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This Article Full Text (PDF) All Versions of this Article: chest.07-2823v1 133/5/1155    most recent Submit a response Alert me when this article is cited Alert me when eLetters are posted Alert me if a correction is posted Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Add to My Personal Article Archive Download to citation manager Citing Articles Citing Articles via Google Scholar Google Scholar Articles by Bansal, V. Articles by Goldstein, R. S Search for Related Content PubMed PubMed Citation Articles by Bansal, V. Articles by Goldstein, R. S

Modifying track layout from straight to circular has a modest effect on the six-minute walk distance

¹Department of Respiratory Medicine, West Park Healthcare Centre, Toronto, Ontario ²Department of Physical Therapy, University of Toronto, Toronto, Ontario ³Respiratory Diagnostic & Evaluation Services and ⁴Physical Therapy Department, West Park Healthcare Centre, Toronto, Ontario ⁵Department of Medicine, University of Toronto, Toronto, Ontario, Canada

rgoldstein{at}westpark.org

Abstract

Background: The protocol used for the six-minute walk test influences its results. The only study to examine the effect of modifying track layout performed a retrospective analysis and concluded that institutions using continuous tracks yield greater distances than those using straight tracks. Agreement between the distances measured on different tracks could not be examined. We evaluated the effect of modifying track layout on walk distance and examined the agreement and repeatability of distances measured on different tracks.

Methods: In a prospective, randomized, cross-over study, 27 COPD subjects (FEV₁=38±14%; 15 males) attended 3 separate test sessions, completing 6 six-minute walk tests. To familiarize all subjects with both tracks, the first two sessions comprised two six-minute walk tests on either a circular or straight track. During the final session, each subject was tested once on the straight and once on the circular track.

Results: The distance walked on the circular track exceeded the straight track by 13±17 m (p<0.001). The limit of agreement between tracks was 33 m. The coefficient of repeatability when the test was completed on different days for the straight and circular tracks was 51 and 65 m, respectively.

Conclusions: When evaluating changes in 6MWD in groups of patients, track layout should be standardized. However, the effect of modifying track layout on an individual's walking distance is small compared to their daily variability in walk distance. Therefore standardizing track layout for any given individual may be inconsequential when evaluating the change in distances from tests performed on different days.

Key Words: chronic obstructive pulmonary disease • exercise test • rehabilitation