[Bioimpedance analysis of body composition and rest energy expenditure in highly trained cross-country skiers].

The body composition monitoring using bioimpedance analysis (BIA) is important in assessing the functional state of athletes in sports. Based on changes of body composition, it is possible to optimize the actual dietary intake, as well as successfully organize the training process. The purpose of this research was to conduct a comparative assessment of BIA parameters and rest energy expenditure (REE) in highly trained cross-country skiers and young non-athletes. Material and methods. The members of the national cross-country skiing team from the Komi Republic and Russian Federation (n=30; age - 22.3±2.7 years) were examined. Practically healthy medical students served as a control group for the present study (n=40; age - 20.2±2.4 years). The participants successively passed the following study steps: assessment of the body composition by BIA (ACCUNIQ BC380), REE determination by indirect non-fasting calorimetry and calculation technique. Results. The parameters of total body water, fat-free mass, lean tissue and body cell mass were higher in contrast to the fat mass percentage in the athletes (р<0.001). The calculated REE was lower than measured REE among all the participants. At the same time, the REE calculated by the Ketch-McArdle formula significantly differed between the groups, while no differences were found between the REE calculated by the Harris-Benedict prediction equation. The measured REE were significantly higher by 16% (p<0.001) i n athletes compared to those in the control group. Conclusion. The body composition of athletes was distinguished by a significantly higher amounts of total body water, fat-free mass, skeletal muscle, active cell mass, and lower percentage of fat mass compared to healthy untrained individuals. The results obtained among athletes coincided with the idea that the magnitude of REE is determined by the mass of metabolically active tissues and to a lesser extent depends on the fat mass. BIA results can be used to monitor athletes' body composition during the training process.

[Contemporary approaches to the assessment of energy intake and energy expenditure in athletes].

Assessment and interpreting of the energy expenditure (EE) in highly skilled athletes are important components of an effective training and performance prediction. Each component of EE (resting energy expenditure, thermic effect of food, and physical activity energy expenditure) is closely related to dietary patterns, the intensity and duration of physical activity, as well as a number of other factors that affect the functional state of athletes. Despite the importance of EE in the training process, coaches and athletes often do not take EE into account, which reduces the objectivity of assessing athletes' functional state. The purpose of this research was to summarize the recent information on the structure of EE and energy consumption in athletes. Material and methods. The search and analysis of publications was carried out using the PubMed, MEDLINE, Scopus, Web of Science, eLIBRARY databases, mainly for the last 10 years, using the search keywords: rest energy expenditure, thermic effect of food, physical activity energy expenditure, energy intake, total energy expenditure, athletes. Results. This overview includes information on the components of total energy expenditure, such as rest energy expenditure, thermic effect of food and physical activity energy expenditure, as well as generalized information on the factors affecting the variability of their values and methods for assessing one or another type of energy expenditure. International nutritional recommendations regarding the level of physical activity of athletes are systematized, as well as the advantages and disadvantages of methods for studying energy consumption and total energy expenditure are presented. Conclusion. Combined study of energy intake and energy expenditure will help athletes avoid the negative impact of energy deficiency on performance, and the correct construction of the training process with the maintenance of adequate energy consumption will have a positive impact on the performance and recovery processes after intensive physical exertion.

[Accordance of energy intake to energy expenditure in skiers across the preparation phase].

In elite sport the amount of physical activity requires a professional athlete to have a stable energy balance when the energy intake (EI) is equal to energy expenditure (EE). Its maintenance provides high performance across the phases of the training cycle. The purpose of this research was to analyze the compliance of EI to EE among skiers during the preparation phase of the training cycle. Material and methods. The single-centre, prospective, longitudinal, full-design, noncontrolled study has been performed on 55 highly trained cross-country skiers (mean age 20.1±4.7 years) during the preparation phase of the training cycle. EI was estimated by a 24-hour dietary recall. EE was estimated at rest and during physical activity by indirect calorimetry using the Oxycon Pro system. Results. During the preparation phase dietary calorie intake in skiers (3191±961 kcal/ day), estimated excluding sports drink consumption during the training, was lower approximately by 40% than the reference norms for people engaged in intensive physical activity. At the same time, there was 1.3-fold excess of fats in the diet against the background of low consumption of carbohydrates. Our results showed that in 75% of athletes the measured rest energy expenditure (REE) was higher than the calculated REE by 20% and amounted to 2139±363 kcal/day. Total EE during the preparation phase, calculated by application of Physical Activity Level (PAL) coefficient equal 2.4 (according FAO/ WHO/UNU recommendations), was 5137±873 kcal/day (73.9±12.3 kcal/kg per day). In most cases registered total EE was more than 5000 kcal/day, in other words, total EE exceeded the energy value of the daily diet and thus required the increase of EI. In addition, in our study we observed an increase of carbohydrate contribution to the total EE during high-intensity exercise. Conclusion. The discrepancy between dietary calories and daily EE among the elite athletes was revealed. An imbalance between carbohydrates and fats was identified in the diet, and that did not provide the optimal expenses of macronutrients during highintensity exercise.