The paper is devoted to the issues of improving the methods of physical training. Currently, the method of teaching and training schoolchildren is developed mainly with a focus on a child's age, which does not always correspond to his or her biological maturity. These reasons together with the growing phenomenon of child acceleration reinforce the relevance of the research topic. The purpose of the study is to evaluate the impact of speed-strength exercises on the physical development and speed-strength qualities of schoolchildren aged 11-12. The authors used the measurements of anthropometric and physiometric indicators, as well as the tests that determine the level of development of speed and speed-strength qualities. The results of the research show that the physical indicators of the test group tend to increase, and during the school year, many indicators significantly change.