Test‐Retest Reliability, Learning Effect and Measurement Error of the Modified Shuttle Test (MST) in Children With Asthma: A Multicenter Study

OBJECTIVE: To investigate test-retest reliability, measurement error (standard error of measurement [SEM] and minimum detectable difference [MDD]), and the learning effect of the Modified Shuttle Test (MST) in children with asthma. METHODS: Multicenter cross-sectional study including clinically stable children aged 6-12 years with asthma. Lung function and exercise capacity were assessed using MST. Intraclass Correlation Coefficient (ICC) was calculated to assess test-retest reliability. The first and second tests were compared using the paired Student's t-test to assess differences between tests. SEM and MDD were calculated to quantify measurement error. RESULTS: One hundred and twenty three children were included (71 boys [57%]; median age 9 [7-10] years). The mean distance covered in the best MST was 611 ± 214 meters (confidence interval [95% CI] = 573-649meters). The MST showed an excellent test-retest reliability (ICC = 0.96; 95% CI: 0.95-0.97). Distance was significantly lower in the second test than in the first (574 ± 218 vs. 601 ± 216 m; p = 0.0001). Learning effect was -27 ± 79 (4% ± 14%), the SEM was 56 meters (9.5%), and the MDD was 156 m (26.6%). CONCLUSION: The MST demonstrated excellent test-retest reliability and acceptable measurement error for assessing exercise capacity in children with asthma. Although a systematic difference was observed between tests, there was no evidence of a consistent learning effect, with individual variability in repeated performance.