[Hygienic substantiation of physical load standards in physical education of schoolchildren].

The research specific to the changes in body functioning under the effect of various loads of cyclic character was carried out. The results thus obtained made it possible to analyze sex- and age-specific characteristics of body functional capacities of schoolchildren aged 6-15 (yearly characteristics). It was pointed out that by 13-14 years the schoolchildren, primarily girls, lost some of their adaptation capacity to physical load.