Dr.Biol., professor R.V. Tambovtseva
Senior Lecturer I.A. Nikulina
Russian State University of Physical Culture, Sport, Youth and Tourism (GTsOLIFK), Moscow

Keywords: metabolic status, hormones, regulation, physical load, fitness, carbohydrate, protein, lipid metabolism.

Introduction. A point of view has spread among specialists studying the mechanisms of biochemical adaptation of human body to muscular activity and working capacity increase in the process of sports training that physical load acts as a stressor stimulating the unfolding of the mechanisms of nonspecific adaptation that include mobilization of the energy resources of the body and energy provision of functions, mobilization of the plastic reserves of the body and adaptive synthesis of enzymatic and structural proteins as well as the mobilization of defensive abilities of the body [1, 2, 4]. From this point of view a fitness status corresponds to the phase of dynamic resistance of the body to a certain type of physical load. Hormonal influences on metabolism play an important role in the unfolding of the mechanisms of adaptation to loads. Hormone as a regulator of metabolic processes is at the same time a metabolite involved in these processes, so that its concentration in the tissues and organs and the regulating effect are in inverse relation to the state of metabolism and functioning of the organs involved therein [6]. The functional activity of the endocrine glands changes considerably under the influence of physical loads. Different loads depending on their intensity, total volume, timing, performance conditions lead to creation of a system of certain relationships of various hormonal factors that provide metabolism regulation that is most efficient for a given load. The nature of the interaction of the joint effect of hormones on the course of metabolic processes and the reverse impact various interim products have on them with loads of various nature has been studied insufficiently. Currently, a large amount of factual data is accumulated on the metabolic changes that take place during the performance of physical loads of various intensity and duration [3, 5]. However, a lot of the results obtained relate to the specifics of certain biochemical processes, whereas the response of a body as a whole to a load represents a number of interrelated changes in the metabolism of all classes of compounds [6]. It is known that endogenous carbohydrate stores are spent fast during high intensity loads. The higher the load intensity, the more glycogen stores in the muscles are depleted, while during less intensive but longer loads a more substantial depletion of glycogenic reserves in the liver is detected [3]. It is known about the use of lipids in the muscular activity energetics that this process takes place if there are physical loads that do not cause an increase in the level of oxygen consumption to the maximum [8]. As for proteins, their direct use as energy sources for muscular activity is limited, but a change in the energy and hormonal status in the body could cause an increase in protein decomposition [8, 9]. A considerable decrease in glycogen stores makes it necessary to replenish them by means of gluconeogenes is that requires glycoplastic amino acids [2, 3, 8]. Disruption of the normal glycoplastic/ketogenic amino acids ratio in combination with the amount being insufficient for protein synthesis can lead to restricted synthesis and increased protein decomposition. Protein decomposition increase while being exposed to a physical load creates more or less strong stimuli for intensification of the processes of re-synthesis after its completion. Increased synthesis of various proteins – enzymatic, structural, transportation and other – is the basis of the body adaptation to muscular loads. Therefore, identification of the interconnections of carbohydrate, lipid and protein metabolism, as well as the characteristics of their regulation could contribute to the development of methodological approaches to the search for the most effective ways to increase the speed of the body adaptation to loads and the choice of the most informative criteria, based on which the current level of adaptation could be assessed. The information about the characteristics of such interconnections and the regulation of metabolism of different classes of compounds can be obtained by studying biochemical changes not only while exercising but also while resting afterwards.

The purpose of the research is to study the dynamics of the concentration of catecholamines and peptide hormones involved in both the mobilization of energy resources and plastic provision of the functionality.

Research methods and organization. The research was conducted in the laboratory of muscular activity bioenergetics at the Department of Biochemistry and Bioenergetics of Sport n.a. N.I. Volkov. Eleven highly skilled speed skaters took part in the experiment. They performed a step test with the starting load of 1 W/kg of body weight and the duration of one step being 3 minutes. The test duration ranged from 11 to 15 minutes. Heart rate and gas exchange parameters were recorded while at rest, during the test and 10 minutes of recovery after it. Blood samples were taken before the test, upon its completion and during the 3^rd minute of the recovery to determine the values of non-esterified fatty acids, glucose, insulin and somatotropic hormone. Two or three hours prior to the load and 10-20 minutes after it urine samples were collected to study the dynamics of excretion of catecholamines and their precursors.

The blood concentrations of non-esterified fatty acids were determined using the Doll's method [8], of the values of insulin and somatotropic hormone – by means of the radioimmune method, and for catecholamines and their precursors - the fluorometric method.

The research results were processed using statistical software Statistica 6.0 and built-in analysis functions of Microsoft Excel (2007).

Results and discussion. The research results are presented in Table 1.

Table 1. Reaction of the sympathoadrenal system of athletes to the load in different phases of the training cycle

* р<0.05 ** р<0.01

It has been established that epinephrine and norepinephrine, dihydroxyphenylalanine and dopamine excretion while at rest, at the beginning and at the end of the regular season does not differ significantly. In response to physical load during testing at the beginning of the season epinephrine excretion significantly increased (р<0.05), and the mediator level of the sympathoadrenal system activated too (р<0.01). Urinary norepinephrine excretion level was significantly smaller. Norepinephrine/epinephrine ratio at rest did not differ at the beginning and at the end of the regular season. In response to physical load this ratio largely decreased at the end of the season. Epinephrine + norepinephrine + dopamine/dihydroxyphenylalanine ratio decreased in response to physical load at the beginning of the regular season and remained unchanged compared with the rest level in the end of the regular season. The initial blood insulin level was significantly higher at the beginning of the season than at the end of it (р<0.05). The insulin level significantly decreased right after physical load (р<0.05) and increased after 3 minutes of recovery. The level of somatotropic hormone at rest and at the end of the regular season significantly increases (р<0.05) compared with the beginning of the regular season, but changes in response to physical load were not determined.

It has been established in the analysis of hormonal regulation of metabolic processes while athletes perform a step test, that speed skaters tend to have their insulin level dropped while glucose concentration increases as a result of the physical load. Since inhibition of insulin secretion during activity does not reduce endogenous glucose production by the liver, the speed of mobilization of carbohydrates in this case can be high, possibly higher than the speed of its utilization. A sharp increase of the level of somatotropic hormone in response to physical load this group is exposed to may provide amplified use of nonesterified fatty acids. However, we cannot deny the possible involvement of the specific adaptation of speed skaters to stress in raising the level of the somatotropic hormone. The adaptation manifests itself in the development of static strength of muscles and requires intensification of protein synthesis.

Conclusion. Determination of physical working capacity of athletes is an essential element in the organization of the training process. Sports working capacity is ensured by a complex set of various factors, among which an important place is occupied by efficiency and stability of the hormonal regulation of metabolic processes. Identification of the most informative indicators for better characterizing of the state of the humoral regulators system can be important for the sports working capacity diagnostics.

References

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8. Keul, J. Free Fettsauren, Glicerin und Trigliceride im arteriellen und femoralvenosen Blut for und nach vierwochigen korperlichen Training / Doll E., Haralambie G. // Plugers Arch. – 1970. – N 316. – P. 194-204.

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Corresponding author: ritta7@mail.ru