Objective. The muscle strength (MS) of the hands is used to assess the level of physical fitness in children and adolescents in restorative, sports medicine, physiotherapy exercises. However, the dependence of MS on the physical development of children and adolescents has not been adequately studied, taking into account the population variability of these indicators. Methods. Using the standard anthropometric method, the physical development of 308 boys, 11 to 17 years old, was studied in the dynamics of education in a general education institution. There were three groups sorted by the rate of maturation: the retardant boys (the biological age is less than the calendar age), the medians (the biological age corresponds to the calendar year), and the accelerants (the biological age is ahead of the calendar one). Strength index (SI) and adolescence mass index were calculated Results. With the increase in the calendar age from 11 to 17 years of age, MS increases from 15.1±0.3 to 37.5±0.7 kg, SI - from 38.1±0.7 to 55.1 ±1.2 units. The age dynamics of the SI varied depending on the rates of biological maturation of boys. MS increased in the prepubertal and early pubertal periods. There was a different age-related dynamics of Ms in adolescent boys, taking into account "tallness". According to the SI, boys with an elevated body mass index were significantly inferior to the other two groups in all age groups. Conclusions. There are sensitive (critical) periods in the formation of MS in adolescent boys associated with periods of maximum growth rate. Differences are observed in boys with different rates of biological maturation, so "retardants" are inferior to boys with biological development outstripping and corresponding age. The formation of MS is affected by both deficits and excess body weight. From the indicators of physical development in the formation of MS in adolescents contributes to the length of the body, as well as the rate of biological maturation, which is indicated by the length of the body. A negative contribution to the formation of MS is made by the body weight.