The influence of a set of exercises on the development of endurance of secondary school students is revealed in the article. One of the factors that adversely affects the health of school-age children is the low mobility of life. Therefore, physical education occupies a special place in the system of physical education of school-age children. Physical fitness testing is an element of stage control both in the sports training system and in the practice of physical education. However, the ability of children of different ages to exercise some physical activity is limited by the adaptive potential of the growing organism's systems, and as practice shows, the reserve capacity of the student body is significantly reduced, which negatively affects the physical qualities of children, and especially endurance. Endurance is considered one of the basic motor abilities of the person. The endurance index with great precision indicates the overall health of the person and the functionality of the respiratory and cardiovascular systems. Analyzing the indicators of the level of endurance development in the studied contingent of children it is established that the level of endurance development of students of 4-5 grades, is equal to the mark of 3 points, which corresponds to the "average level". The study shows changes in the level of endurance development in students engaged in the recommended complexes and the relationship of endurance types with indicators of overall physical performance. The results of the correlation analysis showed the presence of a high correlation of static endurance with dynamic endurance (r = 0,883). Also, a high statistical relationship is observed in the study of the relationship of dynamic strength endurance and speed-endurance (r = 0,858). Preparing a physically healthy and in all respects advanced generation is an important task of our society. Properly organized physical education and sports, which should be included in the daily life of young people from an early age, occupy the first place in this task.