Ventilatory Adaptation to Concentric Versus Eccentric Exercise in Patients With Severe COPD (CONvEX)

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.

Dynamic hyperinflation will be assessed through iterative inspiratory capacity (IC) measurment during exercise. A decrease in IC >150 mL compared to resting levels at any time point during exercise will be considered as dynamic hyperinflation.

2.4 GHz electromyographic activity of biceps brachii recorded using surface electrod (Cometa Wave Plus wireless EMG)

2.4 GHz electromyographic activity of vastus lateralis recorded using surface electrod (Cometa Wave Plus wireless EMG)

Borg modified scale [ranging from 0 to 10] for dyspnoea 0 indicates no dyspnoea and 10 the maximum dyspnoea

Inclusion Criteria: Severe COPD (FEV1 [forced expiratory volume in 1 second] / FVC [forced vital capacity] < 70% et FEV1 < 50%) Informed consent Affiliation to a social security scheme Exclusion Criteria: Effort oxygen therapy Cardiovascular, neuromuscular or musculoskeletal disorders that can provide significant dyspnea or limit exercise Legal incapacity Low or no cooperation anticipated