Pulmonary rehabilitation (PR) based on concentric exercise training has become an integral component in the treatment of patients with chronic obstructive pulmonary disease (COPD), improving functional capacities while diminishing symptoms and improving quality of life.~However, the response to concentric exercise training is heterogeneous from one COPD patient to another. The inability of some COPD patients to achieve the exercise intensities required to stress limb muscles due to severe ventilatory limitation could partially explain their poor response to training.~Endurance exercise with eccentric muscle contractions could be an interesting alternative to concentric exercise because it produces greater muscle force through its lower metabolic cost. Eccentric exercise could allow patients with severe airflow limitation to perform prolonged exercise sessions with sufficient intensity to improve muscle function.~Nevertheless, a recent study performed in healthy young subjects reported that eccentric exercise induced a more hyperpneic breathing pattern (i.e., lower tidal volume and higher breathing frequency) that concentric for a given minute ventilation.~The main objective of CONvEX study is to compare ventilatory adaptation between two modalities of exercise performed on cycle ergometer (concentric versus eccentric) in severe COPD patients.
Pulmonary rehabilitation (PR) based on concentric exercise training has become an integral component in the treatment of patients with chronic obstructive pulmonary disease (COPD), improving functional capacities while diminishing symptoms and improving quality of life.~However, the response to concentric exercise training is heterogeneous from one COPD patient to another. The inability of some COPD patients to achieve the exercise intensities required to stress limb muscles due to severe ventilatory limitation could partially explain their poor response to training.~Endurance exercise with eccentric muscle contractions could be an interesting alternative to concentric exercise because it produces greater muscle force through its lower metabolic cost. Eccentric exercise could allow patients with severe airflow limitation to perform prolonged exercise sessions with sufficient intensity to improve muscle function.~Nevertheless, a recent study performed in healthy young subjects reported that eccentric exercise induced a more hyperpneic breathing pattern (i.e., lower tidal volume and higher breathing frequency) that concentric for a given minute ventilation.~The main objective of CONvEX study is to compare ventilatory adaptation between two modalities of exercise performed on cycle ergometer (concentric versus eccentric) in severe COPD patients.