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Comparative Study
. 2012;7(5):e37329.
doi: 10.1371/journal.pone.0037329. Epub 2012 May 18.

Differences in walking pattern during 6-min walk test between patients with COPD and healthy subjects

Janneke Annegarn  1 , Martijn A Spruit, Hans H C M Savelberg, Paul J B Willems, Coby van de Bool, Annemie M W J Schols, Emiel F M Wouters, Kenneth Meijer
Affiliations
Comparative Study

Differences in walking pattern during 6-min walk test between patients with COPD and healthy subjects

Janneke Annegarn et al. PLoS One. 2012.

Abstract

Background: To date, detailed analyses of walking patterns using accelerometers during the 6-min walk test (6MWT) have not been performed in patients with chronic obstructive pulmonary disease (COPD). Therefore, it remains unclear whether and to what extent COPD patients have an altered walking pattern during the 6MWT compared to healthy elderly subjects.

Methodology/principal findings: 79 COPD patients and 24 healthy elderly subjects performed the 6MWT wearing an accelerometer attached to the trunk. The accelerometer features (walking intensity, cadence, and walking variability) and subject characteristics were assessed and compared between groups. Moreover, associations were sought with 6-min walk distance (6MWD) using multiple ordinary least squares (OLS) regression models. COPD patients walked with a significantly lower walking intensity, lower cadence and increased walking variability compared to healthy subjects. Walking intensity and height were the only two significant determinants of 6MWD in healthy subjects, explaining 85% of the variance in 6MWD. In COPD patients also age, cadence, walking variability measures and their interactions were included were significant determinants of 6MWD (total variance in 6MWD explained: 88%).

Conclusions/significance: COPD patients have an altered walking pattern during 6MWT compared to healthy subjects. These differences in walking pattern partially explain the lower 6MWD in patients with COPD.

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Conflict of interest statement

Competing Interests: The authors have declared that no competing interests exist.

Figures

Figure 1
Figure 1. Directions of displacement.
AP: Anterior-posterior direction (forward-backward displacement), V: Vertical direction (up-down displacement), ML: medio-lateral direction (left-right displacement)
Figure 2
Figure 2. Relation between the accelerometer output walking intensity per min and the 6MWD.
A: GOLD stages 1 and 2 with open squares and GOLD stages 3 and 4 with closed circles and B: Healthy subjects
See this image and copyright information in PMC

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