title: Reliability of energy cost calculations in children with cerebral palsy, cystic fibrosis and healthy controls.
abstract: OBJECTIVE
  To study test-retest reliability of physiological cost index (PCI) and total cost index (TCI) in three groups of children. TCI modified PCI by excluding rest heart rate in calculation.
  
  
  METHODS
  Energy cost was evaluated from two consecutive walking tests, and results were compared between methods, tests and groups. Thirty-nine children, eight with cerebral palsy, 11 with cystic fibrosis and 20 healthy controls, aged 5-16 years participated in the study conducted at the Clinical Nutrition and Metabolism laboratory, University Hospital, Uppsala, Sweden. Heart rate was recorded during sitting and walking at self-selected speed. PCI and TCI were calculated using both non-steady-state and steady-state work heart rates. Test-retest reliability was analysed by mean of differences, pooled SD, coefficient of variation (CV%) and correlation coefficients.
  
  
  RESULTS
  Reliability was high for PCI and TCI. TCI showed consistently lower variation between tests than PCI for all groups. In the group with cerebral palsy, using non-steady-state showed highest reliability.
  
  
  CONCLUSIONS
  Both PCI and TCI were reliable methods when calculating energy cost in children with cerebral palsy, cystic fibrosis and controls. TCI seemed to be a suitable alternative in the evaluation of gait efficiency in children.
authors: Department of Public Health and Caring Sciences, Uppsala University, Uppsala, Sweden. linda.bratteby.tollerz@akademiska.se
authors: Linda U
authors: LU
authors: Bratteby Tollerz
authors: Roger M
authors: RM
authors: Olsson
authors: Anders H
authors: AH
authors: Forslund
authors: Simone E
authors: SE
authors: Norrlin
mesh_terms: D000293:Adolescent; D016022:Case-Control Studies; D002547:Cerebral Palsy / Q000503:physiopathology*; D002648:Child; D002675:Child, Preschool; D003550:Cystic Fibrosis / Q000503:physiopathology*; D004734:Energy Metabolism / Q000502:physiology*; D005260:Female; D005684:Gait / Q000502:physiology*; D006801:Humans; D008297:Male; D010101:Oxygen Consumption; D015203:Reproducibility of Results; D013548:Sweden; D016138:Walking / Q000502:physiology*