title: Severe COPD Alters Muscle Fiber Conduction Velocity During Knee Extensors Fatiguing Contraction.
abstract: The aim of this study was to assess the changes in muscle fiber conduction velocity (CV), as a sign of fatigue during knee extensor contraction in patients with chronic obstructive pulmonary disease (COPD) as compared with healthy controls. Eleven male patients (5 with severe and 6 with moderate COPD; age 67 ± 5 years) and 11 age-matched healthy male controls (age 65 ± 4 years) volunteered for the study. CV was obtained by multichannel surface electromyography (EMG) from the vastus lateralis (VL) and medialis (VM) of the quadriceps muscle during isometric, 30-second duration knee extension at 70% of maximal voluntary contraction. The decline in CV in both the VL and VM was steeper in the severe COPD patients than in healthy controls (for VL: severe COPD vs. controls -0.45 ± 0.07%/s; p < 0.001, and for VM: severe COPD vs. controls -0.54 ± 0.09%/s, p < 0.001). No difference in CV decline was found between the moderate COPD patients and the healthy controls. These findings suggest that severe COPD may impair muscle functions, leading to greater muscular fatigue, as expressed by CV changes. The results may be due to a greater involvement of anaerobic metabolism and a shift towards fatigable type II fibers in the muscle composition of the severe COPD patients.
authors.affiliation: a Motor Science Research Center, School of Exercise & Sport Sciences, SUISM, Department of Medical Sciences, University of Turin , Torino , Italy.|b CeRiSM Research Center, Sport, Mountain, and Health , Rovereto , ( TN ), Italy.
authors.forename: Gennaro
authors.initials: G
authors.lastname: Boccia
authors.affiliation: c School of Sport and Exercise Sciences, Department of Neurological and Movement Sciences, University of Verona , Verona , Italy.
authors.forename: Giuseppe
authors.initials: G
authors.lastname: Coratella
authors.affiliation: a Motor Science Research Center, School of Exercise & Sport Sciences, SUISM, Department of Medical Sciences, University of Turin , Torino , Italy.
authors.forename: Davide
authors.initials: D
authors.lastname: Dardanello
authors.affiliation: c School of Sport and Exercise Sciences, Department of Neurological and Movement Sciences, University of Verona , Verona , Italy.
authors.forename: Nicoletta
authors.initials: N
authors.lastname: Rinaldo
authors.affiliation: c School of Sport and Exercise Sciences, Department of Neurological and Movement Sciences, University of Verona , Verona , Italy.
authors.forename: Massimo
authors.initials: M
authors.lastname: Lanza
authors.affiliation: b CeRiSM Research Center, Sport, Mountain, and Health , Rovereto , ( TN ), Italy.|c School of Sport and Exercise Sciences, Department of Neurological and Movement Sciences, University of Verona , Verona , Italy.
authors.forename: Federico
authors.initials: F
authors.lastname: Schena
authors.affiliation: a Motor Science Research Center, School of Exercise & Sport Sciences, SUISM, Department of Medical Sciences, University of Turin , Torino , Italy.
authors.forename: Alberto
authors.initials: A
authors.lastname: Rainoldi
mesh_terms: D000368:Aged; D016022:Case-Control Studies; D004576:Electromyography; D005541:Forced Expiratory Volume; D006801:Humans; D007537:Isometric Contraction; D008297:Male; D008875:Middle Aged; D018763:Muscle Fatigue; D018485:Muscle Fibers, Skeletal / Q000502:physiology*; D005082:Physical Exertion / Q000502:physiology; D029424:Pulmonary Disease, Chronic Obstructive / Q000503:physiopathology*; D052097:Quadriceps Muscle / Q000503:physiopathology*; D012720:Severity of Illness Index
keywords: Electromyography; isometric contraction; neuromuscular fatigue; power spectral frequency; vastus lateralis; vastus medialis