title: Cardiopulmonary fitness and muscle strength in patients with osteogenesis imperfecta type I.
abstract: OBJECTIVE
  To evaluate cardiopulmonary function, muscle strength, and cardiopulmonary fitness (VO 2 peak) in patients with osteogenesis imperfecta (OI).
  
  
  METHODS
  In 17 patients with OI type I (mean age 13.3 +/- 3.9 years) cardiopulmonary function was assessed at rest using spirometry, plethysmography, electrocardiography, and echocardiography. Exercise capacity was measured using a maximal exercise test on a bicycle ergometer and an expired gas analysis system. Muscle strength in shoulder abductors, hip flexors, ankle dorsal flexor, and grip strength were measured. All results were compared with reference values.
  
  
  RESULTS
  Cardiopulmonary function at rest was within normal ranges, but when it was compared with normal height for age and sex, vital capacities were reduced. Mean absolute and relative VO 2 peak were respectively -1.17 (+/- 0.67) and -1.41 (+/- 1.52) standard deviations lower compared with reference values ( P < .01). Muscle strength also was significantly reduced in patients with OI, ranging from -1.24 +/- 1.40 to -2.88 +/- 2.67 standard deviations lower compared with reference values.
  
  
  CONCLUSIONS
  In patients with OI type I, no pulmonary or cardiac abnormalities at rest were found. The exercise tolerance and muscle strength were significantly reduced in patients with OI, which might account for their increased levels of fatigue during activities of daily living.
authors.affiliation: Department of Pediatric Physical Therapy & Exercise Physiology, Wilhelmina Children's Hospital, University Medical Center Utrecht, The Netherlands. t.takken@wkz.azu.nl
authors.forename: Tim
authors.initials: T
authors.lastname: Takken
authors.forename: Heike C
authors.initials: HC
authors.lastname: Terlingen
authors.forename: Paul J M
authors.initials: PJ
authors.lastname: Helders
authors.forename: Hans
authors.initials: H
authors.lastname: Pruijs
authors.forename: Cornelis K
authors.initials: CK
authors.lastname: Van der Ent
authors.forename: Raoul H H
authors.initials: RH
authors.lastname: Engelbert
mesh_terms: D000293:Adolescent; D000328:Adult; D002648:Child; D004562:Electrocardiography; D005080:Exercise Test; D005260:Female; D018737:Hand Strength; D006339:Heart Rate; D006801:Humans; D008168:Lung / Q000503:physiopathology*; D008297:Male; D009132:Muscles / Q000503:physiopathology*; D010013:Osteogenesis Imperfecta / Q000145:classification / Q000503:physiopathology*; D010101:Oxygen Consumption; D010808:Physical Examination; D010993:Plethysmography, Whole Body; D012016:Reference Values; D012720:Severity of Illness Index; D013147:Spirometry; D014797:Vital Capacity