The reliability and validity of the timed up and go test in individuals following lumbar spinal surgery.

Abstract

Background: Although the Timed Up and Go (TUG) test is frequently used in lumbar pathologies, its test - retest reliability, convergent validity, and measurement error have not yet been established in the postoperative period.

Objective: The purpose of this study was to comprehensively evaluate the test - retest reliability, convergent validity, andmeasure menterr or of the TUG test in individuals after lumbar spinal surgery.

Methods: A cross-sectional study was conducted with 100 individuals (mean age 55.0 ± 8.9 years; 48 women, 52 men) at least 6 weeks after lumbar spinal surgery. Participants performed the TUG, Five-Repetition Sit-to-Stand Test (5xSTS), and 10-Meter Walk Test (10MWT). The TUG was repeated after a 1-hour rest period. Test - retest reliability was evaluated using the intraclasss correlation coefficient (ICC_2,1). Measurement error was evaluated using the standard error of measurement (SEM), the minimal detectable change at the 95% confidence level (MDC₉₅), and the Bland - Altman limits of agreement (LoA). Convergent validity was assessed using the Pearson correlation coefficient with the 5xSTS and 10MWT.

Results: Excellent test - retest reliability was demonstrated (ICC_2,1 = 0.99; 95% CI: 0.98-0.99). The SEM and MDC₉₅were 0.26 seconds (s) and 0.72 s, respectively. The mean difference (bias) was -0.00 s (95% CI: -0.80 to 0.70), with lower and upper limits of agreement of -0.74 s (95% CI: -0.87 to -0.61) and 0.73 s (95% CI: 0.60 to 0.86), respectively. The TUG showed strong positive correlations with the 5xSTS (r = 0.95, p < .001) and the 10MWT (r = 0.92, p < .001).

Conclusion: The TUG is a reliable and valid tool for measuring functional mobility in individuals after lumbar spinal surgery, providing objective data to complement subjective assessments.