Metabolic status of elite cross country skiers when developing local-muscle group endurance


Associate Professor, PhD A.S. Bakhareva1
Professor, Dr.Biol. A.P. Isaev2
Professor, Dr.Med. O.B. Tseylikman1
Associate Professor, PhD A.S. Aminov1
1Institute of Sport, Tourism and Service, South Ural State University, Chelyabinsk
2Research Center of Sports Science, South Ural State University, Chelyabinsk

Keywords: lipid metabolism, fatty acids, oxidized protein, cortisol, stress, adaptation, molecule.

Abstract. Objective of the study was to scientifically substantiate the lipid peroxidation processes and levels of antioxidant and hormonal activity in the body of athletes when developing local-regional muscle endurance.

A pooled analysis of the metabolic status of cross country skiers when developing their local-muscle group endurance is required to interpret the molecular and cellular processes. The use of ballistic and gravitational means of influence during interval training provided the concentrated development of skills in the aerobic mode and made it possible to maintain high cardiac performance in the competitive period. The relevance and social significance of the problem is unmistakable from the point of view of preservation of athletes’ psychophysiological potential and health level.

Introduction. The studies of the late 60s of the last century [8] emphasize the role of free fatty acids (FFA) as the source of energy used to power prolonged motor actions (MA) of low and moderate intensity. After training, the lipid oxidation in the body reinforces the process of oxidation of the fat component of body weight when performing motor actions to develop LRME [2]. However, we are still unaware which mechanisms additionally provide the supply of fatty acids, or the effects of training aimed at the concentrated development of LRME on the oxidized proteins and hormonal activity.

Objective of the study was to scientifically substantiate the lipid peroxidation processes and levels of antioxidant and hormonal activity in the body of athletes when developing local-muscle part muscle endurance.

Methods and structure of the research. Molecular products of lipid peroxidation were determined according to I.A. Volchegorskiy et al [6]. The study of the lipid oxidation in the isopropanol extract within the system of Fe+2 – ascorbate induction was carried out using the methodology of E.I. L’vovskaya [3]. The carbonylated protein concentration was determined by the method of E.E. Dubinina [1]. Subject to the study were cross country skiers aged 18-21 years (study group), qualified CMS (n=5) and MS (n=5) and students of similar age, including those engaged in fitness classes (reference group). All respondents consented to blood sampling. The significance of differences between the groups was determined using the Mann-Whitney test.

Results and discussion. The indicators of the metabolic status of the body of cross country skiers, presented in Table 1, indicate higher values of heptane-soluble products of LPO compared to the students from the reference group. Thus, there was an increase in the primary heptane-soluble products by 13.8% (p<0.05), in the secondary ones – by 10.5% (p<0.05).

Table 1. Concentration of isopropanol- and heptanes-soluble products of lipid peroxidation (LPO) in the blood plasma of two groups (M±m)



























< 0.05

> 0.05

> 0.05

< 0.05

< 0.05


The intergroup differences in the secondary and final isopropanol-soluble lipoperoxides were insignificant, but we observed an upward trend in the reference group. The concentration of isopropanol-soluble products of LPO-1 in cross-country skiers was 20% higher (p<0.05).

Fig. 1. Indicators of induced lipid peroxidation (LPO) in blood plasma of two groups

 At the same time, the level of antioxidant activity (Fig. 1), estimated by the concentration of secondary products of lipid peroxidation in athletes upon ascorbate induction, was 39.7% higher (p<0.01) compared to the reference group.

Table 2. Indicators of molecular mechanism of stress in two groups (M±m)


Oxidized protein

neutral, %

Oxidized protein

basic, %

Cortisol, nmol/L


40.19 ±4.56












The analysis of protein synthesis revealed that this process was more active in athletes (Table 2). Thus, basic and neutral oxidized proteins differed primarily in cross country skiers, and the difference in the intergroup values equaled 16.77% (p<0.05) and 14.97% (p<0.05), respectively. The blood plasma proteins are the most important buffer system that maintains the level of cations. Moreover, it was found that viscoelasticity of the skeletal muscles is determined by the basic and neutral proteins [4].

The level of cortisol, a stress indicator, in the study group was lower by 35.98% (p<0.01) compared to the reference one, which values were above the normal range (200-700 nmol/L). The cortisol concentration under the influence of physical exercise increased to a lesser extent in trained individuals. It should be noted that the cumulative stress syndrome covers the neuroendocrine system, neuromotor environment of MA, connective tissue processes, vegetative reactions, activation of physiological barriers, activation of granulocytopoiesis [5; 6].

Conclusion. The evaluation of intergroup metabolic parameters revealed that it was the LPO-heptane products that varied most, as the heptanes phase of lipid extracts accumulated primarily neutral fats, which led to the mobilization and oxidation of free fatty acids from fat depots and an increasing role of aerobic energy supply characterizing the development of endurance. Increased performance of the athletes’ antioxidant system against the background of the increase in the level of LPO and carbonylation of proteins, compared to the students from the reference group, leads to a decrease in the body’s stress. Consequently, motor actions, aimed at the development of LRME, level up the anxiety phase, developing increased resistance to specific and non-specific effects, and are involved in the formation of stable adaptive changes to physical exercise.

This work was supported by the Ministry of Education and Science of the Russian Federation within the basic part of the state task (project code - 1696).


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