Religious fasting in the Holy Month of Ramadan is an important element of the Muslim culture during which no eating or drinking is permitted from dawn till dusk. A considerable number of Muslim soccer players abide by these restrictions, which may cause a negative impact on key running performance parameters during competitive matches. Alterations to diet and water intake during the Holy Month of Ramadan may affect various running performance parameters in elite Muslim professional adult soccer players. This study was conducted with two groups of soccer players from the Russian Premier League (RPL): The Exposure Group (EG) consisted of 13 Muslims age 24.0 ± 2.8 years abiding by religious fasting and the Control Group (CG) included 13 non-Muslim age 26.0 ± 4.4 years. Using the Instat system, the running performance of each player was controlled in both groups during matches from the RPL before and in the third week of Ramadan (a total of two matches for every player). None of the measured parameters demonstrated significant changes in any match. In conclusion, restrictions in diet and liquid intake during the Holy Month of Ramadan had no negative influence on the running performance of elite Muslim professional adult soccer players during daytime matches.

(1) The purpose of this study was to examine the prevalence of the relative age effect (RAE) in the best young (10 to 15 years old) track and field athletes. (2) Hypothesis: The prevalence of the RAE in the best young track and field athletes of both genders will be evident in all age groups from 10 to 15 years old, which may be associated with the significant relationship between biological maturity, chronological age, and the development of physical qualities. (3) Materials and methods: In total, 1778 athletes volunteered for this study. The sample was based on the results of the best young athletes who participated in the final tournaments of the national competition “Shipovka Yunykh”(“Running spikes for young athletes”), which have been held since 1981. The sample group consisted of male and female athletes classified into specific age groups: 10 to 11 years old (n = 579), 12 to 13 years old (n = 600), and 14 to 15 years old (n = 599). Analysis was performed using Jamovi 1.8.1. The Chi-square test was used to compare the RAE between different groups. (4) Results: A wide distribution of the RAE was revealed both in the general sample and in boys and girls. The percentage of “early-born” athletes was 37.6% while only 12.3% were “late-born” athletes. The difference in the severity of the RAE may reflect the small sample of athletes from the fourth quartile, which was significantly less than the sample of boys from the fourth quartile (p = 0.04, OR 1.68, 95% CI 1.02–2.78). The RAE was also evident in all age groups of boys and girls, without any statistically significant differences in the severity (p > 0.05, Chi = 2.135, V = 0.02). In the 14- to 15-year-old male athletes group, the number of early-born compared to late-born athletes peaked. The RAE was most common amongst the most successful track and field athletes. Among the competition medalists during the analyzed time period, more than 50% of athletes were born in the first quarter and no athletes were born in the fourth quarter.

Background The relative age effect (RAE) is most prevalent in highly competitive youth soccer and persists to a lesser extent in senior soccer. However, it is known that soccer players born in the second half of the year are as successful at senior level, indicating that they are equally talented although under-represented at youth level due to bias during the selection process, in which the emphasis is on more pronounced physical qualities in a specific period of time. Examining the prevalence of the RAE among professional soccer players depending on the level of competition and playing position, as well as analyzing the relationship between the player’s birth quarter and market value, are of scientific interest. Methods The dates of birth, playing position, and market value of all adult male soccer players included in the final rosters of teams from the top-division of 54 European countries, listed on www.transfermarkt.com on August 15th, 2020, were analyzed (18,429 soccer players in total). All players were categorized into four groups according to the quarter of birth (Q) and playing position. All teams were further sub-divided in groups depending on the soccer clubs’ level of representation in the UEFA Champions League. Results Of 18,429 players, 30.9% were born in Q1, 25.7% in Q2, 23.8% in Q3 and 19.6% in Q4. The number of soccer players born in Q1 was lower in less competitive leagues. The number of players born in Q1 decreased as the level of competition decreased; the highest percentage of these players was observed in clubs that are among the top 50 ranked in UEFA or compete in the most prestigious European championships. The RAE was less pronounced in teams that participate in lower competitive championships. There was no significant difference in market value between players playing position and level of competition when born in different quarters. Although, the most expensive soccer players in the European championships were late-born forwards. Players of various groups differed in their market value. Conclusions The RAE is currently prevalent in all the most competitive senior soccer leagues and teams in Europe regardless of playing position. There are no significant differences in market value between players of the same playing position and level of competition when born in different quarters. The most expensive soccer players in the European championships are forwards born in Q4. These findings may indicate that the under-representation of “late-born” soccer players in youth, and then consequently in adult soccer, is not associated with lower talent, but with other factors, possibly based on physiological characteristics and socio-cultural factors. Further measures are needed to mitigate the discriminatory effects of selection bias based on the RAE.

BackgroundXenon and argon inhalation were included in the WADA Prohibited List in 2014 due to the reported positive effects on erythropoiesis. There has also been suggestions that steroidogenesis stimulation occurs as a result of the use of these substances. Currently, Xenon is on the WADA Prohibited List notable affecting erythropoiesis as a Hypoxia-inducible factor (HIF) activating agent. Thus, the systematic review of studies supporting these notions is of great interest.MethodsA thorough search for articles on the effects of Xenon and argon inhalation on erythropoiesis and steroidogenesis, as well as their negative effects on human health and methods of their detection in body fluids was conducted. Pubmed and Google Scholar databases were researched, as well as the special research section of the WADA website. The search was conducted in accordance with PRISMA guidelines. All articles in English published between 2000 and 2021 were analyzed, as well as reference studies meeting the search criteria.ResultsOnly two publications in healthy human subjects evaluating the effects of Xenon inhalation on erythropoiesis were found with no conclusive evidence of a positive effect on erythropoiesis. Both articles were published after 2014 when the gases were included on the WADA Prohibited List. Three more studies were conducted in animal models and one further study was conducted with human patients who had undergone Xenon anesthesia. There were no studies on the effect of argon inhalation on erythropoiesis. No studies were found on the effect of Xenon or argon inhalation on steroidogenesis in healthy subjects. No studies related to the effects of Xenon or argon inhalation on erythropoiesis and steroidogenesis were found on the WADA website.ConclusionThere is still inconclusive evidence to support the administration of Xenon and argon inhalations on erythropoiesis and steroidogenesis and their positive effects on health. Further research is needed to establish the effects of these gases. Additionally, improved communication between the anti-doping authorities and all key stakeholders is required to support the inclusion of various substances on the Prohibited List.

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