Skeletal muscle dysfunction is common in patients with COPD and has been recognized as a contributing factor to reduced exercise capacity, health related quality of life and increased mortality associated with this disease. Several structural changes in the limb muscles of patients have previously been reported and have been linked to the known reductions in muscle strength and endurance commonly reported in COPD. Muscle dysfunction, lower extremity muscle strength, and muscle fatigue also contribute to the intensity of dyspnea and the ability to sustain exercise mostly through stimulation of type III and IV muscle afferents. As such, many patients who primarily perform aerobic exercise training as part of pulmonary rehabilitation are unable to tolerate the intensity and/or volume of exercise required to achieve clinically important changes in exercise capacity or symptom relief. Resistance training (RT) is an attractive exercise modality for patients with COPD because it is efficacious and often more tolerable initially. To our knowledge no one has examined whether similar benefits to those elicited by longer RT programs can be attained in just 4 weeks using multi-joint, multi-muscle exercises and individualized progression. If a short term RT program can improve muscle quality, enhance endurance, and reduce type III and IV afferent activity then it would reduce the drive to breathe and thus dyspnea. These adaptations would likely translate into improved exercise tolerance making it feasible to "pre-habilitate" COPD patients with tolerable RT, allowing them to achieve a higher volume/intensity of endurance training, thus making pulmonary rehabilitation more effective.
