The State of the Cardiovascular System of Qualified Table Tennis Athletes at the Stage of Competitive Activity
Authors:   Ivano-Frankivsk, Ivano-Frankivsk National Technical University of Oil and Gas. apt. 54, 7a, Fedkovich St., Ivano-Frankivsk 76008, Ukraine, V. M. Ulizko , Kryzhanivsky V. R. , Zakharkevich T. M. , Belyavsky I. L. 
Published: September 2021

The condition of the cardiovascular system is one of the important criteria for assessing the impact of sports training on the human body. According to the indicators characterizing the state of the cardiovascular system, it is possible to trace the changes associated with fluctuations in the level of training, as well as to identify signs of overload as early as possible. The study of adaptive reactions of the cardiovascular system in athletes under physical activity is an important indicator for sports practice. The purpose of the study was to investigate the quantitative criteria for assessing the state of the cardiovascular system and approaches to correct the functional state of qualified athletes specializing in table tennis. Materials and methods. Studies of heart rate variability, quantitative and qualitative indicators that sufficiently reflect the autonomic functions of the body were used in order to assess the state of autonomic regulation in highly qualified athletes. Systematic physical activity causes a significant restructuring of the cardiovascular system and leads to morphofunctional changes in the mechanisms of the heart. Depending on the autonomic regulation of heart rhythm, there are different ways of myocardial adaptation processes. The balance of sympathetic and parasympathetic links of autonomic rhythm regulation is reflected in the activation of the left ventricle. Results and discussion. Adaptive changes of the cardiovascular system to competitive and training loads in the competitive period in qualified athletes are characterized by a significant decrease in heart rate (from 84.75±1.74 beats / min to 74.8±0.38 beats / min). In addition, a significantly faster process of restoring heart rate was established after exercise in the group of qualified athletes, compared with athletes of the category 1 at 4 (p >0.05) and 5 (p >0.05) minutes, respectively. According to the indicators of autonomic regulation of heart rhythm, activation of the parasympathetic link prevails in athletes of the category 1 in comparison with qualified athletes activation (according to high-frequency component, p <0.05). Significantly higher rates of individual parts of the body compared to low-skilled athletes were found out: the hormonal system (the indicator responsible for the hormonal part of the body – very low-frequency component) and the nervous system (indicators of the sympathetic nervous system – low frequency component). There are significantly higher values of the magnitude of the heart rate spectrum and high-frequency component at p <0.05, which indicates a higher power of all units of the parasympathetic regulation in the category 1 in relation to masters of sports and candidates masters of sports. Conclusion. Systematic physical activity causes a significant restructuring of the cardiovascular system and leads to morphofunctional changes in the mechanisms of the heart. Depending on the autonomic regulation of heart rhythm, there are different ways of myocardial adaptation processes. The balance of sympathetic and parasympathetic links of autonomic rhythm regulation is reflected in the activation of the left ventricle. The analysis showed that the spectral characteristics of heart rate variability significantly differ between groups of athletes with different dominance that are observed only in terms of high-frequency component, which in turn led to a change in the sympathetic-vagal balance