Six-minute walk test in adults with cerebral palsy. A study of reliability

Objective: To determine the reliability of a six-minute walk test in adults with cerebral palsy. Design: Four repeated walk tests during two weeks. Setting: The tests were conducted in a 40-m-long corridor at a rehabilitation centre for outpatients. Subjects: Twenty-five adults (9 women and 16 men) with CP. Mean age 36 (26-58) years. Twelve subjects walked with walking aids and 13 without. Interventions: No intervention. Measures: The subjects were instructed to walk as far as possible for 6 min. The distance walked, heart rate and perceived exertion were assessed. Results: Mean distances walked by the subjects in the four tests were 316, 336, 341 and 345 m. The repeatability between test 1 and the other tests was 66 m, and when the first walk test was excluded 40 m. The coefficient of variation (CV) between test 1 and the other tests varied between 7.1 and 8.7%, and when the first walk test was excluded between 3.7 and 4.5%. Intraclass correlation (ICC 1.1) was 0.97 in the four tests, and when the first walk test was excluded 0.99. Walking distance was longer (P < 0.01) and varied less in subjects walking without walking aids (n = 13) compared with subjects using walking aids (n = 12). Conclusions: Six-minute walk test showed high reliability, with a repeatability of 40 m. One practice test is recommended, as the walking distance in the first test was significantly shorter (P < 0.01) than the other three tests.