Longitudinal stratification of gait economy in young boys and girls: the locomotion energy and growth study.

The purpose of this study was to determine if the relative ordering of locomotor oxygen consumption ( VO(2)) values remains stable as healthy children age. Beginning at age 6 and ending at age 10, VO(2) during level treadmill walking and running was quantified in 15 boys and 18 girls who were tested on an annual basis. Following 30 min of treadmill accommodation to each exercise mode, subjects walked and ran for 5 min at 1.34 m s(-1) and 2.23 m s(-1), respectively. During the last 2 min of each 5-min stage, expired gas samples were collected and analyzed to quantify VO(2). For both walking (W) and running (R), 27% of subjects showed an average yearly change in VO(2) rank order of

Prediction of the aerobic demand of walking in children.

PURPOSE: The purpose of this study was to develop a generalized equation to predict VO2 during level treadmill walking in young boys and girls. METHODS: On an annual basis from ages 6 to 10, 23 able-bodied children (14 girls, 9 boys) completed six 5-min walking bouts at speeds ranging from 40.2 to 107.2 m x min(-1). Before testing, each child received 60 min of treadmill walking practice. During the last 2 min of each walking trial, a 2-min sample of expired gas was collected in a meteorological balloon and analyzed to determine VO2. RESULTS: Stepwise regression analyses indicated that the following equation was best suited to predict walking VO2: VO2 = 24.852 + 0.003214 (walking speed in m x min(-1))2 - 0.995 (age in yr) - 0.263 (walking speed); R = 0.95; SEE = 1.74 mL x kg(-1) x min(-1). Bland-Altman analysis revealed that 95% of the differences between actual and predicted VO2 values fell within a range of 3.39 to -3.43 mL x kg(-1) x min(-1). CONCLUSION: We conclude that VO2 during level treadmill walking can be predicted accurately in healthy young children.

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< or = 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.