Individual phenotypes of physiological adaptation in adolescent football players under submaximal physical load

The purpose of the study is to investigate the adaptive potential of 12–13-year-old young football players based on an analysis of autonomic reactivity patterns during a submaximal stress test. Research methods and organization. The study involved 17 professionally training young men. The following research methods were used: analysis of scientific and methodological literature, testing, and mathematical-statistical methods for processing experimental data. A submaximal stress test (shuttle run and push-ups) was used, and heart rate variability indicators were assessed before and after the load. Research results and conclusions. The load exposure revealed significant interindividual differences in physiological reactivity, enabling the identification of two adaptive phenotypes: one characterized by satisfactory adaptation and another by unsatisfactory adaptation. The findings reflect varying levels of training status and adaptive capacity among the athletes. The analysis of autonomic reactivity is advisable to apply for the individualization and adjustment of training loads in order to increase their effectiveness and prevent adaptation breakdown in adolescent football players.