As part of the study, the physical development of adolescents was evaluated depending on the level of daily motor activity and individual anthropometric indicators of professional athletes. The physical development indicators of 423 boys aged 16 to 18 years were analyzed, which were divided into 3 groups depending on the level of daily physical activity: professional athletes, with additional physical activity, with the usual level of physical activity. The data were collected as a result of a routine medical examination in the period from June to October 2022. The results showed that children aged 16 and 17 with a normal level of motor activity were statistically significantly lower and had less body weight compared to the other groups. The analysis of the fatness index also confirmed the data obtained in the age group of 18‑year-olds. The largest proportion of children (at 16 years — 17.6 %; at 17 years — 33, %) with disharmonious or distinct disharmonious physical development was revealed in the group of children with normal physical activity; no cases of distinct disharmonious level of physical development were found among adolescent athletes. Statistically significant differences in anthropometric indicators among professionally engaged in sports adolescents aged 16 to 18 years were not revealed, while in children with a normal level of physical activity in these age groups, changes in indicators are pronounced, which may indicate an earlier and smoother biological development of adolescent athletes. The use of mass-growth indicators makes it possible to more accurately assess the achieved level of physical development and the level of its harmony.