title: Quadriceps weakness contributes to exercise capacity in nonspecific interstitial pneumonia.
abstract: OBJECTIVE
  It has been shown that peripheral muscle dysfunction is a critical factor in determining exercise intolerance in patients with several chronic lung diseases, including idiopathic pulmonary fibrosis. We hypothesized that exercise capacity would be, at least in part, determined by peripheral muscle dysfunction in patients with fibrotic nonspecific interstitial pneumonia (f-NSIP), another major subtype of fibrotic interstitial lung disease. The aim of the current study was to elucidate the relevance of peripheral muscle dysfunction and its contribution to exercise intolerance in f-NSIP.
  
  
  METHODS
  The six-minute walk test was evaluated in 30 consecutive patients with f-NSIP along with potential determinants of exercise capacity, including respiratory muscle force and peripheral muscle force.
  
  
  RESULTS
  Among 30 patients, the median age was 61 years, and 21 were female. Sixteen patients showed significantly decreased quadriceps force (QF), and 17 had significant decreases in maximum expiratory pressure. Exercise capacity and muscle power were clearly related to sex. Adjusted for sex, QF showed a significant relation to exercise capacity measured by six-minute walk distance (6MWD), whereas pulmonary function parameters such as vital capacity showed marginal correlations. In stepwise multiple regression analysis, only QF was an independent predictor of 6MWD.
  
  
  CONCLUSIONS
  Quadriceps weakness is often observed in patients with f-NSIP. It seems that QF significantly contributes to exercise capacity in this population.
authors: Department of Rehabilitation, Tosei General Hospital, Japan.
authors: Fumiko
authors: F
authors: Watanabe
authors: Hiroyuki
authors: H
authors: Taniguchi
authors: Koji
authors: K
authors: Sakamoto
authors: Yasuhiro
authors: Y
authors: Kondoh
authors: Tomoki
authors: T
authors: Kimura
authors: Kensuke
authors: K
authors: Kataoka
authors: Tomoya
authors: T
authors: Ogawa
authors: Shinichi
authors: S
authors: Arizono
authors: Osamu
authors: O
authors: Nishiyama
authors: Yoshinori
authors: Y
authors: Hasegawa
mesh_terms: D000328:Adult; D000368:Aged; D000886:Anthropometry / Q000379:methods; D005080:Exercise Test / Q000379:methods; D017079:Exercise Tolerance / Q000502:physiology*; D005260:Female; D006801:Humans; D054988:Idiopathic Interstitial Pneumonias / Q000150:complications* / Q000503:physiopathology; D008297:Male; D008875:Middle Aged; D018908:Muscle Weakness / Q000209:etiology* / Q000503:physiopathology; D052097:Quadriceps Muscle / Q000503:physiopathology*; D015656:Respiratory Mechanics / Q000502:physiology; D012132:Respiratory Muscles / Q000503:physiopathology; D012189:Retrospective Studies