Diagnostic Value of the Five Times Sit-to-Stand Test and Other Functional Measures in Patients with Arteriosclerosis Obliterans

<b>Background/Objectives:</b> Physical examination techniques are commonly used for the diagnosis and evaluation of Arteriosclerosis Obliterans (ASO). However, these methods do not objectively reflect the degree of claudication or functional impairment reported by patients. Moreover, standardized functional metrics to facilitate consistent clinical communication and prognostic assessments among healthcare providers are lacking. This study aimed to identify performance-based functional tests that enable quantitative assessment of symptoms and gait limitation in patients with ASO and to propose them as objective, reproducible clinical indicators. <b>Methods:</b> Fifty-six participants (27 patients with ASO and 29 healthy controls) underwent multiple functional tests, including the Five Times Sit-to-Stand Test (FTSS), six-minute walk test (SMWT), gait speed, Short Physical Performance Battery (SPPB), and grip strength. Test results were compared between the groups and evaluated against ankle-brachial index (ABI) values for diagnostic and functional relevance. <b>Results:</b> Patients with ASO demonstrated significantly lower SPPB scores, slower gait speed, longer FTSS times, and shorter SMWT distances than controls, whereas grip strength did not differ. Random forest and receiver operating characteristic analyses identified the FTSS, SMWT, and gait speed as significant predictors of ASO. <b>Conclusions:</b> The FTSS, SMWT, and gait speed are simple and clinically meaningful performance-based measures that can complement the ABI in the evaluation of ASO. Combining the FTSS with the SMWT and gait speed may provide a more comprehensive and reliable functional assessment and facilitate early screening, guide clinical decision-making, and enable objective evaluation of functional recovery before and after treatment, while improving patient self-assessment and communication among healthcare providers.