Proceedings of the International scientific and practical conference ―New York Global Science Conference 2026‖ (May 18-20, 2026) / Publisher website: www.naukainfo.com. – New York, USA, 2026. - 322 p.

289 selection, makes it more objective and allows consideration not only of the external level of preparedness, but also of the internal reserve capacities of the athlete’s body. Conclusions The blood system, cellular resistance and immunological reactivity are important components of the adaptation of young futsal players to systematic physical loads and may be considered informative criteria in the system of selection of promising athletes. Their functional state reflects the level of adaptive reserves of the body, the ability to tolerate training stress and maintain homeostatic balance under conditions of intensive muscular activity. It has been established that the stability of hematological indicators, in particular the erythrocytic, leukocytic and thrombocytic links, indicates a sufficient level of functional readiness of the young athlete and the effectiveness of long-term adaptation mechanisms. Therefore, the assessment of blood system indicators should be used in the selection of promising futsal players as a marker of the body’s resistance to physical loads. An increased level of cellular resistance in trained futsal players characterizes the body’s ability to effectively counteract endogenous intoxication, oxidative stress and microdamage that occur during training activity. This indicates a higher level of functional reserve and may serve as an important criterion for predicting the sports prospects of young athletes. Rationally organized training loads contribute to the formation of a balanced immune response, increased nonspecific resistance and optimization of immunological reactivity without signs of immune overstrain. In this regard, immune system indicators may be used as additional criteria for assessing the adaptive capabilities of young futsal players in the process of sports selection. Thus, the comprehensive consideration of hematological, immunological and cellular-resistance indicators makes it possible to increase the objectivity of selecting promising futsal players, identify athletes with high adaptive potential in a timely manner and optimize the organization of the training process at the stages of long- term sports preparation.