[Sports and physical training in childhood--general principles]

Whether functional performance of children in response to exercise adapts in a similar way to that of adults and exactly what the influence of growth and maturation is in determining a child's performance has not been completely resolved. Regarding to respiratory factors the younger the child the higher the pulmonary ventilation per liter of oxygen consumption. Girls tend to have a higher ventilatory volume in exercise than boys and after puberty it is significantly lower in boys than in girls. Maximal oxygen consumption increases with age in both sexes as a consequence of increased size but aerobic capacity in children is more related to size and body composition than age. Regarding to cardiovascular factors aerobic capacity is largely determined by maximum cardiac output which itself is dependent upon stroke volume and rate of heart beat, because young children have smaller hearts, they have higher heart rates to compensate for the smaller stroke volume compared with adults. Children have higher maximum heart rates than adults, ranging from approximately 195-220 beats/minute. After maturity there is a decrease in heart rate with age of approximately 0.8 beats/min/year of age. Because of the larger hearts greater stroke volumes and an increased blood volume after puberty males have a higher resting systolic blood pressure than females.(ABSTRACT TRUNCATED AT 250 WORDS)