L.N. Botova, postgraduate
T.G. Kirillova, associate professor, Ph.D.
Volga state academy of physical culture, sport and tourism, Kazan

Key words: typological characteristics of vegetative regulation, heart rate variability, central hemodynamics, young female gymnasts.

Introduction. A load increase is being marked in the modern youth sport. The load of junior athletes is frequently higher than those for senior athletes. Therefore tight control of health and fitness shape of young athletes is to be introduced in children's sport schools along with the monitoring of their tolerance of not only training, but also competitive loads.

Given these features early diagnosis of fatigue can be made and the adaptation processes of the body of a young athlete can be traced to prevent the states of fatigue and overtraining [1-6].

Western writers often analyze in their works the impact of athletes’ gender, age and multi-purpose training sessions on the value of HRV indicators [7-10]. However, we have not found any descriptions of individual typological characteristics of vegetative regulation of heart rate in athletes in the analyzed works of western and most domestic authors.

The purpose of the study was to determine the individually-typological characteristics of vegetative regulation of heart rate and indicators of central hemodynamics (CHD) in female gymnasts aged 8–11 years old, define the correlation of the characteristics of heart rate variability and central hemodynamics in female gymnasts with different types of vegetative regulation and the specifics of response of heart rate variability and characteristics of central hemodynamics in respect to the type vegetative regulation to training load.

Research methods. We registered and analyzed 264 records of temporal and spectral indices of HRV, as well as CHD indices in female gymnasts aged 8-11 years during a week training cycle (pre-season microcycle) before and after training sessions. We used the diagnostic device "Varicard 2.51” (Ryazan town, 2008) as a data input device and the Iskim-6 software to analyze the information received. Heart rate was registered in a supine position, in the standard lead II, for five minutes. The types of vegetative regulation were determined using the classification proposed by professor N.I. Shlyk (1992). All female gymnasts were admitted to sports classes on the conclusion of medical examination, held in medical exercises dispensary.

The state of the cardiovascular system was studied using the diagnostic equipment "Valenta" (St. Petersburg, 2007) using the rheographic method. The indicators of central hemodynamics were registered using Tishchenko's integral rheography (IR) (1968). Systolic and diastolic blood pressure (BPs and BPd) were measured using a mechanical tonometer.

Results and discussion. As a result of research we have established a wide interindividual spread of HRV indices among female gymnasts aged 8-11 years. Using the individual approach to assess the type of vegetative regulation of heart rate, we relied on the idea of the double stage model of heart rate control and on the classification proposed by professor N.I. Shlyk (1992). As a consequence, we have identified female gymnasts with different states of regulatory systems: with moderately prevailing central regulation - type I (n = 22), with pronounced prevalence of central regulation - type II (n = 47), with moderately prevailing autonomous regulation - III (n = 51) and the pronounced predominance of autonomous regulation - type IV (n = 12). Certain differences were revealed when comparing the HRV indices in young female gymnasts with prevailing autonomous and central regulation of heart rate. Table 1 shows the results of the analysis of HRV in young female gymnasts aged 8-11 years, depending on the prevailing type of vegetative regulation

Table 1. Heart rate variability indicators of female gymnasts aged 8-11 years with different types of vegetative regulation at rest (M±m)

* reliability of differences relative to the type 3 equal (Р ≤ 0,05)

** reliability of differences relative to the type 3 equal (Р ≤ 0,01)

The obtained HRV data has shown, that female gymnasts with I, II and IV types of vegetative regulation differed significantly with respect to HRV indicators of female gymnasts with the type III of vegetative regulation (P ≤ 0,01). When averaging the HRV indices in female gymnasts we got the values close to the values ​​of the HRV indices of female gymnasts with the type III of vegetative regulation. Thus, averaging of HRV indices without taking into account the type of vegetative regulation is invalid because it distorts the true state of regulatory systems and, in its turn, discredits this method.

We also divided the CHD data into 4 groups depending on the types of vegetative regulation (Tab. 2). It has been found that female gymnasts with different types of vegetative regulation differ (relative to female gymnasts with the type III of vegetative regulation) and in terms of CHD indices, i.e. MBV in female gymnasts with different types of regulation is maintained with the inclusion of different mechanisms.

Table 2. Indicators of central hemodynamics of young female gymnasts (8-11 years old) with different types of vegetative regulation at rest (M±m)

* reliability of differences relative to G 3 equal (Р ≤ 0,05),

** reliability of differences relative to G 3 equal (Р ≤ 0,01)

According to Table 2 it has been found that the lowest values of MBV and SVI indices and the highest values ​​of HR and MBV indices are observed in female gymnasts with prevailing central regulation (types I and II). The high values ​​of the MBV index of these female gymnasts are supported by the high values ​​of the HR index, i.e. reduced body’s functional capacity is observed, as maintenance of the MBV level at the expense of HR is uneconomical. The lowest values ​​of HR, MBV and the highest values ​​of SV and SPR indices are observed in female gymnasts with the type IV of vegetative regulation. The optimal parameters of CHD are marked in female gymnasts with moderate activity of autonomous regulation (type III), these athletes have high functionalities of the body and can obtain high sports results. When averaging the values ​​of CHD indices we have found that the mean values ​​of these indices do not differ, except for the HR index, from the CHD indices in female gymnasts with the type III of vegetative regulation.

Analysis of the bodily response to training load is another criterion for evaluating the physical conditioning of athletes for high physical loads, including competitions (Tables 3 and 4). Female gymnasts with the type I of vegetative regulation of heart rate in most cases reacted in response to training load with the increased index of SI (p ≤ 0,05). The post-exercise tendency to increase of the value of the SV index without the rise of HR in these female gymnasts is caused by the increased strain of the mechanisms of CHD and regulatory systems.

Female gymnasts with the type II of vegetative regulation are distinguished by hyporesponsiveness of regulatory systems to training load and a mismatch of autonomous and central regulation. Consequently, these female gymnasts will most probably have low sports results. The post-exercise index of MBV to a greater extent is increased at the expense of the increase of the HR index. The SPR and PR indices in this case have not significantly changed. This response characterizes disregulatory manifestations due to the reduced functionalities of the body.

Female gymnasts with the type III of vegetative regulation of heart rate are notable for an adequate response of the cardiovascular system to a training load. Training sessions are followed by a significant increase of HR, SI (p ≤ 0,01). The increase of MBV index is due to the increase of HR and SV indices, caused by the increased sympathetic activity. The index of peripheral resistance also decreases (p ≤ 0,05) as a result of an adequate response to the increase of cardiac efficiency to reduce the load on the myocardium.

Female gymnasts with the type IV of vegetative regulation of heart rate are characterized by the rise of the strain index of regulatory systems (SI) (p ≤ 0,01), decrease of MxDMn, SDNN and the ULF index ( p ≤ 0,05). The post-exercise MBV index also tends to increase due to the rise in a greater degree of the HR index. In this case the lack of significant changes in response to the training load can be considered as the body's response to excessive or forced load for the given age.

Table 3. Heart rate variability indicators in female gymnasts (8-11 years) with different types of vegetative regulation at rest and after exercise (M±m)

** reliability of differences equal (Р ≤ 0,01)

Table 4. Indicators of central hemodynamics in female gymnasts (8-11 years old) with different types of vegetative regulation at rest and after exercise (M±m)

* reliability of differences equal (Р ≤ 0,05)

** reliability of differences equal (Р ≤ 0,01)

The present studies resulted in the allocation of the typological characteristics of vegetative regulation of heart rate and indicators of central hemodynamics in female gymnasts aged 8-11 years, revealing the interdependence of the characteristics of heart rate variability and central hemodynamics for female gymnasts with different types of vegetative regulation and determining the specific features of body response which will help sports experts in the future to control health of young athletes, optimize training load in accordance with the type of vegetative regulation  of heart rate and control athletes' tolerance of not only training, but also competitive loads.

References

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Author’s contacts: L.Botova@sportacadem.ru