title: Distal leg muscle function in patients with COPD.
abstract: Quadriceps muscle weakness and increased fatigability are well described in patients with chronic obstructive pulmonary disease (COPD). Whether these functional alterations also exist in distal leg muscles in patients with COPD is uncertain. Fifteen patients with COPD and 15 aged-matched healthy controls performed a 12-minute standardized treadmill exercise during which a fixed total expense of 40 Kcal was reached. The strength of i) dorsiflexors, ii) plantar flexors and iii) quadriceps was assessed at rest and after exercise using maximal voluntary contraction (MVC) and potentiated twitch force (Twpot). Resting MVC and Twpot were significantly lower in patients with COPD when compared with controls respectively for i) dorsiflexors (24.9 ± 8.4 vs. 31.2 ± 8.5 Nm, p < 0.05 and 4.3 ± 1.3 vs. 5.7 ± 1.8 Nm, p < 0.05), ii) plantar flexors (49.5 ± 11.8 vs. 62.1 ± 19.6 Nm, p < 0.05 and 10.8 ± 3.5 vs. 13.4 ± 2.7 Nm, p < 0.05), and iii) quadriceps muscles. There was a greater force loss in the distal leg muscles 15 minutes post-exercise in patients with COPD, while the strength of the quadriceps muscle remained stable in both groups. Patients with COPD had weaker dorsiflexor and plantar flexor muscles when compared to age-matched healthy controls. In addition, when exposed to the same absolute walking task, the fatigability of the distal leg muscles was higher in patients with COPD.
authors.affiliation: Centre de recherche, Institut Universitaire de cardiologie et de pneumologie de Québec, Université Laval, Québec, Canada.
authors.forename: Philippe
authors.initials: P
authors.lastname: Gagnon
authors.forename: François
authors.initials: F
authors.lastname: Maltais
authors.forename: Laurent
authors.initials: L
authors.lastname: Bouyer
authors.forename: Fernanda
authors.initials: F
authors.lastname: Ribeiro
authors.forename: Valérie
authors.initials: V
authors.lastname: Coats
authors.forename: Cynthia
authors.initials: C
authors.lastname: Brouillard
authors.forename: Martin
authors.initials: M
authors.lastname: Noël
authors.forename: Mathieu
authors.initials: M
authors.lastname: Rousseau-Gagnon
authors.forename: Didier
authors.initials: D
authors.lastname: Saey
mesh_terms: D000368:Aged; D016022:Case-Control Studies; D005080:Exercise Test; D005260:Female; D006801:Humans; D007866:Leg; D008297:Male; D008875:Middle Aged; D009119:Muscle Contraction; D018763:Muscle Fatigue; D018908:Muscle Weakness / Q000209:etiology*; D018482:Muscle, Skeletal / Q000503:physiopathology*; D010101:Oxygen Consumption; D029424:Pulmonary Disease, Chronic Obstructive / Q000150:complications* / Q000503:physiopathology*; D012123:Pulmonary Ventilation; D052097:Quadriceps Muscle / Q000503:physiopathology; D013990:Tidal Volume