Aim: study the dynamics of osteogenesis and bone resorption markers in elite biathlonists owing to the “compression” specifics of cyclic training aids, mainly used at the stages of the early season of the annual training cycle.
Materials and methods: 23 elite biathlonists undergoing centralized training as the members of the Russian national team took part in the study.
Results: no changes in the P1NP amounts reaching a reliable level were recorded throughout the early season. The average group osteocalcin amount at the precompetition stage significantly (p < 0,05) increased compared with that measured at the special preliminary stage. Dynamics of β-CrossLaps concentration showed significant (p < 0,05) decrease during the transition from the general preliminary to the special preliminary stage.
Conclusion: the degree of intense training activity influence on the activity of bone cells and in turn the response of bone tissue to training loads depend on a set of exercise parameters performed by the athlete, such as duration, intensity, specificity, recovery time and mechanical stress. Optimizing the ratio of cyclic aids with different levels of compression loads during specialized training promotes adaptive changes which protect bone tissue from resorption affected by intense physical exercises. When analyzing the levels of bone metabolism markers for diagnosis and monitoring disorders associated with skeletal overload which could occur high-intensity training loads, an individual approach as well as recognition of the load specifics and parameters performed by an athlete at a specific stage of the training macrocycle are required.

The purpose of the study: the study of the characteristics of the intestinal microbiome in young men who are professionally engaged in sports.
Materials and methods: the study involved 36 young men aged 18 to 26 years. Fecal samples were taken from the study participants and then bacterial DNA was isolated from the obtained samples.
Results: comparing the intestinal microbe of athletes with the control group, it is possible to trace the positive effect of sports on the overall diversity of representatives of the intestinal microbiota. When analyzing the taxonomic composition, it is worth separately noting the increase in representatives of lactate-producing bacteria and the increased content of Akkermansia muciniphila in athletes.
Conclusions: the results of the study indicate the effects of sports training on the human gut microbiota and suggest the presence of a close two-way relationship “microbiome — muscle tissue”.

Aim: To investigate the relationship between sleep quality and sports performance of individuals with physical impairments in individual sports.
Methods: Three hundred and thirty-eight athletes (age: 36.43 ± 10.81 yrs.; 145 women and 193 men) participated in the study. Volunteers completed a five-part questionnaire on sleep quality. Based on the information available in the Provincial boards and the Veterans and Disabled Federation, the positions obtained by each athlete were considered as a criterion measure of sports performance.
Results: Result showed that in women the positions obtained at the Provincial, National and International level was significantly higher compared with male athletes (p < 0.05). There was no significant relationship between sleep quality and athletic performance of women, men and total (both men and women) athletes in individual sports at the Provincial level (women: r = 0.070, p = 0.409; men: r = -0.844, p = 0.242 and men and women: r = -0.029, p = 0.600); National level (women: r = 0.093, p = 0.271; men: r = 0.020, p = 0.785, men and women: r = 0.039, p = 0.474) and International level (women: r = 0.024, p = 0.781; men: r = 0.094, p = 0.191, men and women: r -0.078, p = 0.151).
Conclusion: There was no significant difference in sleep quality between male and female athletes with physical impairments. No significant relationship was observed between athletic performance and sleep quality between the two groups. In future research, field studies can be used to evaluate this relationship.

Objective: evaluation of the feasibility of using the Borg CR10 perceived exertion scale in the training process of young football players and its role in injury prevention.

Material and methods: 48 athletes aged 15–17 were examined by scale of perceived exertion during the 7 month every day within 20 minutes after the training. The coaches also assessed the degree of perceived exertion. A comparative retrospective analysis of injuries was done for the periods of the mycrocycle of the youth football league of the seasons 2020–2021 and 2021–2022 based on muscle injuries, ligament and joint capsular injuries.

Results: Athletes’ scores on the Borg CR10 scale in the preparation, competition and transitional stages of the competitive macrocycle are 5.08 ± 1.28, 5.00 ± 1.16 and 4.67 ± 1.38, respectively. The coaches’ scores for the aforementioned periods are 4.78 ± 0.89, 5.09 ± 1.05 and 4.82 ± 0.99. The total scores of players and coaches is 5.20 ± 1.85 and 4.96 ± 1 respectively. Moreover, there is no statistically significant difference between the rate of perceived exertion between players and coaches for the whole season (p = 0.288).

There is a decreased injury rate in young professional athletes group when the Borg CR10 scale of perceived exertion is measured in a season with the use of this scale compared to a season where the Borg CR 10 scale was not used (p = 0,028).

Conclusion: the Borg СR10 scale is a useful methodology for assessing the level of perceived exertion of a young athlete and can be used for early training corrections in order to reduce injuries.

Purpose: Studying the effect of the Uddiyana Bandha (UB) yoga breathing exercise on blood flow in the marginal sinus (MS).
Materials and methods: The study involved 16 people in whom blood flow in the MS was assessed against the background of free breathing, during voluntary expiratory apnea (VEA) — 5 seconds, and during UB — 5 seconds. The maximum blood flow velocity (Vmax), the time-averaged maximum velocity Vmean, and the index phase character (IP) were recorded.
Results: When recording Vmax during VEA (stage 2) for 5 seconds, it did not show significant differences compared to free breathing (stage 1); within 5 seconds of execution, the UB (stage 3) was significantly higher than the baseline (stage 1), p < 0.001, and also higher than the VEA (stage 2), p < 0.001. Vmean PEA (stage 2) for 5 seconds was without significant differences compared to free breathing (stage 1). During 5 seconds of UB execution (stage 3), Vmean was higher than the baseline (stage 1), p < 0.001, and also higher than VEA (stage 2), p < 0.009. Against the background of free breathing (stage 1) and PEA (stage 2), the values of IP and were without significant differences compared to UB (stage 3).
Conclusions: The UB breathing exercise increases the maximum linear blood flow velocity Vmax and the time-averaged maximum blood flow velocity Vmean in the MS, which may indicate activation of cerebral venous outflow during the exercise.

Objective: to consider, based on the analysis of domestic and foreign sources, the main issues of epidemiology, pathogenesis, diagnosis, and treatment of plantar fasciitis in athletes.
Materials and methods: an analysis of data from electronic portals such as PubMed-NCBI, Scopus, Google Scholar, Cochrane Library, and “Scientific Electronic Library eLIBRARY.RU” was conducted by request: “plantar fasciitis sport”, “plantar fasciitis in athletes”, “plantar fasciitis physical therapy”. The review analyzed 103 publications, of which 16 are devoted to the problems of plantar fasciitis in sports; 34 meta-analyses, 39 reviews, 11 randomized clinical trials and 19 other studies based on the principles of good clinical practice were included.
Results: the prevalence of plantar fasciitis among athletes was evaluated, ranging from 5.2 to 17.5%. It has been demonstrated that the leading morphological change is the degeneration of connective tissue, which, in combination with repetitive microtrauma, can cause pain. In athletes, plantar fasciitis is often accompanied by various biomechanical disorders and is frequently associated with flat feet. It has been noted that ultrasound and magnetic resonance imaging, which allow for the detection of thickening of the plantar fascia and signs of its degenerative changes, as well as X-ray examination of the feet, are considered as additional diagnostic tools. A wide range of approaches to the treatment of plantar fasciitis has been described: pharmacological methods of intervention, physical and rehabilitation medicine, as well as surgical intervention, which have varying degrees of proven efficacy.
Conclusion: since plantar fasciitis in athletes is characterized by a high prevalence and resistance to ongoing therapeutic measures, which is reflected in limited studies, the development of pathogenic justified measures for timely diagnosis and treatment of this condition, primarily focusing on biomechanics, will contribute to the athlete’s prompt resumption of full training and competitive activities. Directions for further research on the issue of foot pain occurrence in athletes have been proposed.

Purpose: to analyze literature data on the influence of some components of specialized food products for athletes on the qualitative and quantitative composition of the intestinal microbiome and related indicators of the macroorganism.
Materials and methods: The selection of current scientific articles was carried out in open electronic databases: Web of Science, Scopus, PubMed. ncbi, Scientific Electronic Library of the Russian Federation (elibrary.ru), Russian State Library and others. The search depth is not limited.
Results. It has been shown that normalization of the diet, and therefore the nutritional status, deficient in some macro- (calcium, magnesium), microelements (iron, zinc), vitamins (A, B1, B2, B6, folates, B12, D), antioxidants, is possible not only with the help of dietary supplements containing these and other (L-carnitine, caffeine) substances, but to a significant extent this improvement is possible through the consumption of pro- and prebiotics, modulating and creating favorable conditions for maintaining the optimal composition of the intestinal microbiota and endogenous synthesis of various biologically active substances. The participation of microflora in maintaining the integrity of the functional activity of the gastrointestinal tract, ensuring an adequate immune response, maintaining acid-base balance and water-salt metabolism, and the synthesis of a number of biologically active substances has been established. Most studies have been conducted on animals.
Conclusion: optimization of athletes’ diets using specialized food products that have a modulating effect on microflora plays an important role in maintaining health and performance. The issue requires further study with the participation of volunteers.