Evaluation of Safety and Efficacy of a Digital Therapeutic Device to Improve Strength in Sarcopenia (Sarc-DTx)

Inclusion Criteria * Individuals diagnosed with sarcopenia according to both the European Working Group on Sarcopenia in Older People (EWGSOP) criteria and the Asian Working Group for Sarcopenia 2019 (AWGS 2019) criteria * Individuals with reduced muscle strength, defined as at least one of the following: * Handgrip strength \< 28 kg for men or \< 18 kg for women * Five-times Sit-to-Stand Test time \> 12 seconds without arm support * Individuals with reduced muscle mass, defined as at least one of the following: * Skeletal Muscle Mass Index (SMI) \< 7.0 kg/m² for men or \< 5.4 kg/m² for women measured by DXA * Skeletal Muscle Mass Index (SMI) \< 7.0 kg/m² for men or \< 5.7 kg/m² for women measured by BIA * Individuals able to independently perform sit-to-stand movements * Individuals with sufficient physical and cognitive capacity to participate in the exercise program * Individuals able and willing to provide written informed consent * Individuals able to operate a mobile phone independently or with assistance from a caregiver Exclusion Criteria * Individuals with cognitive impairment, defined as a Mini-Mental State Examination (MMSE) score \< 20, or those unable to participate due to cognitive decline * Individuals with an implanted cardiac pacemaker or other implanted electronic medical device * Individuals with uncontrolled cardiovascular disease despite appropriate medical management * Individuals who have undergone lower-limb surgery within the past 6 months and are unable to ambulate independently * Individuals with moderate-to-severe musculoskeletal pain or functional limitations that interfere with objective functional assessments * Individuals with severe obesity, defined as a body mass index (BMI) \> 50 kg/m² * Individuals currently receiving active cancer treatment or experiencing severe systemic frailty * Individuals with hemiplegia that prevents participation in the prescribed exercise program * Individuals who are anticipated by the investigator to be unable to complete the study procedures or follow-up assessments * Individuals unable to understand or comply with study instructions provided in Korean * Individuals considered unsuitable for study participation at the discretion of the investigator for any other reason