The reliability and validity of the 30-second chair sit-to-stand test and the five-repetition sit-to-stand test in individuals following lumbar spinal surgery.

Abstract

This study investigated the reliability and validity of the five-repetition sit-to-stand (5xSTS) and 30-second chair sit-to-stand (30s-CST) tests in individuals after lumbar spinal surgery. This prospective psychometric study included individuals who had undergone lumbar spinal surgery and were at least 6 weeks post-operatively. Participants performed the 30s-CST, 5xSTS, 10-meter walk test (10MWT), and timed up and go test (TUG), with 2-minute rest intervals between tests. One hour later, the 30s-CST and 5xSTS were repeated for retest analysis. Test-retest reliability and agreement were assessed using the intraclass correlation coefficient (ICC) and Bland-Altman analysis, respectively. ICC values were interpreted as follows: >0.90 excellent, 0.75-0.90 good, 0.50-0.75 moderate, and < 0.50 poor. Concurrent validity was evaluated using Pearson correlation coefficients, and standard error of measurement (SEM) and minimal detectable change (MDC95) were also calculated. A total of 128 individuals were assessed for eligibility; 18 were excluded, and 110 participants were included in the final analysis. The test-retest reliability was excellent for both the 30s-CST [ICC (2,1) = 0.958, 95% CI: 0.939-0.971] and the 5xSTS [ICC (2,1) = 0.946, 95% CI: 0.922-0.962]. The SEM and MDC95 values were 0.56 and 1.55 for the 30s-CST, and 0.52 and 1.44 for the 5xSTS, respectively. Bland-Altman analysis revealed good agreement between test and retest measurements for both tests, with narrow limits of agreement and minimal systematic bias. Furthermore, both the 30s-CST and 5xSTS exhibited strong concurrent validity, demonstrating significant correlations with functional mobility measures, including the 10MWT and TUG. The 30s-CST and 5xSTS are suggested to be reliable and valid performance tests for individuals after lumbar spinal surgery.