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.

285 young athlete’s body [6]. During adolescence, when growth, morphofunctional maturation and the formation of regulatory systems are still ongoing, the body’s response to physical load has particular diagnostic significance [3]. It allows one to determine how well the athlete’s body can tolerate loads, recover quickly and form stable adaptation. Among the most informative indicators of the functional readiness of a young futsal player are the state of the blood system, the level of cellular resistance and immunological reactivity [1; 4]. Indicators of the erythrocytic, leukocytic and thrombocytic links of the blood reflect the oxygen-transport capacity of the body, the intensity of metabolic processes, the state of nonspecific defense and the level of homeostatic balance [1; 9]. Their analysis makes it possible to assess not only the current state of the athlete, but also the nature of the adaptive response to training loads. Cellular resistance characterizes the ability of body cells to preserve structural integrity and functional activity under conditions of physical stress, endogenous intoxication and oxidative load [4; 7]. For the selection of promising futsal players, this indicator is of great importance, as it reflects the deep level of the body’s stability under repeated training influences. A high level of cellular resistance may indicate a better ability of the young athlete to tolerate loads without developing excessive functional tension [4]. Immunological reactivity is another important criterion for assessing the adaptive potential of young futsal players [2; 5]. Rationally dosed physical loads contribute to the maintenance of nonspecific resistance, activation of protective mechanisms and formation of a stable immune response [8]. At the same time, excessive or improperly organized loads may lead to immune imbalance, reduced body resistance and an increased risk of illness [2; 3]. Therefore, analysis of immunological indicators allows timely detection of both positive signs of adaptation and possible manifestations of functional overstrain. In this regard, the use of hematological, cellular-resistance and immunological indicators in the system of selection of young futsal players is scientifically justified