Thus, for endurance improvements, an emphasis on the techniques of performance is more beneficial than the programming of assumed physiological stimulations of training. There is no difference between children and non-trained adults relative to physical capacity at the anaerobic threshold. Unlike aerobic capacity, the anaerobic capacity of children expressed per Kg of body weight is much smaller than adults. It is lowest in children and increases progressively with age in both boys and girls. Little to nothing is known about the trainability of anaerobic capacity in children.
Children are endurance animals and are best suited to adapt to aerobic exercises.
Frequent and stressful stimulation of anaerobic metabolism will be particularly fatiguing and if overdone, could be harmful. Children will fatigue rapidly in anaerobic work when compared to their response to endurance work. Since the increase in testosterone production in adolescent children is markedly higher in boys than girls, boys will become stronger faster and to a higher degree. Sophisticated and restrictive weight exercises, particular on machines, are useless for strength-limited children. The rate of development of speed seems to accelerate in two phases.