This study will first conduct a precise assessment of the differences in muscle coordination among the elderly through muscle synergy analysis; then, based on this, it will extract abnormal synergy patterns and muscle activation patterns, and reconstruct the intervention's synergy modules to fit the intervention electrostimulation curve; finally, electrical stimulation interventions will be carried out on different elderly individuals under two conditions: sitting and walking, to evaluate the intervention effects and analyze the biomechanical mechanisms of its effectiveness.

The research subjects of this project mainly focus on young people, middle-aged individuals, and elderly individuals who are able to move independently. The investigator's goal is to explore the kinematic and dynamic characteristics of different populations. The main research activities include recruiting young volunteers, middle-aged volunteers, and elderly volunteers who can move independently. Through motion capture, the kinematic data and surface electromyography (sEMG) signal confidence intervals of young and middle-aged subjects are analyzed, and then the kinematic data and sEMG data of independently mobile elderly individuals are examined. The investigator aims to identify multiple muscles that show significant differences compared to normal individuals, and then assess the effectiveness of functional electrical stimulation based on coordinated movement. Additionally, using in vivo motion technology, the investigator will establish a human biomechanics database to analyze the biomechanical characteristics of different populations under various movement conditions.

Inclusion Criteria:

• Must be aged between 65 and 75 years, inclusive.
• Must be community-dwelling.
• Must be able to ambulate independently, with or without the use of an assistive device (e.g., a cane or walker).
• Must be capable of understanding and following study-related instructions and procedures.
• Must provide voluntary written informed consent to participate in the study.

Exclusion Criteria:

• Diagnosis of a significant neurological disorder, including but not limited to stroke, Parkinson's disease, or multiple sclerosis.
• Presence of a severe musculoskeletal condition that would interfere with movement tasks, such as severe osteoarthritis or osteoporosis.
• History of lower limb joint replacement surgery within the last 6 months.
• Cognitive impairment, as indicated by a Mini-Mental State Examination (MMSE) score of less than 24.
• Presence of any implanted electronic medical device, such as a cardiac pacemaker or defibrillator.
• Any skin disease, open wound, infection, or malignancy at the intended sites of electrical stimulation.
• Diagnosis of a severe and/or uncontrolled cardiovascular condition (e.g., unstable angina, recent myocardial infarction).
• Inability to stand independently without support for at least 3 minutes.

This study will employ a single-blind (assessor-blinded) design.

Participants and Therapists: Due to the distinct nature of the two electrical stimulation interventions, blinding of participants and the therapists administering the treatments is not feasible. However, to minimize expectation bias, all participants will be informed that they will be randomized to one of two "effective" types of electrical stimulation therapy, without disclosing the specific differences between them.

Outcome Assessors: All primary and secondary outcome measures will be collected by an independent assessor who is blinded to the group allocation of the participants. This assessor will not be involved in the intervention process and will be strictly instructed to refrain from discussing any treatment-related information with the participants or therapists throughout the study.

Data Analysts: During the data analysis phase, the two groups will be coded as "Group A" and "Group B". The data analyst will per