title: Electrophysiologic changes during exercise testing in patients with chronic obstructive pulmonary disease.
abstract: To determine whether skeletal muscle is involved in the exercise limitation of chronic obstructive pulmonary disease (COPD), we investigated electrical adaptations in muscle during incremental cycling exercise testing. Changes in quadriceps activity were compared using surface electromyography (SEMG) and motor point stimulation in ten COPD patients and ten healthy subjects. Patients showed significantly lower exercise capacity, and M-wave duration was increased from exercise onset (P < 0.05) with a parallel decrease in amplitude (P < 0.05). The SEMG power spectrum median frequency was always higher (P < 0.04) in patients and its decline was earlier (P < 0.01). The ratio of the root mean square of the SEMG to oxygen uptake was decreased (P < 0.001) during exercise in patients, although it remained constant in controls. Electromyographic parameters were significantly more involved in the exercise limitation than ventilatory factors. Thus, modified electrical activity in muscle appeared in COPD patients from exercise onset, indicating that skeletal muscle function is clearly implicated in the exercise intolerance of these patients.
authors.affiliation: Laboratoire de Physiologie des Interactions, Hôpital Arnaud de Villeneuve, 371 avenue du Doyen G. Giraud, 34295 Montpellier, France. nadege.gosselin@staps.univ-montp1.fr
authors.forename: Nadège
authors.initials: N
authors.lastname: Gosselin
authors.forename: Stéphane
authors.initials: S
authors.lastname: Matecki
authors.forename: Magali
authors.initials: M
authors.lastname: Poulain
authors.forename: Michèle
authors.initials: M
authors.lastname: Ramonatxo
authors.forename: François
authors.initials: F
authors.lastname: Ceugniet
authors.forename: Christian
authors.initials: C
authors.lastname: Préfaut
authors.forename: Alain
authors.initials: A
authors.lastname: Varray
mesh_terms: D000138:Acidosis / Q000503:physiopathology; D000368:Aged; D004576:Electromyography; D005080:Exercise Test; D006801:Humans; D008875:Middle Aged; D018656:Muscle Fibers, Fast-Twitch / Q000502:physiology; D018482:Muscle, Skeletal / Q000166:cytology / Q000503:physiopathology*; D010101:Oxygen Consumption; D005082:Physical Exertion; D029424:Pulmonary Disease, Chronic Obstructive / Q000175:diagnosis* / Q000503:physiopathology*; D012146:Rest