Health of children and adolescents is an essential criterion of well-being of the society. Monitoring of health among children is impossible without assessment of physical development of children and adolescents. Individual-based analysis of anthropometric characteristics is required to develop personalized preventive activities. Considering different levels of physical load of schoolchildren in case of a disturbed nutritional status, an approach to body mass constituent study that deviates from the normal values requires examination. The study purpose was to assess physical development and component composition in schoolchildren during a medical examination and in children involved in classic swimming at a sports club in the city of Samara. The study object involved children studying at a general educational institution and not engaged in any sports sections (first group), and children involved in classic swimming at a sports club in Samara (second group. Significant differences in basic values of body composition were found during the conducted study of physical development and component composition of schoolchildren who do not go in for sports and junior athletes.