Identification of Explanatory Factors for the Lack of Muscle Strength Gain Following a Pulmonary Rehabilitation Program in COPD Patients

Chronic Obstructive Pulmonary Disease (COPD) is a chronic respiratory disease associated with various comorbidities, including muscle weakness (MW), which is very worrying due to its negative impact on patients' quality of life and survival. To address this issue, muscle strengthening is incorporated into pulmonary rehabilitation programs. However, its effectiveness is unclear, as although there is an average improvement in muscle strength, one in two patients does not show a clinically relevant improvement. To understand this non-response, it is crucial to examine the effect of muscle strengthening programs on the two main determinants of force production: the muscle and the central command. Muscle adaptations following a muscle strengthening program are well-documented, showing improvements in muscle function (cross-sectional area, lean mass, etc.). Conversely, only one study has investigated central adaptations after a muscle strengthening program, clearly demonstrating a lack of effect. The investigators hypothesize that patients showing no improvement in muscle strength after pulmonary rehabilitation (non-responders) have a significantly lower level of voluntary activation before starting the program compared to responding patients (responders).