Patients with chronic obstructive pulmonary disease walk with altered step time and step width variability as compared with healthy control subjects

Jennifer M. Yentes, Stephen I. Rennard, Kendra K. Schmid, Daniel Blanke, Nicholas Stergiou

Research output: Contribution to journalArticlepeer-review

22 Scopus citations


Rationale: Compared with control subjects, patients with chronic obstructive pulmonary disease (COPD) have an increased incidence of falls and demonstrate balance deficits and alterations in mediolateral trunk acceleration while walking. Measures of gait variability have been implicated as indicators of fall risk, fear of falling, and future falls. Objectives: To investigate whether alterations in gait variability are found in patientswithCOPDas comparedwith healthy control subjects. Methods: Twenty patients withCOPD(16 males; mean age, 63.6± 9.7 yr; FEV1/FVC, 0.52±0.12) and 20 control subjects (9 males; mean age, 62.568.2 yr) walked for 3minutes on a treadmill while their gait was recorded. The amount (SD and coefficient of variation) and structure of variability (sample entropy, a measure of regularity) were quantified for step length, time, and width at three walking speeds (selfselected and 620% of self-selected speed). Generalized linear mixed models were used to compare dependent variables. Results: Patients withCOPDdemonstrated increased mean and SD step time across all speed conditions as compared with control subjects. They also walked with a narrower step width that increased with increasing speed, whereas the healthy control subjects walked with a wider step width that decreased as speed increased. Further, patients with COPD demonstrated less variability in step width, with decreased SD, compared with control subjects at all three speed conditions. No differences in regularity of gait patterns were found between groups. Conclusions: Patients with COPD walk with increased duration of time between steps, and this timing is more variable than that of control subjects.They also walk with a narrower stepwidth inwhich the variability of the step widths from step to step is decreased. Changes in these parameters have been related to increased risk of falling in aging research. This provides a mechanism that could explain the increased prevalence of falls in patients with COPD.

Original languageEnglish (US)
Pages (from-to)858-866
Number of pages9
JournalAnnals of the American Thoracic Society
Issue number6
StatePublished - Jun 2017


  • Biomechanics
  • Entropy
  • Gait
  • Locomotion
  • Lung disease

ASJC Scopus subject areas

  • Pulmonary and Respiratory Medicine


Dive into the research topics of 'Patients with chronic obstructive pulmonary disease walk with altered step time and step width variability as compared with healthy control subjects'. Together they form a unique fingerprint.

Cite this