Dr.Hab., Professor A.E. Bolotin¹
Dr.Med., Professor K.-J. van Zwieten²
PhD, Associate Professor O.E. Ponimasov³
Dr. Sc.Philos., Professor N.M. Timchenko⁴
Dr.Hab., Professor S.S. Aganov^4
1St. Petersburg Polytechnic University of Peter the Great, St. Petersburg
²University of Hasselt, Diepenbeek, Belgium
³Russian State Pedagogical University named after A.I. Herzen, St. Petersburg
⁴Saint Petersburg University of the State Fire Service of the Ministry of Emergencies of Russia, St. Petersburg

Objective of the study was to identify differences in the dynamics of the indicators of sympathetic and parasympathetic regulation of heart rate in female swimmers of different fitness levels under the influence of standard training loads.
Methods and structure of the study. Sampled for the study were 2 highly-qualified female swimmers (Swimmer A and Swimmer B) specializing in long-distance swimming, both aged 18 years and trained for the Universiade as part of the Russian Youth National Team. The study was carried out during the autumn-winter semi-cycle. The amount of work in water at the beginning of the mesocycle was 240 km for Swimmer A and 205 km for Swimmer B. During the basic mesocycle, the female athletes performed the same amount and intensity of work. The subjects' cardiographic data were recorded three times a day: twice - at rest, once - immediately after the training work. The data obtained were analyzed using the mathematical statistics methods.
Results and conclusions. It was found that after the training work, the central contour tension index in Swimmer A decreased by almost 40%, which testified to the activation of the central contour of regulation of the heart functions. In Swimmer B this index decreased by 15% only, which indicated expressed predominance of the sympathetic channel of heart rate regulation, as well as excessive physical loading.
It was proved that the main indicator of the training level is the synchronization of the effects of the nervous and hormonal components of heart rate regulation. The high degree of synchronization of these two components of heart rate regulation indicates that physical loads are adequate to the adaptive responses of the female athletes' body.

Keywords: female swimmers, training work, physical load, physical fitness indices.

References

1. Vengerova N.N., Piskun O.E., Komissarov E.N., Klyus Yu.A. Bioimpedansny analiz sostava tela studentok kak diagnosticheskiy metod proektirovaniya fizkulturno-ozdorovitelnykh zanyatiy [Bioimpedance–based body composition rating tests for academic health physical education service design]. Teoriya i praktika fiz. kulturyi. 2018. No.  9. pp. 33-35.
2. Grigor’ev V.I. , Piskun O.E., V.M. Ivanov Perspektivy razvitiya sportivnoy nauki v rossiyskikh vuzakh [Perspectives of Development of Sport Science in Russian Universities]. 2015. No.2. pp. 34-36.
3. Bunevicius K, Sujeta A, Poderiene K, et al.: Cardiovascular response to bouts of exercise with blood flow restriction. J. Phys. Ther. Sci, 2016, 12: 3288-3292.
4. Cooper K. (1989) The aerobics program for total well-being. Physical Education and Sport. Moscow. 224 p.
5. Daniel S. Abnormal blood flow in the sublingual microcirculation at high altitude. Eur. J. Appl. Physiol. 2009. Vol. 106. pp. 473-478.
6. Drezner J.A, Ackerman M., Anderson J., et al. Electrocardiographic interpretation in athletes: the Seattle criteria. Br J Sports Med.2013. vol. 47(3). pp. 122-124.
7. Malhotra V.K., Singh N., Bishnoi R., et al. The prevalence of abnormal ECG in trained sportsmen. Med J Armed Forces India. 2015. vol. 71(4). pp. 324-329.