Manifestation of the effect of relative age in cross-country skiing depending on the age and qualifications of athletes

Relevance . The relative age effect is widespread in sports, it affects selection, training conditions, the final composition of sports teams and motivation of athletes, and, ultimately, career. The aim was to assess the influence of the relative age effect in Russian cross-country skiing. Methods and organization of the study . The athletes' dates of birth were downloaded from the official website of the Russian Cross-Country Skiing Federation (RCCF), and the final season ratings by age groups were downloaded from the same website. Two approaches were used - counting the dates of birth of athletes included in each quarter of the year and identifying statistically significant differences between their numbers in 4 quarters. The second approach is calculating the Poisson regression indicators and determining the discrimination index of athletes who were born at the end of the year compared to those born at the beginning of the year. Two samples were used: athletes included in the FLGR ranking based on the results of the 2023/24 season (881 athletes) and skiers aged 17 to 30 years (born in 1994 and younger) included in the athlete database of the official FLGR website, a total of 13,671 athletes. The samples were divided into groups of 17-18, 19-20, 21-23 years old and adult skiers (24 years and older) of male and female gender. Data collection and statistical processing were performed in the RStudio program. Results. The effect of relative age was revealed in the sample of athletes included in the database of the official FLGR website in all age groups for men and in the group of female athletes over 24 years old. In the samples of qualified skiers (included in the FLGR rating), the effect of relative age was revealed only in the age group of 17-19 years for men.