Test–retest reliability of the 6-min walk test in patients with postpolio syndrome

Abstract

This study describes the test-retest reliability of the 6-min walk test (6MWT) and evaluates the possibility to perform the test three times on the same day in patients with postpolio syndrome (PPS). This was an intrarater test-retest reliability study. A total of 23 PPS patients (nine men, 14 women), mean age 67 years, participated in the study. The patients performed three 6MWT with a 30-min rest between each test. Borg scales were used to evaluate leg tiredness, dyspnea, and exertion before and after each test. The influence of walking aids on the outcome of the 6MWT was also evaluated. All patients (n=23) were able to complete the three 6MWT. The individual distances varied from 140-395 m. The relative reliability was high. The intraclass correlation coefficient (ICC2.1) (95% confidence interval) values ranged from 0.98 (0.95-0.99) (T1-T2) to 0.99 (0.97-0.99) (T2-T3) for the total number of participants. The SEM ranged from 12 to 9 m and the smallest real difference (SRD) ranged from 33 to 26 m for the total number of participants. Data indicate that the 6MWT is reliable for patients with PPS. For the high test-retest reliability, one test may be required. However, as a small learning effect was observed, the best result of two tests can be recommended when evaluating walking ability for research purposes.