title: Inspiratory Muscle Strength and Endurance in Children and Adolescents with Cystic Fibrosis.
abstract: BACKGROUND
  Pulmonary changes that occur in cystic fibrosis may influence inspiratory muscle strength and endurance. We evaluated inspiratory muscle strength and endurance in children and adolescents with cystic fibrosis in comparison with healthy subjects.
  
  
  METHODS
  This is a cross-sectional observational study with subjects with cystic fibrosis and paired healthy individuals, age 6-18 y. Spirometry, impulse oscillometry, plethysmography, manovacuometry, and a protocol of inspiratory muscle endurance were performed.
  
  
  RESULTS
  Subjects with cystic fibrosis (n = 34) had higher maximum percent-of-predicted inspiratory pressure (PImax) than healthy (n = 68) subjects (118.5 ± 25.8% vs 105.8 ± 18.0%) and no significant difference in endurance (60.9 ± 13.3% vs 65.3 ± 12.3%). When restricting the analysis to subjects without Pseudomonas aeruginosa colonization and with FEV1 > 80%, PImax values were significantly higher, and inspiratory muscle endurance was lower, in comparison with the control group. PImax correlated significantly with FVC (r = 0.44, P = .02) and FEV1 (r = 0.41, P = .02), whereas endurance correlated better with total airway resistance (r = 0.35, P = .045) and with central airway resistance (r = 0.48, P = .004).
  
  
  CONCLUSIONS
  Children and adolescents with cystic fibrosis with no colonization by P. aeruginosa and normal lung function present increased inspiratory muscle strength and decreased endurance compared with healthy individuals, indicating that changes in the respiratory muscle function seem to be distinctly associated with pulmonary involvement. Strength was related to pulmonary function parameters, whereas endurance was associated with airway resistance.
authors.affiliation: Centro Infant, Institute of Biomedical Research, Pontifícia Universidade Católica do Rio Grande do Sul (PUCRS), Porto Alegre, RS, Brazil.
authors.forename: Fernanda M
authors.initials: FM
authors.lastname: Vendrusculo
authors.affiliation: Centro Infant, Institute of Biomedical Research, Pontifícia Universidade Católica do Rio Grande do Sul (PUCRS), Porto Alegre, RS, Brazil.
authors.forename: João P
authors.initials: JP
authors.lastname: Heinzmann-Filho
authors.affiliation: School of Nursing, Nutrition and Physiotherapy, PUCRS, Porto Alegre, RS, Brazil.
authors.forename: Taila C
authors.initials: TC
authors.lastname: Piva
authors.affiliation: School of Medicine, Universidade Federal do Rio Grande do Sul (UFRGS), Porto Alegre, RS, Brazil.
authors.forename: Paulo J C
authors.initials: PJ
authors.lastname: Marostica
authors.affiliation: Centro Infant, Institute of Biomedical Research, PUCRS, Porto Alegre, RS, Brazil. mdonadio@pucrs.br.
authors.forename: Márcio V F
authors.initials: MV
authors.lastname: Donadio
mesh_terms: D000293:Adolescent; D000403:Airway Resistance / Q000502:physiology; D016022:Case-Control Studies; D002648:Child; D003430:Cross-Sectional Studies; D003550:Cystic Fibrosis / Q000503:physiopathology*; D005260:Female; D005541:Forced Expiratory Volume / Q000502:physiology; D006801:Humans; D007320:Inspiratory Capacity / Q000502:physiology; D008168:Lung / Q000503:physiopathology; D008297:Male; D053580:Muscle Strength; D009991:Oscillometry / Q000379:methods; D010807:Physical Endurance; D010991:Plethysmography / Q000379:methods; D011550:Pseudomonas aeruginosa; D012119:Respiration; D012132:Respiratory Muscles / Q000503:physiopathology*; D013147:Spirometry
keywords: adolescent; child; cystic fibrosis; respiratory muscles