Dr.Biol., professor I.N. Kalinina¹
Ph.D., Associate Professor V.A. Blinov¹
Ph.D., Associate Professor L.G. Baymakova¹
Ph.D., Associate Professor O.A. Blinov^2
1Siberian State Academy of Physical Culture and Sport, Omsk
²Omsk State Agrarian University named after P.A. Stolypin, Omsk

Keywords: circulatory system, heart rate variability, football players, adaptation.

Introduction. The problem of preservation and promotion of health of the younger generation is fundamental for any government, including Russia. In this context, the need for the new knowledge on biomedical subjects within the system of training of athletes is of key importance, as it is sport that places specific demands on the human body: ever-increasing load, strong motivation to the achievement of sports results and "rejuvenation" of the national team composition, doping control. In the process of training (primarily, in elite athletes) we can observe quite evident changes in the indices of individual health. Intensification of the training process is attended by the clear signs of tension of the mechanisms of adaptation of the body 4, 5, 6. In this regard, the study of the functioning specifics of the circulatory system of football players presents itself as essential and relevant, since fresh information promotes opportunities of biomedical science specialists for the development of the means of recovery and rehabilitation of the previously mentioned group of athletes [7].

The purpose of the research was to study the specifics of functioning of the cardiovascular system of football players of mass categories at rest and during the active orthostatic test.

Materials and methods. The study was conducted at the premises of the Departments of Medicobiological Foundations of PC&S and Theory and Methodology of Football and Hockey of FSBEI HPE Siberian State Academy of Physical Culture and Sport. 89 football players of mass categories and 40 young men not involved in sports (control group) were examined. The functional state of the cardiovascular system was analyzed using a number of methods and functional tests (stress testing with active orthostatic test - AOT) by means of the rheographic complex Reo-Spectrum-2 by "Neurosoft" using the "Poly-Spectrum" software. Prior to testing, the body length and body mass were measured, and these data were captured. Systolic and diastolic blood pressure (BPs and BPd, respectively) and heart rate (min-1) were recorded using the Omron MX blood pressure monitor. Pulse pressure (PP) was measured by calculating the variance between BPs and BPd.

We detected and standardized the following cardiac performance indices:

- SV (ml) - characterizes the volume of blood pumped from the left ventricle into aorta per beat;

- CO (l) - the volume of blood pumped from the left ventricle into aorta per minute;

- TPVR (c.u.). - total peripheral vascular resistance;

- DP (c.u.) - double product as a measure of the mechanical work done by the heart and the circulatory system in general, calculated by the Robinson formula [8].

In order to estimate the level of the functional state of the circulatory system and determine the adaptive capabilities of the body we used an estimate indicator – index of functional changes (IFC) [1].

Cardiointervalography was taken in the supine position after 5 min rest following the procedure proposed by R.M. Baevsky (1984), in a minute - in active orthostasis using the Reo-Spectrum-2 rheographer by “Neurosoft” and the "Poly-Spectrum" software. The vegetative homeostasis was analyzed by means of the methods based on the statistical transformations: spectral analysis of heart rate; variation pulsometry; integral method (evaluation of the adequacy of regulatory processes). During the spectral analysis, we were guided by the values provided by the international standard of heart rate variability (1996). The integrated assessment of heart rate variability was carried out basing on the index of activity of regulatory systems (IARS) with the calculation of the point total on five criteria [2]. We described the vegetative tonus and determined the driving regulatory mechanisms by the methodology of A.M. Wayne (2000), where LF>VLF<HF - unstressed vegetative balance, VLF>LF<HF - stressed vegetative balance, VLF>HF<LF - sympathicotonia (relative or absolute), LF<HF>VLF - relative vagotonia [3] .

All the studies were carried out in the morning before academic studies and physical loads in compliance with the basic requirements to the hygienic conditions, with due regard to the counterindications and testing rules. We excluded from the rhythm under study all artifacts and ectopic rhythms, all transients, non-stationary sections of rhythmocardiogram, stipulated by swallowing, separate deep breathes, hacking [9,10].
The statistical data processing was made using the STATISTICA 6.0 software package.

Results and discussion. The study of the basic hemodynamic characteristics of football players of mass categories revealed the following: when at rest, the functional state of the cardiovascular system of the specified group of athletes can be defined as "satisfactory". The hemodynamic situation is characterized by normal values, HR, SV and CO against the background of normotension in relation to due values and indices in people not engaged in PC&S (Table 1). The values of the Robinson index (DP, c.u.) indicate good myocardial perfusion and normal, without stress, mechanical work done by the heart. The IFC values received in the group of football players were within the range, characterizing the state of satisfactory adaptation, and those obtained in the control group testified to some tension in the adaptive systems (2.09±0.0 and 2.5±0.0 c.u., respectively).

We used the active orthostatic test to assess the functional adequacy of the reflex mechanisms and excitability of the sympathetic nervous system [11]. In active orthostasis, football players demonstrated "good" tolerance to the test with an increase in their heart rate by an average of 22%, while the control group was observed to have a "slight hyperreaction", their heart rate increased by about 31.2%. The changes in the hemodynamic characteristics of football players, though being statistically significant, did not exceed the standard values in healthy people not engaged in PC&S.

Table 1. Basic hemodynamic characteristics of football players at rest and during active orthostatic test

Note: * – significance of differences at p<0.05 between the indices in football players and control group; ^ – significance of differences at p<0.05 when at rest and during AOT; 1 – background values, 2 – AOT values.

The spectral analysis of HRV makes it possible to determine its periodic components and display the ratio of different constituents, reflecting the activity of particular units of the regulatory mechanism. As part of the study we examined the following indices: heart rate spectrum total power (TP, ms²), power (ms²) and relative power (%) of high frequency (HF), low frequency (LF) and very low frequency (VLF) waves, as well as the percentage of general spectrum indices in %.

The comparative analysis of the basic indices of HRV revealed the following: the values of the spectrum total power at rest and during AOT indicate good functional state of the cardiovascular system. According to the studies by V.M. Mikhaylov (2000, 2005), such condition is characterized by strongly pronounced cardiac impulses within all ranges, fluctuations of the spectrum total power within the range of 1500-2500 ms², LF/HF coefficient values in the zone 0.5-1.1 and the percentage component in the general spectrum of waves VLF<45%, which fully coincides with the obtained data, except for the TP values. It should be noted that the increment of this index in athletes is treated as normal and indicates good adaptive capability, which, apparently, was suggested by our study.

During AOT we detected some tension in the vegetative balance in both groups, which was expressed in the change of the spectral component ratio from HF>LF>VLF to LF>VLF>HF. The percentage distribution of the general spectrum at rest for VLF was equal to 27.7±0.7% for football players and 28.5±0.3% for the control group, for LF - 31.6±0.6 and 37.5±0.3%, for HF - 40.5±0.7 and 34.2±0.3%, respectively (Table 2).

Table 2. Basic indices of heart rate variability of football players at rest and during AOT

Note: * – significance of differences at p<0.05 between the indices in football players and control group; ^ – significance of differences at p<0.05 when at rest and during AOT; 1 – background values, 2 – AOT values.

The values of the index of activity of the regulatory systems, reflecting tension of the functional state of the football players' body, equaled 1-2 points, which testifies to good condition of its functional systems, whereas in the control group IARS ranged between 3-4, thus indicating tension in the adaptive systems.

Conclusion. The findings could be used when monitoring the functional state of the body of football players in different phases of the training cycle.

References

1. Baevsky, R.M. Donozologicheskaya diagnostika v otsenke sostoyaniya zdorov'ya (Preclinical diagnostics for health status evaluation) / R.M. Baevsky, A.G. Berseneva. – St. Petersburg, 1993. – 200 P.
2. Baevsky, R.M. Otsenka adaptatsionnykh vozmozhnostey organizma i riska zabolevaniy (Estimation of adaptation capabilities of the body and risk of disease) / R.M. Baevsky, A.G. Berseneva. – Moscow, 1997. – 235 P.
3. Vegetativnye rasstroystva: Klinika, lechenie, diagnostika (Autonomic disturbances: clinical picture, treatment, diagnostics) / Ed. by A.M. Vein. – Moscow: Meditsinskoe informatsionnoe agentstvo, 2000. – 752 P.
4. Geselevich, V.A. Aktual'nye voprosy sportivnoy meditsiny: izbrannye trudy (Topical issues of sports medicine: Selected works) / V.A. Geselevich / Comp. by G.A. Makarova. – Moscow: Sovetskiy sport, 2004. – P. 200.
5. Dembo, A.G. Sportivnaya kardiologiya: rukovodstvo dlya vrachey (Sports cardiology: doctor's guide) / A.G. Dembo, E.V. Zemtsovskiy. – Leningrad: Medicina, 1989. – 464 P.
6. Dibner, R.D. Kardiologicheskie problemy massovogo sporta (Cardiological problems of mass sport) / R.D. Dibner // Sport i zdorov'e (Sport and Health). – St. Petersburg: LNIIFK, 1992. – P. 37–41.
7. Kalinina, I.N. Optimizatsiya ozdorovitel'nykh meropriyatiy u lits, imeyushchikh narushenie krovoobrashheniya nizhnikh konechnostey, s razlichnym urovnem dvigatel'noy aktivnosti (Optimization of recreational activities for persons with poor circulation in the legs with different levels of motor activity) / I.N. Kalinina, N.A. Braun, S.Yu. Kalinin // Prirodnye i intellektual'nye resursy Sibiri (SIBRESURS-12-2006) (Natural and intellectual resources of Siberia (SIBRESURS-12-2006). – Tomsk, 2006. – P. 442–445.
8. Kalinina, I.N. Gendernye osobennosti vegetativnogo statusa u zdorovykh lits v vozraste 15-60 let (Gender characteristics of vegetative status in healthy subjects aged 15-60 years) / I.N. Kalinina //Variabel'nost' serdechnogo ritma: teoreticheskie aspekty i prakticheskoe primenenie: Mater. IV Vseros. simp. s mezhdunar. uchastiem (Heart rate variability: theoretical aspects and practical application": Proc. IV All-Russia symp. with int. participation) November19-21 2008. – Izhevsk, 2008. – P. 121–124.
9. Makarova, G.A. Prakticheskoe rukovodstvo dlya sportivnykh vrachey (Practical guide for sports physicians) / G.A. Makarova. – Rostov-on-Don, 2002. – 800 P.
10. Mikhaylov, V.M. Variabel'nost' serdechnogo ritma: opyt prakticheskogo primeneniya (Heart rate variability: experience of practical application) / V.M. Mikhaylov. – Ivanovo, 2000. – 200 P.
11. Mikhaylov, V.M. Kolichestvennaya otsenka urovnya zdorov'ya v vosstanovitel'noy meditsiny (Quantitative assessment of health level in rehabilitation medicine) / V.M. Mikhaylov. – Sochi: Neurosoft, 2005. – 60 P.
12. Oshevenskiy, L.V. Izuchenie sostoyaniya zdorov'ya cheloveka po funktsional'nym pokazatelyam organizma: metod. ukazaniya (Study of state of health based on functional parameters in men: instructional guidelines) / L.V. Oshevenskiy, E.V. Krylova, E.A. Ulanova. – Nizhny Novgorod, 2007. – 38 P.

Corresponding author: kalininirina@yandex.ru