One-Minute Sit-to-Stand Test Versus Six-Minute-Walk Test in Post-COVID-19 Patients: A Cross-Sectional Observational Study

Background: Simplified field tests have gained increasing interest for the assessment of functional capacity in patients with post-COVID-19 condition; however, direct comparisons of functional performance and physiological responses between the 1-min sit-to-stand test (1MSTST) and the 6-min walk test (6MWT) remain limited. This study aimed to examine the associations between the two tests by evaluating functional performance, cardiopulmonary responses, oxygen desaturation, perceived exertion, and peripheral muscle strength. Furthermore, we explored whether the 1MSTST can be used as a complementary assessment, particularly within telerehabilitation pathways and in contexts where resource-intensive testing is not feasible. Methods: We conducted a cross-sectional observational study of adults recovering from moderate to severe COVID-19 between May and July 2021. Participants performed both the 1MSTST and 6MWT on the same day. Functional performance, peak heart rate, nadir peripheral oxygen saturation (SpO2), perceived exertion, and handgrip dynamometry were recorded. Associations between test performances were assessed using correlation and partial correlation analyses, including adjustment for peripheral muscle strength. Results: Fifty-four patients were included. A moderate correlation was observed between 1MSTST repetitions and 6MWT distance (Spearman’s ρ = 0.47, p < 0.001), which was attenuated after adjustment for muscle strength and demographic variables. Peak heart rate and nadir SpO2 responses were strongly correlated between tests (r = 0.75 and ρ = 0.83, respectively; both p < 0.001), with no significant differences in magnitude. Exercise-induced oxygen desaturation (≥4% SpO2 drop) occurred at similar frequencies during both tests. Perceived exertion increased similarly following the 1MSTST and the 6MWT. Conclusions: In post-COVID-19 patients, the 1 min sit-to-stand test shows moderate concordance with the 6 min walk test for functional performance and strong agreement in cardiopulmonary responses. These findings suggest that the two tests assess overlapping but distinct aspects of functional capacity. This supports the use of the 1MSTST as a pragmatic complementary assessment when standard walking tests are not feasible, particularly within telerehabilitation pathways, primary care, and resource-limited settings.