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11THE INFLUENCE OF SPORTS LOADS ON FUNCTIONAL STATE AND REGULATORY ADAPTABILITIES OF CARDIOVASCULAR SYSTEM OF YOUNG BASKETBALL PLAYERS IN VIEW OF SOMATOTYPOLOGICAL CHARACTERISTICS
A.V. Shakhanova, professor, Dr.Biol.
A.A. Kuz'min, Ph.D.
Yu.Yu. Dautov, professor, Dr.Med.
T.G. Petrova, Ph.D.
Adyghe State University, Maikop
Keywords: cardiovascular system, heart rate variability, regulatory and adaptive status, somatotype, young basketball players.
Introduction. Arrangement of efficient conditions for health formation is possible only in the course of continuous physical education. Continuity reflects the pattern of its construction as an integrated system of formation of personal physical culture of people of all ages, ensuring that a person adopts the values of physical culture and is willing to work and defend the country. The last point defines a new goal set of the state policy in the field of physical culture and sport, stated in the decree of the President of the Russian Federation dated March 24th, 2014, "On the All-Russian sports complex "Ready for Labor and Defense" (RLD)". Since Mr. Putin stressed the need to develop mass sports, the major tasks of scientists in the field of pediatric exercise physiology are to find optimal training regimen, improve physical working capacity and prevent states of deadaptation, including those caused by sports hyperkinesia [1, 6]. All this contributes to raising the question of compliance with the principle of adequacy: the load should be dosed according to the age-related functional and adaptive capabilities of the body. The concept of adequacy of physical load brings together all adaptive properties of adaptive functional systems, mainly the cardiovascular one, being the basic functional system of homeostatic and adaptive levels, especially in children [2, 3].
Given that the morphofunctional and adaptive development of young athletes are closely related, and somatotype is an integrated model of the vital activity of the body characterizing the individual aspects of physical condition, it was interesting to consider heart rate variability depending on somatotype. The study of this problem will give a chance to approximate the issue of individual adaptation, provide for using in the training process sports load adequate to child's regulatory and adaptive status, motivate schoolchildren for team sports classes [3].
The purpose of the research was to provide a scientific substantiation of functional and regulatory and adaptive capacities of young basketball players aged 10-15 years with different somatotypes in the dynamics of the training process.
Materials and methods. The experiment was conducted in a longitudinal mode during 3 years with the same children and adolescents who regularly played basketball in the regimen of sports clubs of the Children's and Youth Sports School of Olympic Reserve (CYSSOR) of the town of Maikop.
A total of 60 boys aged 10-15 were examined. In addition to sports history, their health history was also studied carefully. Virtually healthy children were involved in the experiment on a voluntary basis. In order to standardize the conditions all the research was conducted in the morning hours (9 am to 12 pm) in the comfort temperature conditions (18-20oC) at the premises of the Laboratory of Child Developmental Physiology of the Research Institute for Complex Problems of Adyghe State University. The examination took place twice a year: in autumn (October - November) and in spring (March-April), because it is in these times that an optimal level of adaptation to physical load is observed or, conversely, fatigue develops in case of irrationally planned training sessions.
Whilst assessing the age we proceeded from the guidelines of A.V. Stavitskaya and D.I. Aron. In accordance with the age periodization, recommended by the Institute of Developmental Physiology of the Russian Academy of Education (1965), during somatotype analysis the examined contingent was divided into two age periods of development: second childhood (10-12 years old) and adolescence (13-15 years old).
Assessment of physical working capacity and general endurance of young basketball players included:
• determination of physical working capacity under the conditions of the PWC170 test;
• determination of maximal oxygen consumption (MOC).
To determine PWC170 we used a hardware-software complex "Poly-Spectrum-Ergo" ("NeuroSoft", Ivanovo). The PWC170 load was modeled on a cycle ergometer and controlled using an ECG (electrocardiograph «Poly-Spectrum-12»). PWC170 and MOC in relative units per kilogram of body weight were calculated in the automatic mode by the "Poly-Spectrum" program in accordance with the formula of V.L. Karpman.
The vitro-study of the wave structure of heart rate variability was carried out in compliance with the requirements stipulated in the International standard for short records. The electrocardiogram was recorded using the hardware-software complex «Poly-Spectrum-12». Rhythmograms obtained were controlled manually to avoid possible artifacts. The power of VLF-waves reflecting the cerebral ergotropic component, of LF-waves (sympathetic effect) and of HF-waves (parasympathetic effect) in the spectrum of heart rate variability was measured as a percentage of the total spectrum power (TP).
Based on the integrated analysis of somatic indicators, with the help of the computer program "Anthropometry" designed by the method of N. Shevkunenko in the version of S.Yu. Morgal'ev, the young football players were divided into three somatotypes within each age developmental period (second childhood and adolescence): brachymorphic (B), mesomorphic (M) and dolichomorphic (D). Depending on the somatotype of the subjects the data obtained were analyzed with regards to physical working capacity (PWC170, kgm/min/kg), general endurance (MOC, ml/min/kg) and heart rate variability.
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Results and discussion. While studying the spectral components of heart rate variability at rest in young basketball players attention was drawn to the prevalence of the high-frequency component of the spectrum (HF-waves) indicating the parasympathetic effect on heart rate in all age groups (Figure 1). High orthostatic tolerance was detected in this age period.
This indicates that young basketball players aged 10 and 11 had no state of stress of the regulatory mechanisms, we had detected in earlier studies of young football players and non-athletes [5]. The results obtained are consistent with the ones in the studies involving young athletes conducted by a number of authors in which the heart rate structure was proved to change while at rest under the influence of adequate extended motor mode, indicating that new, more favorable relationships are being established such as: reduction of sympathetic and strengthening of parasympathetic effect on the heart. It is revealed that in the framework of basketball training the parasympathetic effect on the heart rate regulation starts to prevail at the age of 10-11 years, resulting in the effectivization of physiological functions and reduction of the physiological "penalty" for the achieved adaptive result.
It is of particular importance that at the age of 12 the young basketball players had a vagal surge (HF-waves) accompanied by a decrease of the effect of the central link (VLF-waves) of regulation and sympathetic effect (LF-waves). This fact is consistent with our earlier findings in the studies of the wave structure of heart rate regulation of young football players and non-athletes, which suggests that the age of 12, regardless of the mode of motor activity, is crucial for male ontogenesis regarding formation of vagal mechanisms of cardiac function regulation. This is confirmed by the data showing that at the age of 6-11 years the sympathetic innervation has a more pronounced effect on the heart rather than parasympathetic, but by the age of 12 the parasympathetic tonus increases.
At the same time, tension of the vegetative mechanisms of the cardiac function regulation was detected in young basketball players aged 12 years during the orthostatic test. This is quite logical, because young basketball players' pubertal growth spurt occurs earlier with regards to the age of 13 that is set by the normal course of ontogenesis, namely to the age of 12 when the heart is getting ready for work in the conditions of the new morphological situation.
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Figure 1. Indicators of heart rate variability of young basketball players aged 10-15 years at rest and during the orthostatic test
The results obtained both at rest and during the orthostatic test give grounds to believe that at the age of 12 young basketball players undergo a number of quantitative and qualitative age-related changes in the body functioning.
It was found that at the age of 14-15 years young basketball players experience vegetative balance stabilization against the background of high orthostatic tolerance. A similar situation of optimization and stabilization of the ratio of autonomy (HF-, LF-waves) and centralization (VLF-waves) in the regulation of heart rate was observed in young football players aged 13-15 years [3]. Later in time stabilization of the vegetative balance in young basketball players is probably due to the intensified phenomenon of intersystem and intra-system heterochrony against the background of an earlier pubertal growth spurt at the age of 12. The pubertal growth spurt period is always accompanied by a increased heterochrony phenomenon and a state of desynchronosis [6]. As seen from analysis of the somatotypes distribution according to the dimensional variation level of total body size, young basketball players of all age groups have a stable prevalence of the dolichomorphic somatotype (D-type) - 73.3% of the subjects in the second period of childhood and 73.6% of the subjects in adolescence. The mesomorphic somatotype (M-type) of young basketball players tended to decrease with age and rising fitness level. In the period of second childhood it was registered in 20.0% of cases, while in adolescence this number dropped to 13.4%. The brachymorphic somatotype (B-type) was observed in only 6.7 % of young basketball players in the period of second childhood and in 10.0% of those in adolescence, i.e. the number of young basketball players having it was the smallest.
As for the young basketball players at the age of second childhood, the M-type representatives had some advantages in terms of physical working capacity and general endurance as compared to D-type ones (p>0.05). Nevertheless, in the spectrum of the cardiovascular function regulation no strain of regulatory mechanisms was observed in the M-type representatives, while the D-type ones had a tendency to centralized heart rate regulation, that indicating the development of tension of regulatory systems. The difference in physical working capacity and general endurance indicators of the M and D types leveled with age and increase of fitness level, but a more progressive dynamics of growth of physical working capacity was noted among the D-type representatives compared with those of M-type. Moreover, it took place on the background of increasing centralization of heart rate regulation, thus the physiological "penalty" of the bodies of the D-type representatives for the achieved level of physical working capacity was bigger, which is quite natural as the prevalence of longitudinal body sizes over lateral in the development of young basketball players enhances the phenomenon of intersystem heterochrony and a less stable type of regulation of adaptive processes in the body is formed.
The B-type representatives had the lowest values of physical working capacity and general endurance, the sympathetic effect (LF-waves) dominated over parasympathetic one (HF-waves) in the heart rate
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spectrum and the suprasegmental centers of the cardiac function (VF-waves) were highly active. Despite the fact that with age and increase in sports experience physical working capacity and general endurance were improved in this group, this was accompanied by considerable strain of the cardiac function regulation mechanisms testifying to the high physiological "penalty" for adaptation.
Conclusions. As part of the basketball training the parasympathetic heart rate regulation starts to dominate at the age of 10-11 years, which provokes the effectivization of physiological functions, reduction of the physiological "penalty" for the achievement of adaptive result. The age of 12 is a crucial period in the male body development in basketball training when the vagal mechanisms of cardiac function regulation are finally set. In order to improve the morphofunctional state of young basketball players, to prevent the development of the state of deadaptation in this age period the volume of physical activity should be decreased as it can lead to a breakdown in adaptation and as a consequence to deterioration of health of children of this age group. At the age of 14-15 young basketball players experience stabilization of vegetative balance on the background of high orthostatic tolerance, which is considered to be the most optimal combination of centralization and autonomy of heart rate control. With regards to the basketball training, the M- and D-type representatives did not really differ in terms of the level of physical working capacity and general endurance, and young basketball players of D-type experienced growth of the physiological "penalty" for adaptation to physical load. Representatives of the brachymorphic somatotype, whose low values of PWC170 and MOC are combined with high tension of cardiac function regulation mechanisms, are in the risk group. This risk group is recommended to reduce physical load to avoid deadaptation processes.
References
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