Molecular genetic methods are an integral part of recent medicine. Polymerase chain reaction, Sanger sequencing, next-generation sequencing are widely used in many areas: diagnostics of infectious, inherited, oncological diseases, prenatal screening, study of polymorphisms that increase the risk of developing multifactorial diseases or promoting development physical qualities necessary to achieve success in sports and competitive activity. The growing demand for genotyping raises a number of ethical and social issues affecting the degree of usefulness of genotyping a healthy person and the scientific reliability of the data obtained using direct-to-consumer genetic testing.

The review presents and systematizes the laboratory diagnostic methods used today to study nucleic acids that carry important information about human health and physical qualities.

Long QT syndrome (LQTS) is a common disorder that leads to dramatic patient outcomes, chief among which is sudden cardiac death. This review provides detailed data on the diagnosis, prevalence, classification, etiology. The variety of causes leading to LQTS creates difficulties in the differential diagnosis of this condition and, as a result, LQTS often remains outside the attention of physicians who monitor the health of athletes. Particular attention is paid to the acquired forms of LQTS, particularly, the drug-induced form. The results of studies aimed at studying the prevalence of LQTS and the effect of drugs on the QT interval are presented. The influence of non-steroidal anti-inflammatory drugs on the QT interval is discussed in detail because they are often used by athletes. The purpose of this review is to expand understanding of the etiology of LQTS and justify the need for careful ECG screening and pharmacological monitoring in athletes.

The results of the analysis of red blood parameters in professional rowers showed that they have different mechanisms for the development of pre- and anemic conditions. This makes it necessary in each specific case to determine the prevailing of them, which requires an expansion of the set of recorded parameters.

The purpose of the study is to determine the effectiveness of the specialized product Fit Tonus for correcting the psychophysiological state and neuromuscular transmission in highly qualified athletes.

Materials and methods: the objects of research were: specialized product of sports nutrition for correcting the psychophysiological state and neuromuscular transmission Fit Tonus; 21 male martial arts athletes aged 14 to 25 years. The researches were carried out in accordance with official and conventional techniques. Body temperature, breathing rate, blood pressure level, heart rate was determined, heart rate variability, ECG, external breathing, O2 intake, total urine test, clinical blood test, biochemical blood indices were evaluated, water sectors of the body, body skinny weight, body fat weight were determined. Full-function cardiopulmonary analysis was performed using the Meta Lyzer 3B inpatient cardio-respiratory loading diagnostic system (Cortex Medical, Germany). Maximum oxygen consumption was determined by a Cosomed metabolograph (Italy). Biochemical parameters (bilirubin, ACT, ALT, urea, uric acid, glucose, cholesterol, HGT, amylase, alkaline phosphatase, creatinine) were examined on a Humalyzer biochemical analyzer. Water sectors of the body, the value of skinny body weight and fat body weight were determined on an analyzer for assessing the balance of water sectors of the body (Medass, Russia).

Results: in the analysis of biochemical blood values, the blood levels of indicator enzymes and their isoforms were normalized in a short time, despite high training loads. This fact reflects the adaptation of the athlete’s body to high-intensity physical activity when taking the Fit Tone product. The obtained results of the increase in GUS, FFV and Tiffno test indicate an increase in both functional capabilities and functional abilities of the external breathing system, as well as an increase in the efficiency of the respiratory center in athletes who received the tested product. The effectiveness of the test product is confirmed by the results of dynamic and stress samples in a stabilometric study. Results of examination of psychophysical status of single wrestlers showed that during usage of developed product such indicators as performance, vegetative coefficient, dynamism, speed of movement, accuracy of actions, stability of actions are significantly increased. At the same time, the level of fatigue and anxiety is reliably reduced.

Conclusions: the results of the researches performed showed that the product developed demonstrated efficacy for most of the parameters under research in the main group compared to the control (placebo).

It is known that a balanced diet and the intake of specialized foods that combine various types of proteins play a key role in expanding the adaptive potential of athletes and affect the effectiveness of the training process. In recent decades, various biomedical and technological strategies have been implemented in the development of specialized food products, including those for the nutrition of athletes. Proteins of milk and whey occupy an important place among the functional ingredients. Despite the fact that the average per capita consumption of protein in the structure of the diet in the Russian Federation over the past few years has been at a satisfactory level (in 2019 — 80.4 g/day, in 2020 — 81.4 g/day), for athletes with high body weight and extremely high energy consumption (4000 kcal/day and above), these values will be insufficient. In connection with this, special attention should be paid to various protein fractions in the development of SPP at a consumption level of at least 1.2 g/kg of the athlete’s body weight daily to ensure plastic and other functions in the body, physical performance and endurance.

Glutamine (GLN) and glutamic acid (GLA) are involved in many metabolic processes, from nucleotide synthesis to nerve impulse conduction; GLN is also an energy substrate for immunocompetent cells, making it an important link in the immune response. In stressful situations, which include significant physical activity, plasma levels of GLN and GLA decrease as a result of the amino acid being actively consumed in many biochemical reactions. GLN deficiency can lead to a number of negative manifestations in athletes and adversely affect athletic performance. The purpose of this work was to study the effects of glutamine deficiency and the possible replenishment of the deficiency by the consumption of exogenous forms of the substance when using glutamine-containing products; special attention was paid to the study of transient decrease in immune function as a relevant factor that impairs the mode of sports training.

Sport nutrition used to reduce weight or improve performance may contain psychostimulant aliphatic amines. The most common of them are DMAA, octodrine and AMP citrate. There are no toxicometric data for above compounds, which prevents their preclinical and clinical study and the formation of optimal dosing regimens or algorithms for overdose therapy. We determined that all of the above drugs have a low degree of cumulation of <20%. Based on the properties of this class of drug, the course should not exceed 7 days in order to avoid complications and the development of addiction.

Objective: to study the main indicators of free radical oxidation and antioxidant protection in the blood plasma of former athletes, depending on the period of cessation of sports.

Materials and methods: 24 former male athletes aged 19‒29 years were examined, who were divided into 2 groups of 12 people each (1st group — former athletes who stopped training for up to 2 years; 2nd — over 2 years). The control group consisted of 15 practically healthy untrained student volunteers of the same age. To study the state of free radical oxidation, we used the determination of the content of active products of thiobarbituric acid by reaction with thiobarbituric acid, spectrophotometrically at a wavelength of 535 nm. Determination of diene conjugates was carried out in the heptane phase after preliminary extraction with a heptane-isopropanol mixture at a wavelength of 233 nm.

Results: the direction of the shifts in the state of the oxidative balance was established depending on the period of detraining. The concentration of malondialdehyde in former athletes of the 1st group increased by 38.6 %. In the study of the content of diene conjugates, the staging of changes in the studied indicator was established with the maximum values in the former athletes of the 1st group and lower in the 2nd, exceeding the value of this indicator in the control group by 8.0 %.

Conclusions: the obtained data can be recommended for monitoring the state of athletes who stopped playing sports and taken into account when prescribing rehabilitation measures for the corresponding contingent.

The aim was to study the effect of normobaric hypoxia on biochemical parameters to assess homeostatic changes caused by mental work.

Materials and methods: 90 highly qualified athletes of various specializations took part in the scientific observation. Athletes performed psychophysiological tests to determine mental performance under normal conditions and under the influence of normobaric hypoxia.

Results: the concentrations of lactate (La), glucose (Glu), cholesterol (Chol), and triglycerides (Trigl) in the blood were measured four times at different stages.

Conclusions: it was shown that athletes after staying in NH conditions significantly increased the La, Glu, Chol and Trigl indices, which indicates the mobilization of energy resources and an increase in anaerobic processes in response to NH exposure. Re-performance of mental work after exposure to NH was associated with a marked decrease in the concentration of Glu, Chol, and Trigl, along with a slight increase in the concentration of La after normobaric hypoxic exposure, there are significant changes in the bioenergetic profile in athletes.

MicroRNAs are small non-coding single-stranded RNAs, 18 to 25 nucleotides long, they regulate gene expression at the post-transcriptional level through specific binding to the target mRNA, leading to its degradation. In recent decades, the development of technologies for determining the expression profiles of miRNAs has become an important part of research projects, and the role of miRNAs as potential highly informative molecular biomarkers of various physiological and pathological processes in the body is actively explored by the scientific community. In particular, physical activity is an important modifying factor for circulating miRNAs. Unlike classical blood biochemical parameters, which can change over time depending on the temperature and storage conditions of the sample, microRNAs remain stable during storage and even after multiple freeze-thaw cycles, which makes them an attractive and easily accessible target for detection. However, the determination of the microRNA expression profile in clinical practice is still difficult due to the high heterogeneity of analytical procedures used for testing. In sports medicine, the preanalytical stage is especially important, since often the conditions for sampling are not standardized and can affect the analysis result. This review shows the role of miRNAs as new sensitive biomarkers of the effectiveness of the training process and regulators of the body’s response to physical activity, and also discusses some preanalytical aspects of the analysis of miRNA expression profiles.