Dr.Biol., Professor R.V. Tambovtseva¹
I.A. Nikulina^1
1Russian State University of Physical Education, Sport, Youth and Tourism (GTSOLIFK), Moscow

Keywords: hormones, metabolism, carbohydrates, lipids, physical load, skaters, track and field athletes, pentathletes, training methods.

Introduction. Adaptive capabilities of athlete's body are affected by a number of endogenous and exogenous factors [1,2,5,6,7]. In sports practice it has been of greatest interest to study the features of body's adaptation not just to physical loads as such, but to sport-specific loads. Detection of specific adaptive changes can help improve training methods in various sports and select the most effective and informative methods of biochemical control over the changes in athletes’ physical working capacity. Determination of correlations between mobilization of the body's energy resources in the sympathetic-adrenal and pituitary adrenal cortical systems and peculiarities of maintenance of constant internal milieu during exercise helps develop scientific methodological approaches and find the most effective means that would increase the rate of the body adaptation to various loads and select the most informative adaptation level evaluation criteria. These leading systems function in conjunction with other hormonal and nonhormonal factors and actively influence the cellular autoregulation system, thus contributing to the body's adaptation to physical loads.

Objective of the study was to analyze the dynamics of concentration of energy substrates and hormones in highly-skilled athletes in different sports.

Methods and structure of the study. The research was conducted at the premises of the Muscular Activity Bioenergetics Laboratory of the Sport Biochemistry and Bioenergetics Department named after N.I. Volkov of Russian State University of Physical Education, Sport, Youth and Tourism. The experiment involved highly-skilled athletes – pentathletes (n=9), skaters (n=11) and long-distance track and field athletes (n=8), all aged from 18 to 25 years. At the time of the study all subjects were healthy and gave their written consent to participate in the experiment. Step incremental cycle ergometer test was applied. The load at the first stage was 1 watt per 1 kg of the body weight. The stages were 3 minutes long. The duration of the test was 15 minutes. Blood was tested at rest, at the time of submaximal load, at the 3rd and 10th minutes of recovery. The concentrations of insulin, somatotropin, non-esterified fatty acids, glycerin and glucose were determined in the venous blood. The lactic acid concentration was determined in the capillary blood. Urine was collected before the exercise and within 10 minutes after it. The concentration of catecholamine and its precursors was measured in urine.

The data were statistically processed using the Statistica 6.0 software and the built-in function of analysis using Microsoft Excel (2007).

Results and discussion. Table 1 presents the concentration of peptide and metabolic substrates in the blood, as well as the urinary catecholamine and dihydroxyphenylalanine excretion at relative rest in speed skaters (Group 1), track and field athletes (Group 2), and pentathletes (Group 3).

Table 1. Concentration of hormones and energy substrates in the blood and urinary catecholamine excretion at rest in speed skaters, track and field athletes, and pentathletes.

      According to Table 1, the blood insulin and adrenaline excretion in track and field athletes are significantly lower than in speed skaters and pentathletes. There are no differences between the studied groups in terms of other parameters. At the moment of submaximal load, track and field athletes and speed skaters were registered to have decreased insulin concentration as compared to the resting indices, the dynamics being insignificant in pentathletes. The somatotropin concentration increased significantly in track and field athletes and speed skaters. Meanwhile, pentathletes had a wide individual scatter in this parameter. During the exercise the adrenaline excretion increased significantly, and is was statistically significant in all studied groups. Increased noradrenaline excretion was detected in track and field athletes only. The glucose concentration trend in response to the load was opposite to the insulin kinetics. Thus, speed skaters and track and field athletes were observed to have increased glucose concentration, while in pentathletes the dynamics of this indicator was insignificant. Pentathletes had a significant increase of the non-esterified fatty acids concentration. During the exercise the changes in the glycerin level in all groups were insignificant, but the lactic acid concentration increased significantly.

         In the 3rd minute of recovery, an increase in the insulin and somatotropin concentrations in speed skaters and pentathletes was observed. In the speed skaters, the somatotropin concentration increased even more at the 10th minute of recovery. The blood glucose level was still high in the 10th minute of recovery in all the studied groups. Therefore, most of the subjects were found to demonstrate higher dynamics of hormonal changes during the transition from rest to exercise and after exercise. Differences in the responses of the biochemical systems of the body of athletes to the load were reflected in their physical working capacity. It was shown that speed skaters and track and field athletes have significantly higher working capacity as compared to pentathletes (workload in kgm/kg of the body weight: skaters: 235.6+6.8, track and field athletes: 229.0+10.3, pentathletes: 197.0+7.8, respectively, P_1-3<0.01, P_2-3<0.05, P_1-2> 0.1). Pentathletes were found to demonstrate the highest oxygen cost of work and the largest rate of specific oxygen debt. Table 2 presents the correlations between energy substrates and hormones in speed skaters, track and field athletes and pentathletes.

Table 2. Correlations between the rate processes in energy substrates and hormones in speed skaters, track and field athletes, and pentathletes.

Note: ^х – 0.1<P>0.05; * - P<0.05; ** - P < 0.01

The results obtained during the step cycle ergometer submaximal test by speed skaters, track and field athletes, and pentathletes, allowed for the conclusion that, along with the general regularities of the body's adaptation to physical load in athletes of these specializations, there are certain specific aspects of the metabolic processes that are associated with the training and competitive load specifics. Athletes’ somatotypes have no small part, too. Differences in the metabolic processes in athletes specializing in different sports are manifested both while at rest and in their bodily responses to loads. In the state of rest such differences are: lower blood insulin level and higher urinary adrenaline excretion in track and field athletes as compared to pentathletes and skaters. Long-distance track-and-field athletes, as opposed to speed skaters and pentathletes, have lower fat content [3]. Perhaps this is the reason for the low blood insulin level. In his work, E. Newsholm [4] showed that insulin secretion directly correlates with the total adipose tissue mass. By contrast with pentathletes, speed skaters and track and field athletes demonstrate higher physical working capacity while performing the test load, which is associated with highly efficient use of energy substrates and oxygen. The comparison of the specific oxygen debt rates in speed skaters, track and field athletes and pentathletes allows for the conclusion that intensity of muscular activity in pentathletes is mostly due to anaerobic processes. In pentathletes the oxygen cost of work and the maximum oxygen equivalent exceeded those in speed skaters and track and field athletes. Track and field athletes and speed skaters had their blood non-esterified fatty acids moderately increased in response to the load, which indicates a balance of mobilization and utilization of lipids, while in pentathletes the increase of the fatty acids concentration was significantly higher. In the meantime, pentathletes had an insignificant dynamics of glucose concentration, and in speed skaters and track and field athletes the glucose mobilization rate exceeded the blood glucose utilization rate, which was manifested in the increase of its concentration after the exercise. The differences in the metabolic response to the load resulted in the differences in the hormonal response. In speed skaters the activation of the sympathetic-adrenal system was mainly due to its adrenal part, in track and field athletes – due to its sympathetic part, and in pentathletes – due to both. These responses revealed a strong correlation. A negative correlation was detected in speed skaters and track and field athletes between the blood glucose and insulin, which is due to the relationship between blood insulin and glucose production by the liver during exercise. Meanwhile, a positive correlation between the glucose concentration and blood insulin was observed in pentathletes. The representatives of the studied groups have correlation dependences not only between the hormone and metabolite concentration, but also between the levels of different hormones. For example, while speed skaters demonstrate a close negative correlation between the somatotropin production and catecholamine excretion, in track and field athletes this relationship is direct, and in pentathletes it is completely lacking. The correlation analysis of the changes in the hormone and substrate concentration regardless of the sport discipline does not reveal any significant correlations in either changes in the concentration of various hormones or metabolites, which serves as additional evidence of significance of the differences in the hormonal and metabolic responses to load in athletes various disciplines, having similar qualifications and being in the same phase of the annual training cycle.

Conclusions

1. Along with the general regularities of adaptation of the body of speed skaters, track and field athletes and pentathletes to physical loads, there are certain specific aspects of the metabolic processes correlating with the training and competitive load specifics.
2. Differences in the metabolic processes in athletes in various disciplines are manifested both while at rest and in their bodily responses to loads.
3. By contrast with pentathletes, speed skaters and track and field athletes have higher physical working capacity indices during the test load, which is associated with highly efficient use of energy substrates and oxygen.
4. The comparison of the specific oxygen debt rates in speed skaters, track and field athletes and pentathletes allows for the conclusion that intensity of pentathletes’ muscle work is mostly due to anaerobic processes.
5. The activation of the sympathetic-adrenal system in speed skaters takes place mainly due to its adrenal part, in track and field athletes - due to the sympathetic part, and in pentathletes – due to both.

References

1. Volkov N.I., Nessen E.N., Osipenko A.A., Korsun S.N. Biokhimiya myshechnoy deyatelnosti. Uchebnik [Biochemistry of Muscular Activity. Textbook]. Kiev: Olimpiyskaya Literatura publ., 2013, 503 p.
2. Kremer U.J., Rogol A.D. Endokrinnaya sistema, sport i dvigatelnaya aktivnost [Endocrine system, sport and motor activity]. Kiev: Olimpiyskaya Literatura publ., 2005, 599 p.
3. Martirosova E.G. Morfofunktsionalnye osobennosti vysokokvalifitsirovannykh sportsmenov [Morphofunctional characteristics of highly skilled athletes]. Moscow: Fizkultura i sport publ., 1981.
4. Newsholm E., Start K. Regulyatsiya metabolizma [Regulation of metabolism]. Moscow: Mir publ., 1977.
5. Pogodina S.V., Aleksanyantz G.D. Adaptatsionnye izmeneniya glyukokortikoidnoy aktivnosti v organizme vysokokvalifitsirovannykh sportsmenov razlichnykh polovozrastnykh grupp [Adaptive changes in glucocorticoid activity in elite athletes of different sex and age groups]. Teoriya i praktika fiz. kultury, 2016, no. 9, pp. 49-52.
6. Tambovtseva R.V., Nikulina I.A. Izmenenie gormonalnoy regulyatsii obmennykh protsessov u konkobezhtsev na raznykh etapakh trenirovochnogo tsikla [Changes in hormonal regulation of metabolic processed in speed skaters in different phases of training cycle]. Teoriya i praktika fiz. kultury, 2015, no. 5, pp. 52- 54.
7. Tambovtseva R.V., Nikulina I.A. Osobennosti gormonalnoy regulyatsii energeticheskogo obmena u sportsmenov razlichnykh spetsializatsiy pri vypolnenii predelnoy raboty [Specifics of hormonal regulation of energy metabolism in athletes in various disciplines when training to failure]. Teoriya i praktika fiz. kultury, 2016, no. 1, pp. 28-30.

       Corresponding author: ritta7@mail.ru

Abstract

Objective of the study was to analyze hormonal regulation of carbohydrate and lipid metabolism under extreme loads in highly-skilled athletes in different sports. Subjects were tested by the incremental to submaximal cycle ergometer tests, with their venous blood being tested for insulin, somatotropin, non-esterified fatty acids, glycerin and glucose; and arterial blood tested for lactic acid at rest in the 3 and 10 minutes of recovery; and urine being tested for catecholamine. The incremental to submaximal exercise tests in application to highly-skilled skaters, middle-distance runners and pentathletes showed the following: the general regularities of the body's adaptation to the physical loads in the subjects were associated with some specific aspects of the metabolic processes correlating with the training and competitive load specifics. The tests found some differences in the metabolic processes in athletes specializing in different sport disciplines both at rest and in their bodily responses to loads.