Peripheral artery disease (PAD) is a chronic and progressive condition caused by narrowing or blockage of arteries in the lower limbs due to atherosclerosis. It primarily affects adults over 50, with prevalence increasing with age, and its clinical presentation ranges from asymptomatic cases to severe ischemia that may require amputation. Intermittent claudication, characterized by exercise-induced leg pain that resolves with rest, is the most common early symptom. Impaired blood flow, poor vascularization, and muscle loss contribute to reduced lower limb strength and functional capacity, which are associated with higher morbidity and mortality.

Walking exercises is a cornerstone of PAD management, particularly for patients with no or mild symptoms, making the assessment of lower limb strength and mobility essential for designing rehabilitation programs. The 30-second sit-to-stand test is a validated and practical measure of functional capacity and walking ability. Tele-assessment using video technology has been shown to be feasible and reliable in other patient populations. Although tele-rehabilitation has been widely studied and shown to improve functional outcomes, research on tele-assessment methods to accurately evaluate patient performance and the effectiveness of rehabilitation programs is still limited, particularly in PAD patients.

This study aims to examine the reliability of the 30-second sit-to-stand test when performed via tele-assessment compared with face-to-face evaluation in patients with PAD.

Peripheral artery disease (PAD) is a progressive, chronic cardiovascular disorder characterized by narrowing and occlusion of the lower extremity arteries due to atherosclerosis. Peripheral artery disease (PAD) predominantly affects individuals over the age of 50, with its prevalence increasing progressively with age. The clinical presentation of PAD varies widely, from asymptomatic cases to severe ischemia that may necessitate amputation. Globally, PAD affects over 200 million individuals, while in Turkey, prevalence has been reported at 19.76%. Major risk factors include age, race, sex, smoking, diabetes, hypertension, dyslipidemia, and sedentary lifestyle.

Peripheral artery disease (PAD) commonly presents with intermittent claudication (IC), characterized by exercise-induced lower limb pain that resolves with rest. IC, resulting from reduced oxygen delivery to leg muscles due to arterial obstruction, manifests as pain, cramps, or numbness during activity and may progress to rest pain in advanced stages, affecting 10-35% of patients. Impaired circulation, decreased vascularization, and muscle atrophy contribute to reductions in lower extremity strength and functional capacity, which are associated with increased morbidity and mortality. The Fontaine classification system stages PAD severity from asymptomatic (Stage I) to critical limb ischemia with ulceration or gangrene (Stage IV).

Management strategies include lifestyle modification, exercise, pharmacological therapy, and surgical interventions, with exercise recognized as the most effective and cost-efficient approach for asymptomatic or mildly symptomatic patients. Assessing lower limb strength and mobility is essential for tailoring rehabilitation programs, as PAD patients show significant deficits in functional mobility and muscle strength compared to healthy individuals. The 30-second sit-to-stand test is a validated, practical measure of lower extremity function and is an independent predictor of walking capacity in PAD.

Tele-assessment methods, enabled by internet and smartphone technologies, offer remote evaluation of functional mobility using tests such as the 30-second sit-to-stand, timed up-and-go, and five-repetition sit-to-stand tests. Evidence suggests tele-assessment is reliable, feasible, and cost- and time-efficient, particularly for elderly or mobility-limited populations. However, its accuracy depends on technology quality and patient compliance. Despite studies in populations with type 2 diabetes, hip osteoarthritis, and cancer, the reliability and agreement of the 30-second sit-to-stand test via tele-assessment have not yet been evaluated in PAD patients. Investigating this could inform the development of tele-rehabilitation programs targeting lower extremity strength and functional mobility in PAD.

Therefore, this study aims to investigate the reliability of the 30-second sit-to-stand test between tele-assessment and face-to-face assessment in patients with peripheral artery disease (PAD).

Participants' lower extremity strength and functional mobility will be evaluated using the 30-second sit-to-stand test both face-to-face and online via WhatsApp on the same day. Face-to-face assessments will be conducted at the Department of Cardiovascular Surgery, Dokuz Eylül University Faculty of Medicine.

During tele-assessment, the physiotherapist and the patient will be at the Department of Cardiovascular Surgery; however, the physiotherapist will be in a separate room and will complete the evaluation synchronously via online video. Face-to-face and tele-assessments will be performed by two different physiotherapists participating in the study. The two assessments will be conducted 20-30 minutes apart, and to control for any potential test order effect, the sequence of assessments will be randomized for each participant and physiotherapist using a simple random number table.

During the face-to-face assessment, demographic and clinical information will be collected, including age, sex, body weight and height, body mass index, educational level, occupation, marital status, lifestyle habits (smoking, alcohol consumption, physical activity), medical history (past illnesses), and clinical data (year of PAD diagnosis, disease duration, medications, and comorbidities).

Inclusion Criteria:

• Aged between 18 and 65 years
• Diagnosed with peripheral artery disease, Fontaine stage I-II, confirmed by peripheral angiography or Doppler ultrasonography
• Willingness to participate in the study
• Access to a smartphone and the internet

Exclusion Criteria:

• Presence of orthopedic, neurological, or psychological conditions that limit physical activity
• Neurological or musculoskeletal disorders affecting standing or walking
• History of ischemic amputation
• Acute inflammatory condition
• Use of walking aids
• Visual or hearing impairment
• Vestibular system disorder
• Cognitive impairment affecting cooperation
• Severe cardiopulmonary diseases limiting walking ability
• Major surgery or myocardial infarction within the last three months
• Unstable coronary artery disease

Patients diagnosed with peripheral artery disease, aged 18 to 65 years.

Individual participant data (IPD) will not be shared due to privacy concerns.