Departments of Women's and Children's Health and Public Health and Caring Sciences, Uppsala University, (S-75185) Uppsala, Sweden. Department of Public Health and Caring Sciences, Uppsala University, (S-75185) Uppsala, Sweden. Departments of Women's and Children's Health and Public Health and Caring Sciences, Uppsala University, (S-75185) Uppsala, Sweden. Department of Women's and Children's Health, Uppsala University, (S-75185) Uppsala, Sweden.
Aim: 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, age 5 - 16 years participated 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 rate. 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. Conclusion: 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 evaluation of gait efficiency in children.