Trainability of the cardiorespiratory system during childhood.

Children have long been suspected of having a diminished capability of responding to endurance training with improvements of maximal oxygen uptake compared to adults. However, studies examining the trainability of children have been beset with methodologic flaws that have precluded firm conclusions about such adult/child differences. Most studies in children that have involved adequate intensity, type, and duration of training have demonstrated the same qualitative changes as would be expected from adult subjects. Some information suggests that children may need a greater exercise intensity than adults to trigger cardiovascular adaptations to training. Other data raise questions regarding differences in autonomic influences on the heart and myocardial function in children that could relate to age-dependent responses to training.