Relationships between body dimensions and resting and working oxygen consumption in boys aged 11 to 18 years

Summary

The relationships between $\dot V_{O_2 }$ at rest, $\dot V_{O_{2max} }$ and $\dot V_{O_2 }$ during submaximal work on a treadmill with body weight, height and lean body mass assessed by densitometry were analyzed annually in 39 boys aged 11 to 18 years. Interindividual differences in $\dot V_{O_2 }$ at rest and $\dot V_{O_{2max} }$ during growth depended in the first place on interindividual differences in lean body mass, to a lesser extent on differences in body weight and least on differences in height. Intersubject differences in $\dot V_{O_2 }$ during submaximal work were primarily conditioned by differences in body weight, due to the fact that, at a given running speed, energy output depends on body weight. The differences in submaximal $\dot V_{O_2 }$ depended to a lesser extent on differences in lean body mass and least on differences in height. The relationships between $\dot V_{O_2 }$ increments and increases in body dimensions were somewhat different in 90 boys between the ages of 11 and 15 years: $\dot V_{O_{2max} }$ increments were determined primarily by changes in body weight and height, changes in lean body mass being of secondary importance. Increases in submaximal $\dot V_{O_2 }$ were influenced decisively by increments in body weight, followed by increments in lean body mass and least by increments in height. In the equation y=a·x ^b expressing the relationship of $\dot V_{O_{2max} }$ at the ages of 14 and 15 years were 0.87 and 0.88 in relation to body weight, 2.63 and 2.72 in relation to height. These values are significantly higher than the theoretical values of 0.67 for body weight and 2.00 for height. Similar significant differences from these theoretical values were found for all values between the ages of 11 and 15 years.