An athlete of each kind of sport has a certain type of external body composition peculiar only to him, his somatic type. The physique and the state of the musculoskeletal system are important criteria for sports orientation and sports selection. The assessment of body types and its component composition is also one of the defining criteria for the selection and orientation of highly qualified skiers aimed at achieving success in competitive activities. The purpose of the study: using the method of three-level variation, to establish the features of the model parameters of the body of highly skilled cross-country skiers and assess the degree of their biological maturity. 19 masters of sports of Russia in highly qualified skiing, male and female, took part in the survey. In the course of the study, the anthropometric method was used, the body types of athletes were determined using the method of Dorokhov, which made it possible to reveal their morphological status and body composition. Analysis of the total body dimensions revealed that the average body length of male skiers was 177±2,3 cm, body weight - 72,7±2,15 kg, for female skiers -162,4±2,4 cm and 60,4±3,2 kg, respectively, which is consistent with the results reported in the literature. Variants of the biological development of the subjects are highlighted. An analysis of the studies carried out made it possible to state that cross-country skiers, on average, reach biological maturity by the age of 22. Bioimpedancemetry showed the symmetry of various parts of the body and its influence on the performance of basic motor actions. A high positive relationship between total body sizes and an inverse relationship between its fat and muscle components was established. Characterization of body types revealed the predominant distribution of body components in the zone of micro-mesosomal variation. The assessment of body types of athletes confirms the opinion of experts that weight loss increases the speed abilities of an athlete and reflects the direction of the training process. The developed evaluation coefficients, somatic types and variants of biological development will make it possible to select young athletes for cross-country skiing.

Background. Individual anatomical variability in the human body shape can be characterized by its proportions, which serve as the main components of assessing the type of human constitution. Aim. Establish individual typological features of the age-related changes in the fat component of the examined children, adolescents and youth. Material and methods. 409 residents of the Smolensk region aged 420 years were examined: 212 males and 197 females. The cohort was divided according to the International Age Periodization 1965. Studies of the longitudinal-transverse type lasted for 10 years (20102020). The research methods included anthropometry, somatodiagnostics, determination of the biological development variant. To determine the fat component, the thickness of the skin-fat folds was measured, the calculation was made according to the formulas of Ya. Mateyko. The analyzed data had a normal distribution (ShapiroWilk test). The hypothesis of statistical significance of differences was tested using Student's t-test. Results. Assessment of age-related changes in the body fat component of the subjects showed its continuous increase from 4 to 20 years. In female subjects it was higher, the significance of differences was established from the age of 12 (p 0.05). The fat component had a high and moderate degree of correlation with body height and weight (r=0.5330.753 and r=0.5300.833), skin-fat folds (r=0.5010.941) and body circumference (r=0.5030.790). Significant differences were established between the extreme variants of biological development (isochronic approach) (t=2.3052.604; р 0.05). In the examined males, the difference was 1012%, females 2530%. Somatotypological assessment (isosome approach) showed significant differences (t=3.4626.781; p 0.001) in the severity of fat mass in the subjects of both sexes of macrosomal and microsomal types. Conclusion. The conducted studies have confirmed the presence of high individualization of the fat components growth processes of male and female subjects of various somatic types and biological development variants.