Motor ability and sport performance in children training

As shown in the figure below, the motor ability of boys and girls generally increases with age for the first 17 years, although girls tend to plateau at about the age of puberty for most items tested. These improvements result primarily from development of the neuromuscular and endocrine systems and secondarily from the increased activity.

The plateau observed in the girls at puberty is likely explained by three factors. First, as mentioned earlier, the increase in estrogen levels at puberty, or in the estrogen/testosterone ratio, leads to increased fat deposition. Performance tends to decrease as fat increases. Second, girls have less muscle mass. Finally, and probably of greater importance, around puberty many girls assume a much more sedentary lifestyle than boys. This is largely a matter of social conditioning, as boys are encouraged to be more active and athletic than girls. As girls become less active, their motor abilities tend to plateau. This trend appears to be changing because of changing social attitudes and more opportunities for sport and activity now available for girls.

Sport performance in children and adolescents improves with growth and maturation, as can be seen for age-group records in sports such as swimming and track and field. Figure below illustrates the improvement in American records for various age-groups.

The figure gives values for the 100m and 400m swim and the 100m and 1,500m run. These events were selected because they represent a predominantly anaerobic event in swimming and running(100m swim and run) and a predominantly aerobic activity(400m swim and 1,500m run). Both anaerobic and aerobic performance improve progressively with increasing age-groups, with the exception of the 1,500m run for 17-and 18-year-old girls. Similar age-group records for weightlifting do not appear to be available, because weightlifting competition is organized by weight in broad classifications such as 16 and under, 17 to 20 years of age, and then adult classifications. On the basis of normal strength gains with growth and development, it is assumed that weightlifting records would increase markedly from late childhood through adolescence, particularly in boys.