title: Muscular Dysfunction in COPD: Systemic Effect or Deconditioning?
abstract: BACKGROUND
  Muscular dysfunction has been described as one of the systemic manifestations of chronic obstructive pulmonary disease (COPD).
  
  
  OBJECTIVE
  The aim of this study was to evaluate muscular strength of the different anatomical compartments in patients with severe COPD compared with healthy controls.
  
  
  METHODS
  We performed a cross-sectional study in patients with severe COPD. We evaluated the muscular strength of the respiratory muscles, flexors and extensors of the cervical spine and knee, as well as handgrip force. The 6-min walking test (6MWT) and serum inflammatory markers were also analysed.
  
  
  RESULTS
  Twenty-eight male patients with COPD (mean age 67.8 years, mean FEV1 (%) 39 %) and 24 male healthy controls (mean age 70.2 years) were studied. The strength of the flexors and extensors of the knee was significantly reduced in patients with COPD (p < 0.001 and p = 0.003). No differences were observed in the flexors and extensors of the cervical spine and handgrip force between groups. No correlation was observed between the muscular strength in the different anatomic compartments and the concentrations of blood inflammatory biomarkers or the metres walked in the 6MWT in COPD patients. However, a significant negative linear correlation was observed between the 6MWT and IL-6 and IL-8 levels (rho = -0.67, p = 0.001; rho = -0.57, p = 0.008). In addition, we found a negative correlation between the 6MWT and inspiratory capacity (rho = -0.755, p = 0.031).
  
  
  CONCLUSIONS
  Our results suggest that muscular dysfunction in patients with COPD differs in different muscular compartments. The main factor for a reduced exercise capacity was a reduction in inspiratory capacity.
authors.affiliation: Physical Medicine and Rehabilitation Department, Hospital Mataró, C/Cirera s/n 08302, Mataró, Barcelona, Spain. epleguezuelos@csdm.cat.|Department of Experimental Science and Healthcare, Faculty of Health Sciences, Universitat Pompeu Fabra, Barcelona, Spain. epleguezuelos@csdm.cat.|Faculty of Health Sciences Blanquerna, Universitat Ramón LLull, Barcelona, Spain. epleguezuelos@csdm.cat.
authors.forename: Eulogio
authors.initials: E
authors.lastname: Pleguezuelos
authors.affiliation: Pneumology Department, Hospital Universitari Vall d'Hebron, Ciber de Enfermedades Respiratorias (CIBERES), Barcelona, Spain.
authors.forename: Cristina
authors.initials: C
authors.lastname: Esquinas
authors.affiliation: Physical Medicine and Rehabilitation Department, Hospitalet General Hospital, L´Hospitalet de Llobregat, Barcelona, Spain.
authors.forename: Eva
authors.initials: E
authors.lastname: Moreno
authors.affiliation: Physical Medicine and Rehabilitation Department, Hospital Mataró, C/Cirera s/n 08302, Mataró, Barcelona, Spain.
authors.forename: Lluis
authors.initials: L
authors.lastname: Guirao
authors.affiliation: Biomechanics Laboratory, INVALCOR, Barcelona, Spain.
authors.forename: Javier
authors.initials: J
authors.lastname: Ortiz
authors.affiliation: Biomechanics Laboratory, INVALCOR, Barcelona, Spain.
authors.forename: Joan
authors.initials: J
authors.lastname: Garcia-Alsina
authors.affiliation: Department of Experimental Science and Healthcare, Faculty of Health Sciences, Universitat Pompeu Fabra, Barcelona, Spain.|Faculty of Health Sciences Blanquerna, Universitat Ramón LLull, Barcelona, Spain.
authors.forename: Alex
authors.initials: A
authors.lastname: Merí
authors.affiliation: Pneumology Department, Hospital Universitari Vall d'Hebron, Ciber de Enfermedades Respiratorias (CIBERES), Barcelona, Spain.
authors.forename: Marc
authors.initials: M
authors.lastname: Miravitlles
mesh_terms: D000368:Aged; D015415:Biomarkers / Q000097:blood; D016022:Case-Control Studies; D003430:Cross-Sectional Studies; D005080:Exercise Test; D017079:Exercise Tolerance; D005541:Forced Expiratory Volume; D018737:Hand Strength; D006801:Humans; D018836:Inflammation Mediators / Q000097:blood; D001239:Inhalation; D007537:Isometric Contraction; D008168:Lung / Q000503:physiopathology*; D008297:Male; D008875:Middle Aged; D053580:Muscle Strength; D018482:Muscle, Skeletal / Q000503:physiopathology*; D029424:Pulmonary Disease, Chronic Obstructive / Q000097:blood / Q000150:complications / Q000175:diagnosis / Q000503:physiopathology*; D012720:Severity of Illness Index
chemical_list: D015415:Biomarkers; D018836:Inflammation Mediators
keywords: COPD; Deconditioning; Inflammatory markers; Muscle function