The study was conducted to evaluate the metabolic responses to a 24 h ultra-endurance race in male runners. Paired venous and capillary blood samples from 14 athletes (mean age 43.0 ± 10.8 years, body weight 64.3 ± 7.2 kg, VO_2max 57.8 ± 6.1 ml kg⁻¹ min⁻¹), taken 3 h before the run, after completing the marathon distance (42.195 km), after 12 h, and at the finish of the race, were analyzed for blood morphology, acid–base balance and electrolytes, lipid profile, interleukin-6 (IL-6), high-sensitivity C-reactive protein (hsCRP), and serum enzyme activities. Mean distance covered during the race was 168.5 ± 23.1 km (range 125.2–218.5 km). Prolonged ultra-endurance exercise triggered immune and inflammatory responses, as evidenced by a twofold increase in total leukocyte count with neutrophils and monocytes as main contributors, nearly 30-fold increase in serum IL-6 and over 20-fold rise in hsCRP. A progressive exponential increase in mean creatine kinase activity up to the level 70-fold higher than the respective pre-race value, a several fold rise in serum activities of aspartate aminotransferase and alanine aminotransferase, and a fairly stable serum γ-glutamyl transferase level, were indicative of muscle, but not of liver damage. With duration of exercise, there was a progressive development of hyperventilation-induced hypocapnic alkalosis, and a marked alteration in substrate utilization towards fat oxidation to maintain blood glucose homeostasis. The results of this study may imply that progressive decline in partial CO₂ pressure (hypocapnia) that develops during prolonged exercise may contribute to increased interleukin-6 production.

The aim of this study was to compare the motivations of successful marathon finishers (n=1,243) and inexperienced runners (control group, n=296). A total of 1,537 runners with 380 women (24.7%) and 1,157 men (75.3%) completed the Motivations of Marathoners Scales (MOMS) questionnaire, and the relationships between general motivation categories and selected demographic (e.g. gender, age, and education) and training characteristics were analyzed. Successful marathon finishers did not differ significantly in motivations from the control group (p > 0.05). Trivial to small correlations with age, educational level, and training characteristics were observed. Women marathon finishers exceeded men on the motivational scales for weight concern, affiliation, psychological coping, life meaning, and self-esteem and they scored lower on competitive motivation (p < 0.05). These findings confirmed that age and gender differentiate motivations in both successful marathon finishers and controls. There was also a significant relationship of some motivational aspects with level of education, experience and training frequency.

Vitamin D (25(OH)D) insufficiency and deficiency are highly prevalent in adult soccer players and can exceed 80% even in regions with high insolation; however, the treatment of this condition is often complicated. The aim of the present study was to examine the prevalence of vitamin D insufficiency and deficiency in youth Russian soccer players and the efficacy of its treatment. Participants were 131 young male football players (age 15.6 ± 2.4 years). Low vitamin D levels (below 30 ng/mL) were observed in 42.8% of the analyzed participants. These athletes were split in two groups composed of persons with vitamin D deficiency (serum vitamin D below 21 ng/mL) and insufficiency (serum vitamin D in range of 21–29 ng/mL). A dietary supplement of 5000 IU cholecalciferol per day was administered for two months. After the treatment, an average 92% increase in vitamin D concentration was observed (before treatment—19.7 ± 5.4 ng/mL, after treatment—34.7 ± 8.6 ng/mL, p < 0.001) and 74% of the post-treatment values were within the reference range (30–60 ng/mL). Serum concentration of vitamin D increased by 200% ± 98% (p < 0.001) during the first month of treatment with vitamin D deficiency and insufficiency being successfully treated in 83% of the football players. In summary, the prevalence of vitamin D insufficiency and deficiency was high in young Russian soccer players. Furthermore, it was indicated that the daily usage of cholecalciferol in a dose 5000 IU was an effective and well-tolerated treatment for vitamin D insufficiency. No linear dependency between the duration of treatment and increase in vitamin 25(OH)D concentration was observed.

There is now compelling evidence of the effectiveness of a range of post-exercise recovery techniques, including extended nights of sleep, cold water immersion, massage, and compression garments. Currently, limited information is available on post-exercise recovery methods used by elite endurance athletes. Therefore, this study investigated the actual methods of recovery used in this group of athletes. Google Forms were used to collect information on the recovery methods used by elite endurance track and field athletes (n = 153, 61.4% men, 38.6% women; average age: 22.7 ± 4.6 years). The most used methods of recovery were sauna bathing (96.7%), massage (86.9%), daytime nap (81.0%), and long night sleep (at least 9h) (61.4%). Recovery methods with proven effectiveness such as cold water immersion and compression garments were rarely used (15.0% and 7.8%, respectively). Overall, recovery methods were used more often when the tiers of the track and field athletes were higher. Massage and sauna bathing were the most used methods of post-exercise recovery among Russian endurance track and field athletes. In most cases, they were used in conjunction with short daytime nap and long night sleep. Higher tier athletes were more likely to use sauna bathing, massage, long night sleep, and daytime nap but not cold water immersion and compression garments as recovery methods; however, all these methods except for cold water immersion were widely used among elite-tier athletes.

The relative age effect (RAE) has been well studied in adolescent and adult soccer players; however, less information has been available about children engaged in regular soccer training and the role of performance. Thus, the aim of the present study was to examine the prevalence of RAE in children and adolescent soccer players, as well as the role of age and performance. Russian soccer players (n = 10,446) of various ages, playing positions and performance levels were examined for their date of birth. It was observed that RAE was widespread in Russian soccer teams of all age groups. RAE was most pronounced in children teams of the top tier Russian soccer academies and junior Russia national teams, where the proportions of soccer players born in the first quarter were 43.9% and 39.8%, respectively, whereas those born in the fourth quarter of the year were 7.7% and 6.3%, respectively. In top tier soccer academies, RAE did not vary by age group. In the middle tier soccer academies, RAE was less pronounced. It was still prevalent in the junior teams of the top tier clubs of the Russian Premier League, where 14.3% of the soccer players were born in the fourth quarter of the year compared to 42.9% born in the first quarter of the year. RAE can be observed in the top tier Russian adult teams as well, although it is less pronounced there. In summary, RAE is highly prevalent in Russian children and junior soccer and is associated with the level of competitiveness. At the same time, the proportion of players born in the fourth quarter of the year is higher in adult teams than in junior and youth teams, which is most likely due to the wider selection of players, not limited by their age and place of residence. In junior teams, RAE results in a bias towards selection of players who are more physically mature, whereas children who may be more talented but are less developed due to their younger chronological age tend to be overlooked.