Severe COPD Alters Muscle Fiber Conduction Velocity During Knee Extensors Fatiguing Contraction

Gennaro Boccia, Giuseppe Coratella, Davide Dardanello, Nicoletta Rinaldo, Massimo Lanza, Federico Schena, Alberto Rainoldi

Research output: Contribution to journalArticlepeer-review


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.

Original languageEnglish
Pages (from-to)1-6
Number of pages6
JournalCOPD: Journal of Chronic Obstructive Pulmonary Disease
Publication statusAccepted/In press - Feb 24 2016


  • Electromyography
  • isometric contraction
  • neuromuscular fatigue
  • power spectral frequency
  • vastus lateralis
  • vastus medialis

ASJC Scopus subject areas

  • Pulmonary and Respiratory Medicine


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