PhD, Associate Professor A.B. Petrov¹
PhD, Associate Professor A.N. Denisenko¹
PhD, Associate Professor M.V. Baranova¹
M.D., D.Sc. (Medicine), Professor A.L. Pokhachevskiy^{2, 3}
M.D., D.Sc. (Medicine), Professor S.V. Bulatetsky^3
1State Lesgaft University of Physical Culture, Sports and Health, St. Petersburg
²I. M. Sechenov First MSMU MOH Russia (Sechenovskiy University), Moscow
³RyazSMU, Ryazan

Keywords: autonomous nervous system, spectral analysis of heart rate.

Introduction. Thanks to the formation of the functional system (FS), which determines the synergistic relationship of the adaptive reserves of the body, it becomes possible to perform motor activity of any complexity and intensity. In turn, it is likely that the physical qualities (FC) formed with the participation of different FS should be implemented in different ways.
The aim of the study is to identify the physiological mechanisms underlying FC "flexibility".
Methodology and organization of the study. The functional state of athletes-polyathletes, track and field athletes, wrestlers (49 people) was studied by means of a frequency analysis of the heart rate during an active clinoorthostatic test and flexibility testing [1]. The main test exercise is "leaning forward from a standing position with straight legs". The choice of this exercise is determined, first, by its versatility for a healthy person; secondly, the peculiarity of adaptive processes, when a rapid change in the position of the body in space: the transition from the vertical position to the position " upside down» - requires the mobilization of additional adaptive reserves of the body; thirdly, the identified features during the pilot study among athletes of basic sports with the inclusion of various test exercises for flexibility: this exercise demonstrated predominant and virtually equal relationships with the functional state of the body, regardless of specialization.
The results of the study and their discussion. Significant correlations (Spearman) of the adaptive characteristics of the athletes ' body with the results of test exercises were revealed. The moderate association with the humoral-metabolic component of clinostasis (0.54) is probably determined by the need for pre-start hormonal (adrenal adrenergic) mobilization, which will be realized during the exercise. The latter assumption is confirmed by the association of a high level with % VLF in orthostasis (-0.77). The need for pronounced sympathetic support, realized in orthostasis (0.74), also confirms its sympathoadrenal basis.
Conclusion. The physical quality of "flexibility" is provided in athletes by the need for humoral and metabolic support in a state of relative physiological rest and is realized by a pronounced sympathetic connection during orthostasis. Parasympathetic involvement appears in a moderate association with the autonomic balance marker (HF/LF). The results obtained indicate that the implementation of FC "flexibility" in various FS has a related basis and is, in fact, a cross-adaptation effect.

Literature

1. Mikhailov V. M. Quantitative assessment of the current functional state under stress / V. M. Mikhailov, A. L. Pokhachevsky, E. V. Pokhachevskaya / / Pathological physiology and experimental therapy. - 2006. - No. 2. - p. 19-21.