Dr.Biol., Professor A.A. Pseunok¹
PhD M.A. Mugotlev¹
PhD, Associate Professor M.N. Silantyev^1
1Adyghe State University, Maikop

 

Keywords: adaptation, heart rate, ontogenesis, motor activity, salivary electrolytes.

 

Introduction. The cardiovascular system plays a key role in the bodily adaptation to the ever-changing environmental conditions since it acts as a limiting factor in the development of adaptive reactions of the body. Therefore, the cardiovascular system is usually the first to be examined, as, being one of the most important life support systems and an easy object for medical observations, it is often considered indicative of the functional state of the entire organism. Heart rate (HR), as well as contractile force, being both regulated by the sympathetic and parasympathetic divisions of the autonomic nervous system, are very sensitive to stress factors of any type. From this point of view, the heart rate values can be deemed the integral markers of the level of the body's stress.

Among the main factors contributing to the improvement of cardiac activity during ontogenesis is motor activity. In children's sports, it is especially important to observe the principle of adequacy: the workload should be dosed depending on the age-related functional capacities of the body. This, in turn, implies good knowledge of the specifics of the human ontogenetic development in terms of sports specialization.

Objective of the study was to obtain and analyze the test data on the heart rate and salivary electrolyte concentration in the 10-12 year-old judokas.

Methods and structure of the study. A total of 81 athletes (aged 10-12 years) were examined in the longitudinal mode at the premises of the Adygei Republican Children's and Youth Sports School of Olympic Reserve in judo, Maikop. Each respondent gave his written consent to participate in the experiment. The survey was performed at the beginning and at the end of the training macro-cycle — in autumn and spring, on the same dates, 1–1.5 hours before and after the training session. The results obtained during the study were correlated with the nature of training loads, the athletes’ sports experience, seasonal training cycle.

The HR analysis was based on the R.M. Bayevsky’s concept (1984) on double-circuit cardiac rhythm regulation. The following parameters were measured: VR (variation range), Mo (mode), AMo (mode amplitude), SI (stress index), VBI (autonomic balance index). We studied the young athletes’ adaptive capabilities under dosed physical loads (30 squats in 30 sec).

The electrolyte concentration was determined using the photocolorimetric method (CPhC-3 device) and was measured in mixed saliva 1.5-2 hours after meals. Na concentrations were determined using the microcolorimetric method (according to Albeniz and Laine), K concentrations – using a photocolorimetric micromethod (according to N. Lazarev) [5].

We calculated the Na/ K values, related to the inverse relationship with the level of activity of the sympathetic-adrenal and hypothalamic-pituitary-adrenal systems. The Na/ K coefficient was proposed by R.M. Bayevsky (1984) to assess the adaptive capacities of the body [3].

Results and discussion. Evaluation of changes in the activity of the cardiovascular system units under the influence of sports activities, both at rest and after low-intensity loading, gives the most comprehensive picture of the "cost" of the athlete's adaptation to physical loads, which enables to properly design their training process.

Improvement of the sympathetic system as a mechanism of regulation of the pumping function when adapting to muscular activity is an important factor [2].

It is the development of the sympathetic system that physical loads stimulate first, which simultaneously causes an age-related increase in the HR values. Upon reaching a certain level of development, the HR and sympathetic system indices decrease at rest, which is deemed a means of accumulation of the functional power to ensure the upcoming, more intense muscular activity [1].

The experimental data obtained during the study indicate that, throughout the first three training macro-cycles, HR in the 10-12 year-old judokas is characterized by insignificant fluctuations. By the end of the fourth macro-cycle, HR decreases significantly, though no statistically significant differences are observed [1].

The use of dosed low-intensity loads in all control tests led to an increase in the HR values, which reached the statistically significant difference ​​ by the end of the first year of study only (P<0.05). Moreover, it was accompanied by the increase in the dispersion of individual values. Such a reaction of the trained organism to the low-intensity physical loads is not quite adequate, but can be explained from the point of view of ontogenetic regularities, when excess or generalized reactions of the cardiovascular system to the stimuli are due to the hypersensitivity of the vascular bed [4].

The sympathetic effects slightly increase during the first and second macro-cycles; however, they decrease by the end of the study period (P>0.05), a similar pattern is observed in the TI values. We tend to regard this fact as favorable, testifying to the formation of a type of regulation that meets the principles of high economy of autonomous regulation, as indicated by other researchers [7].

When at rest, the parasympathetic effects change wavelike, and the oscillations are characterized by the high amplitude. It is noteworthy that both the minimum (third macro-cycle) and maximum values ​​(fourth macro-cycle) are observed in the second year of study. Throughout all four training macro-cycles, there occurs an increase in the post-exercise values of vagal influence. The shift in the autonomic balance towards the parasympathetic nervous system is also evidenced by VBI, which reached its minimum values ​​by the end of the experiment.

The shift in the autonomic balance towards the parasympathetic division after exercise leads to a "paradoxical effect" – increased HR. The above mentioned pattern is obviously due to the complex correlations between the initial activation of the autonomic nervous system units and low-power stimulation, which is a response to dosed loading. The fact that the load is performed by changing the vagal tone characterizes the subjects’ fitness level, since if the physiological "cost" of load was higher, this would inevitably lead to the reinforcement of the sympathetic effects.

The data obtained indicate that the ANS units work in concert, in accordance with the principle of "functional synergy", which means that there is no malfunctioning of the bodily systems, as should be expected in terms of overtension and failure of the adaptation mechanisms. Physical loading leads to the reinforcement of the sympathetic effects at rest - from the first to the third macro-cycle, and from the second to the fourth ones - after exercise. At the same time, the parasympathetic effects tend to increase.

The analysis of the dynamics of biochemical indicators in the 10-12 year-old judoka has shown that the concentration of chemical elements in mixed saliva decreases by the end of the fourth macro-cycle.

Higher values at the beginning of the year are, apparently, due to the heavy physical loads associated with the competitions conducted at that time. According to A.R. Bilge and E. Jobin (1998), the higher tone of the sympathetic division of the ANS plays a key role in the regulation of water-salt metabolism [9].

High concentrations of Na+ ions at the beginning of the year may be due to the increase in the urea concentrations, which indicates tension of the regulatory mechanisms during activation of the growth processes [6, 10].

The reduction in the K levels by the end of the study seems to be due to the endocrine rearrangements causing a delay of this cation and its fixation in the growing cells as a result of protein and glycogen synthesis processes [8].

Conclusion. The trainings were found to shift the autonomic balance in the 10-12 year-old judokas towards the parasympathetic nervous system, although its tone was characterized by significant fluctuations. The functional load in all control tests resulted in the increased HR, which reached its statistically significant values during the first year of study. What is more, this was associated with the increased dispersion of individual values. Such a bodily response to the low-intensity physical loads is not quite adequate, but can be explained from the point of view of ontogenetic regularities, when excess or generalized reactions of the cardiovascular system to the stimuli are due to the hypersensitivity of the vascular bed.

The research findings illustrate that in the 10-12 year-old judokas the central regulation mechanism operations are intensified at rest to effectively deplete the functionality reserves by the second year of trainings, which is expressed in the increasing number of vagotonic individuals and statistically significant decrease in the tension index.

 

References

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Corresponding author: pseunokk@mail.ru

 

Abstract

Objective of the study was to obtain and analyze the longitudinal test data on the resting versus post-exercise heart rate and salivary electrolyte concentration in the 10-12 year-old judokas (n=81), with application of the R.M. Bayevsky heart rate analyzing mathematical toolkit; and photocalorimeter KFK-3 to rate K+ and Na+ ion concentration in the saliva. The trainings were found to shift the autonomic balance towards the parasympathetic nervous system, with the central regulation mechanism operations being intensified to effectively deplete the functionality reserves by the second year of trainings. The study data and analyses show the need for the theoretically grounded preventive and health protection provisions to stabilize the children’s functionality in the training process.