Studied the expression and change in functional parameters of the same girls and boys of different somatotypes between 8 and 10 years. In ascertaining experiment was attended by 80 girls and boys who at baseline was 8 years old. Found that girls and boys the same age but different somatotypes. They are similar trends: a high level of features to ensure aerobic metabolic reactions, higher aerobic and anaerobic capacity lower, below the required functionality to most of the studied systems. The features associated primarily with the age in which the possibility of a deteriorating system. The above must be considered when choosing the optimal parameters of physical activity and develop programs to improve the functionality of primary school children during physical education.