline Questionnaire (SCD-Q9) is a brief 9-item self-report questionnaire used to assess subjective cognitive symptoms in older adults. The total score ranges from 0 to 9, with higher scores reflecting more severe subjective cognitive decline.