Endocrine Abstracts

Physical activity is any body movement produced by the skeletal muscle and that results in a substantial increase over the resting energy expenditure (REE). Training is physical activity and systematic, specialized practice for a specific sport discipline. This activity may have an effect on growth and biological maturation of young athletes. For males the more successful age group athletes are on-time or advanced in biological maturation, but the opposite is true (on-time or behind) for girls, especially in the aesthetic sports such as rhythmic gymnastics. The gymnasts are often at a large daily energy deficit.

Bone mineral accrual is an important component of biological maturation and is most plastic before and during early puberty than at virtually any other time in life. The reproductive system is particularly vulnerable to energy deficits and to a greater extent in gynecologically younger adolescents. I shall close with an example in the male to show the metabolic consequences of a high energy output at lower energy intake in the weight-class related sport of wrestling.