Longitudinal profiles of oxygen uptake during treadmill walking in able-bodied children: the locomotion energy and growth study

The purpose of this study was to document age-related changes in walking V O 2 in able-bodied boys and girls. Beginning at age 6 and ending at age 10, 23 children (14 girls, 9 boys) performed six 5-min bouts of level treadmill walking at 0.67, 0.89, 1.12, 1.34, 1.56, and 1.79 m s −1 on an annual basis. Prior to data collection, subjects received 60 min of treadmill walking practice. During the last 2 min of each walking bout, a 2-min sample of expired air was collected in a meteorological balloon and analyzed to determine V O 2 . Averaged across age, interindividual variation in V O 2 ranged from 32 to 41%. Repeated-measures analysis of variance demonstrated a speed by age interaction for V O 2 , such that mean V O 2 rose ( P≤0.05) across the five fastest speeds for 6-, 7-, 8-, and 10-year olds and increased over the entire speed range for 9-year olds. For all speeds, V O 2 decreased yearly from the ages of 6 to 8. When averaged across speeds, V O 2 was 27% higher for 6-year olds compared with 10-year olds. From a clinical perspective, access to longitudinal measurements of walking V O 2 in able-bodied children should be helpful in interpreting gait energy use in children with movement disorders and evaluating treatment strategies designed to reduce the aerobic demand of locomotion in youth with impaired mobility.