Findings from a recent study indicate that quadriceps endurance is reduced in individuals with Chronic Obstructive Pulmonary Disease (COPD) in comparison to healthy people, independent of the type of task performed. The results are published in the current issue of Chest, the Official Journal of the American College of Chest Physicians.

Evidence has consistently shown that the aerobic profile of the quadriceps muscle is reduced in patients suffering from COPD, however results are inconsistent on whether this leads to quadriceps muscle endurance. In the study titled “Is Quadriceps Endurance Reduced in COPD?:A Systematic Review,” Evans and colleagues systematically reviewed evidence from published studies that compared quadriceps endurance in healthy individuals and in COPD patients with moderately severe disease. The studies were retrieved from electronic databases and the search involved all studies on the topic published from 1946 to 2011.

A total of 21 studies comprising 728 individuals with a diagnosis of COPD and 440 healthy control subjects met the inclusion criteria. Results revealed that there was a reduction in quadriceps endurance in patients with COPD compared with healthy control subjects. The researchers also found that between patients with COPD and healthy controls, the association did not differ when comparing nonvolitional and volitional techniques or when high- or low-intensity tasks were undertaken.

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“Most of these studies reported a reduced endurance time or a faster decline in contractile force in individuals with COPD compared with healthy control subjects,” Rachel A. Evans, MBChB, PhD from the Department of Respiratory Medicine at the Glenfield Hospital in England said in a recent news release.

Based on the findings, the research team found there is a reduction in quadriceps endurance in patients with COPD independent of the type of task performed. Findings also suggest that patients with COPD should exercise more to improve oxygen uptake.

“The results of this synthesis show that muscle endurance in COPD is reduced, highlighting the need for the inclusion of muscle-specific training, such as one-legged cycling, in improving peak oxygen uptake in COPD,” the researchers said. “Our findings have implications for the development of pharmacologic and nonpharmacologic therapies targeted at improving skeletal muscle endurance.”