Is quadriceps endurance reduced in COPD?: a systematic review

Area of Science:

• Pulmonary Medicine
• Exercise Physiology
• Muscle Biology

Background:

• Aerobic capacity of quadriceps muscles is diminished in chronic obstructive pulmonary disease (COPD).
• Conflicting evidence exists regarding the impact of reduced aerobic capacity on quadriceps muscle endurance in COPD patients.

Purpose of the Study:

• To systematically review and analyze studies comparing quadriceps muscle endurance in individuals with COPD versus healthy controls.
• To clarify the relationship between COPD and quadriceps muscle endurance.

Main Methods:

• A systematic review of six electronic databases (1946-2011) was conducted.
• Data from 21 studies (728 COPD patients, 440 controls) were included.
• A random-effects meta-analysis and metaregression were used to synthesize findings and assess measurement influence.

Main Results:

• Quadriceps endurance was significantly reduced in individuals with COPD compared to healthy controls (SMD 1.16, P < .001).
• COPD patients showed a mean reduction of 44.5 seconds in endurance (P = .029), representing a large effect size.
• The difference in endurance between groups was not influenced by the type of measurement technique (volitional vs. nonvolitional) or task intensity.

Conclusions:

• Quadriceps muscle endurance is demonstrably reduced in individuals with COPD.
• This reduction is evident regardless of the specific task or measurement method employed.