Functional aerobic capacity and body size.

An endurance treadmill exercise test protocol of two minute stages of increasing speed and gradient has been designed and evaluated for children under 10 years of age. There was a significant relation between test protocol time and oxygen uptake measured in ml/kg/min in tests performed on 20 subjects. One hundred and sixty exercise tests performed in a semi longitudinal study of healthy primary schoolchildren were used to assess the relation of functional aerobic capacity with age and size. In boys functional aerobic capacity measured by predicting maximal oxygen uptake from endurance time in the treadmill test increased from 33.8 ml/kg/min at age 5 to 50.5 ml/kg/min at age 9.5 and was most closely related to age. The variables of size were not significant in predicting functional aerobic capacity for boys. In girls functional aerobic capacity increased from 34.9 to 43.5 ml/kg/min at the same ages and was related positively to lean body mass and age but negatively to weight. For girls lean body mass contributed 53.9% to the variance of functional aerobic capacity in stepwise multiple regression, weight 7.7%, and age 3.5%. A significant difference between the sexes was found.