Background/Purpose: Chronic obstructive pulmonary disease (COPD) patients exhibit abnormalities in structure and function of skeletal muscle tissue. It is currently unknown if this leads to breakdown in functional mobility (gait).
Method: Seven COPD patients and three controls walked at a self-selected speed on a treadmill for 3 minutes. The central tendency (standard deviation, coefficient of variation) and regularity (approximate entropy) of step width, length, time, swing time and stance time time-series were calculated and compared to controls using independent t-tests. The COPD patients also walked on the treadmill at +10% and +20% of their self-selected speed with similar data reduction and processing and were compared using dependent t-tests.
Analysis/Results: COPD patients significantly decreased (p=0.017) step width standard deviation and significantly decreased (p<0.001) regularity in step length as compared to controls. The standard deviation of swing time was significantly increased in the slower walking conditions (-20%:p=0.035; -10%:p=0.009) as well as the coefficient of variation at the -10% speed for swing time and step time (p=0.038 & 0.011, respectively). The greatest speed perturbations (-20%:p=0.016; +20%:p=0.004) resulted in significant increases in regularity for step length. Slower walking speeds resulted in significant decreases in regularity for swing time (-20%:p=0.033; -10%:p=0.031).
Conclusions: COPD patients will alter spatiotemporal gait patterns and further, their steps are more irregular as compared to controls. This could be of interest as COPD patients are at higher risk for falls and altered gait variability has been associated with fall risk. COPD patients are sensitive to speed perturbations and potentially could be used in rehabilitation.
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