title: Quadriceps and ankle dorsiflexor strength in chronic obstructive pulmonary disease.
abstract: BACKGROUND
  Quadriceps strength and size are commonly reduced in chronic obstructive pulmonary disease (COPD). We wished to assess volitional and nonvolitional ankle dorsiflexor strength in COPD.
  
  
  METHODS
  Quadriceps and ankle dorsiflexor strength were measured by maximum voluntary contraction (MVC) and by twitch responses to supramaximal femoral and fibular nerve stimulation. Cross-sectional areas of the tibialis anterior (TA(CSA)) and rectus femoris muscles (RF(CSA)) were measured by ultrasound.
  
  
  RESULTS
  Eighteen elderly subjects and 20 COPD patients [mean(SD) %predictedFEV(1) 50(20)%] participated. No significant difference in fat-free mass index, ankle dorsiflexor strength, or TA(CSA) were observed in the presence of reduced quadriceps strength and size in COPD [mean MVC difference: -10.9 kg (95% confidence interval {CI}: -17.1 kg to -4.8 kg, P < 0.01; mean RF(CSA) difference -119 mm(2), 95% CI: -180 mm(2) to -58 mm(2), P < 0.01)].
  
  
  CONCLUSIONS
  Ankle dorsiflexor strength is less attenuated than quadriceps strength in COPD patients with moderate airflow obstruction. Direct quadriceps assessment may be more relevant than measurement of lower limb fat-free mass.
authors.affiliation: King's College London School of Medicine, London, United Kingdom. john.seymour@fph-tr.nhs.uk
authors.forename: John M
authors.initials: JM
authors.lastname: Seymour
authors.forename: Katie
authors.initials: K
authors.lastname: Ward
authors.forename: Abrar
authors.initials: A
authors.lastname: Raffique
authors.forename: Joerg S
authors.initials: JS
authors.lastname: Steier
authors.forename: Paul S
authors.initials: PS
authors.lastname: Sidhu
authors.forename: Michael I
authors.initials: MI
authors.lastname: Polkey
authors.forename: John
authors.initials: J
authors.lastname: Moxham
authors.forename: Gerrard F
authors.initials: GF
authors.lastname: Rafferty
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D000843:Ankle Joint / Q000502:physiology*; D005080:Exercise Test / Q000379:methods* / Q000592:standards; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D053580:Muscle Strength / Q000502:physiology*; D029424:Pulmonary Disease, Chronic Obstructive / Q000503:physiopathology*; D052097:Quadriceps Muscle / Q000294:innervation / Q000502:physiology*