Associate professor, Ph.D. V.V. Zebzeev
Associate professor, Ph.D. O.S. Zdanovich
Tchaikovsky State Institute of Physical Culture, Tchaikovsky

Keywords: body composition indicators, Nordic combined athletes, training loads of different orientation.

Introduction. Currently, due to the rapid development of computer technologies in sports modern integrated methods are being actively introduced, thus making it possible to evaluate a number of indicators of athletes' fitness within the shortest possible period of time and most efficiently [3].

In this regard, research related to the evaluation and analysis of body composition of athletes attracts special attention. The study of body composition is a relatively new branch of sports science, which dates back to the beginning of the last half of the XX century. Body composition should be understood as division of body mass by a certain number of interrelated components such as, for instance, the level of intracellular and extracellular water, protein and mineral content, fat and lean body mass, skeletal muscle mass, etc. [2].

The information obtained during the body composition analysis of athletes can potentially be interesting for trainers, as they can use it to adjust the training process for Nordic combined athletes. Thus, upon the corresponding diagnostic procedure a trainer gets the information on the ratios of muscle and fat mass, water and minerals in an athletes' body. Moreover, he/she can estimate nutritional balance, develop recommendations on physical exercises, etc.

As far as athletes are concerned, day-to-day information on body composition helps them, firstly, control their body mass, and secondly, lose weight at the cost of fat and excess water, without interfering with their health. It should be noted that recovery after exercises of different purposes proceeds differently. Unfortunately, there are no data in the theory and practice of training of Nordic combined athletes to assess the degree of involvement of a certain component of body composition of athletes during training impacts of different purposes.

In prior years, determination of body composition of athletes was mainly limited to estimation and diagnostics of fat tissue. For this purpose they commonly used various body-weight ratios and body mass indices (Quetelet, Kaup, Gould et al.), based on evaluation of the external dimensions of the body [1]. However, recently similar studies have been carried out using professional analyzers of body composition. "InBody 720" is one of them [2].

"InBody 720" operates basing on the method of multi-frequency bioelectrical impedance analysis (BIA). Insensible electrical impulses are transmitted through the body of an athlete, and then impedance characterizing their transmission through various body tissues is measured. Since there is a rather singnificant difference in impedance of different tissues, the measurements obtained give a comprehensive idea of the human body composition [2].

The purpose of the study was to analyze the indicators of body composition of Nordic combined athletes (7 skilled athletes aged 17-20 years) after exercise of different purposes.

Materials and methods. The experimental work was done at the premises of the Federal Winter Sports Training Center "Snezhinka", which is a part of the organizational structure of Tchaikovsky State Institute of Physical Culture. 7 Nordic combined athletes aged 17-20, athletes of the Specialized Children and Youth Sports School of the Olympic Reserve "Start" and TchSIPC sports team, who had the qualifications of the 1^st grade, CMS and MS, were involved in the study. Body composition of Nordic combined athletes was estimated from August 4^th through August 9^th, 2014.

The peculiarities of training of Nordic combines athletes during the study were as follows. Thus, the microcycle training plan for Nordic combined athletes consisted of 6 training days, while training sessions were conducted once a day and lasted 1.5-2 hours. On Monday and Friday the athletes were busy practicing the V1 and V2 skating techniques at the distance of 30 km, mostly in the aerobic mode. On Tuesday and Thursday athletes were mastering the K-95 ski jumping technique, mostly in the alactate anaerobic mode, with that each Nordic combined athlete performed 10-12 jumps. In turn, training sessions on Wednesday and Saturday were focused on increasing the level of special physical fitness. Nordic combined athletes performed a great number of exercises simulating the ski jumping technique (or its separate phases) and skiing, primarily in the anaerobic-aerobic mode.

Body composition of athletes was estimated as directed by the device manual. Thus, the study was conducted at the temperature of 20-25C^o, athletes were in the same position during the procedure.

Table 1. Results of body composition analysis of Nordic combined athletes after training loads of different purposes

Results and discussion. The results of the analysis of the body composition of Nordic combined athletes aged 17-20 (Table 1) have revealed that the greatest changes in the studied indicators were registered after aerobic exercises, which were as follows: 0.9 l decrease of the mean values of intracellular water, compared with the baseline values obtained before the training sessions, 0.4 l reduction of the level of extracellular water, 0.6 kg decrease of protein content, 0.31 kg – of mineral content, 0.6 kg – of fat mass, 1.3 l - of total body water content, 0.6 kg – of lean soft tissue mass, 0.8 kg - of lean body mass (p<0.05).

The changes in the body composition indicators of Nordic combined athletes after anaerobic-aerobic exercises were less significant compared to the results obtained after aerobic training sessions, but more significant compared to the results obtained after alactate anaerobic training sessions. As seen from the registered changes, the mean values of intracellular water decreased by 0.5 l, the level of extracellular water - by 0.2 l, protein content - by 0.4 kg, mineral content - by 0.19 kg, fat mass - by 0.4 kg, total body water content - by 0.7 l, lean soft tissue mass - by 0.3 kg, lean body mass - by 0.4 kg (p<0.05).

The analysis of the similar indicators, registered after alactate anaerobic exercises, compared with the results obtained before the training sessions, indicates an insufficient impact of the given training load on the body composition indicators of Nordic combined athletes, as evidenced by the statistically significant (p<0.05) decreases in the mean level of total body water content and intracellular water by 0.4 and 0.3 l respectively, while the rest of the changes in the indicators of body composition of athletes were proved to be insignificant (р>0.05).

It has been established in the analysis of the ratio between the muscular and fat tissues of Nordic combined athletes (Table 2), after training primarily aerobic loads athletes' mean weight decreased significantly by 1.4 kg, and the muscular and fat tissue mass - by 0.5 kg (p<0.05). The changes in the studied indicators after loads performed by Nordic combined athletes mostly in the anaerobic-aerobic mode were significant as well: athletes' mean weight decreased significantly by 0.6 kg, muscular tissue mass - by 0.3 kg, fat tissue mass - by 0.4 kg (p<0.05). All changes registered in relation to the muscular and fat tissues in Nordic combined athletes after mostly alactate anaerobic loads were insignificant (p>0.05): mean weight decreased by 0.2 kg, muscular tissue mass - by 0.1 kg, and fat tissue mass - by 0.2 kg.

Table 2. Results of the study of the ratio between muscular and fat tissues of Nordic combined athletes after training loads of different purposes

Conclusion. The major changes in the indicators of body composition of Nordic combined athletes were registered after aerobic training sessions and were significant. The changes in the body composition indicators after anaerobic-aerobic training loads turned out to be less significant compared with the results obtained after aerobic training sessions, but more significant compared with those obtained after alactate anaerobic workouts. In turn, alactate anaerobic training impacts had an insignificant effect on the components of athletes' body composition.

References

1. Guba, V.P. Osnovy sportivnoy podgotovki: metody otsenki i prognozirovaniya (morfobiomekhanicheskiy podkhod): nauch.-metod. posobie (Fundamentals of sports training: methods of assessment and prediction (morphobiomechanical approach): teaching aid) / V.P. Guba. – Moscow: Sovetskiy sport, 2012. – P. 47–83.
2. Zebzeev, V.V. Analiz sostava tela prygunov na lyzhakh s tramplina (Ski jumpers' body composition analysis) / V.V. Zebzeev, O.S. Zdanovich // Sb. mater. nauch.-prakt. konf. «Paralimpiyskoe dvizhenie v Rossii na puti k Sochi-2014: problemy i resheniya (Proceedings of theor.-pract. conf. "Paralympic Movement in Russia towards Sochi 2014: Problems and Solutions"). – St. Petersburg: Pub. h-se of SPbNIIFK (SPbSRIPC), 2013. – P. 40–44.
3. Zebzeev, V.V. Dinamika funktsional'nogo sostoyaniya lyzhnikov-dvoebortsev v ramkah mikrotsikla (Functional state dynamics of Nordic skiers within microcycle) / V.V. Zebzeev, O.S. Zdanovich // Uch. zap. un-ta im. P.F. Lesgafta. – 2014. – № 12. – P. 74–78.

Corresponding author: zebzeev85@mail.ru