Chronic obstructive pulmonary disease (COPD) is a major respiratory illness that is both preventable and treatable. Dyspnea is the most important symptom that COPD patients experience and this can have a major impact on their daily live. While COPD is characterized by a spectrum of disease severity, most patients experience poor exercise intolerance attributable to ventilatory limitation as well as peripheral muscle fatigue, ultimately leading to severe disability.
Endurance exercise is an important component of pulmonary rehabilitation and is aimed at preventing this decline in functional capacity. The effects of pulmonary rehabilitation are largely attributable to the exercise training component involving concentric muscle contractions, traditionally trough dynamic, large muscle exercise on a cycle ergometer or treadmill. However, many patients are unable to partake and benefit from such rehabilitation because of locomotor muscle weakness and severe ventilatory limitation that prevent them from exercising at intensities sufficient to provoke improvements in cardioventilatory and skeletal muscle function. Eccentric exercise is known for its unique physiologically fundamental characteristics: the lower metabolic demand for a same power output and greater muscle gains compared to the concentric exercise. For this reason, eccentric endurance training has been proposed as a novel adjunctive rehabilitative countermeasure for certain chronic diseases (such as coronary disease and COPD) and can play an important role for patients with advanced disease.
