Assessing functional capacity in patients with chronic low back pain: validity and reliability of the Glittre-ADL test

Background While chronic low back pain (CLBP) impairs individuals’ capacity to perform activities of daily living (ADL), objective, performance-based assessments of functional capacity in this patient population remain limited.Purpose This study aimed to investigate the test–retest reliability and construct validity of the Glittre-ADL test as an assessment tool for ADL and functional capacity in individuals with CLBP.Methods This cross-sectional study involved 42 participants (28 female, 14 male), with a median age of 42.50 years (Q1–Q3: 24.50–54.25). The Glittre-ADL test was used to evaluate ADL performance. Construct validity was examined by correlating Glittre-ADL performance with comparator measures assessing related domains, including functional exercise capacity using the 6-minute walk test (6MWT), lower extremity endurance using the 1-minute sit-to-stand test (1STS), functional mobility using the timed up and go (TUG) test, and self-reported disability using the Oswestry Disability Index (ODI). Test–retest reliability was evaluated by repeating the Glittre-ADL test after a one-week interval. The intraclass correlation coefficient [ICC(A,1)], standard error of measurement (SEM), and minimal detectable change at the 95% confidence level (MDC95) were subsequently calculated.Results The ICC(A,1) for repeated Glittre-ADL measurements was 0.776 (95% CI: 0.389–0.903), with an SEM of 0.40 min and an MDC95 of 1.12 min. Strong correlations were observed between the first Glittre-ADL test result and 6MWT distance (r = −0.789, p < .001) and TUG time (r = 0.797, p < .001). Moderate correlations were observed with 1STS repetitions (r = −0.531, p < .001) and ODI score (r = 0.542, p < .001), supporting its construct validity.Conclusion As an objective, performance-based measure, the Glittre-ADL test demonstrated evidence of test–retest reliability and construct validity for assessing ADL-related functional limitations in individuals with CLBP. However, completion time was systematically shorter at the second assessment, suggesting a possible learning or familiarization effect; therefore, changes observed across repeated Glittre-ADL assessments should be interpreted cautiously.