The objective of this study was to compare the 6-minute walk distance (6MWD) test performed on a non-motorised treadmill (6MWD-T) with the 6MWD test performed in a corridor (6MWD-C) in healthy elderly subjects. Sixteen healthy elderly individuals. Participants performed three 6MWD-T tests and three 6MWD-C tests on two different days. Distance walked was recorded in metres. Perceived exertion and leg fatigue were rated on the modified Borg scale before and after each test. Using the Bland and Altman limits of agreement analysis method, the mean difference between the two methods was 153.3m (limits of agreement: 28 to 278). The mean difference between days 1 and 2 for the 6MWD-C test was -7.2m (limits of agreement: -45.4 to 30.8), and the mean difference between days 1 and 2 for the 6MWD-T test was -1.6m (limits of agreement: -64.0 to 60.7). The mean difference between the first and second repetitions of the 6MWD-C test was -5m (limits of agreement: -41 to 31), and the mean difference between the first and second repetitions of the 6MWD-T test was -17m (limits of agreement: -85 to 51).
The 6MWD-C and 6MWD-T tests are not interchangeable. However, the results showed good test-retest reliability between days and between test repetitions for both tests. Therefore, the 6MWD-T test may offer an alternative option to the 6MWD-C test when a 30-m corridor is not available. These findings may have implications for execution of the 6MWT-T test within cardiac and pulmonary rehabilitation.
Janaudis-Ferreira T, Sundelin G, Wadell K. Comparison of the 6-minute walk distance test performed on a non-motorised treadmill and in a corridor in healthy elderly subjects. Physiotherapy. 2010 Sep;96(3):234-239