Aim: to study the quality of sleep and the relationship between sleep disorders and injury among young elite soccer players.

Methods: the study summarizes data from relevant questionnaires obtained through anonymous cohort testing of 236 male football players from leading football academies, two farm teams of leading Russian Premier League clubs and three national youth teams.

Results: the average sleep duration in the study participants was 9 hours. The prevalence of sleep disorders was 7 % (PSQI, Pittsburgh Sleep Quality Index) and 10 % (ASBQ, Athlete Sleep Behavior Questionnaire) and among the youngest soccer players, this prevalence of violations was the lowest. Significant or moderate daytime sleepiness was found in 59 % of participants. The risk of serious disorders increased with age. Sleep disorders significantly affected injuries according to the results of the PSQI questionnaire and retrospective collection of information about injuries.

Conclusion: the confirmed relationship between injuries and sleep disorders allows us to consider sleep quality improvement as an important component of injury and morbidity prevention among athletes of team sports.

Purpose of the study: to assess risk factors for the development of nonspecific back pain syndrome in skydivers.

Materials and methods: A single-center, prospective, non-randomized study included 173 men aged 25 to 55 years who had been followed up with low back pain for 1 to 5 years. The main group included 89 people involved in parachuting (experience from 5 to 20 years, number of jumps — 276 (167; 387) times), the comparison group — 84 patients who had never jumped with a parachute. Depending on the total number of jumps, the main group was divided into 2 subgroups: less than 198 (n = 29) and more than 198 parachute jumps (n = 60). All patients underwent clinical neurological examination and magnetic resonance imaging (MRI) of the spine. MRI was used to quantify the presence of disc tissue displacements, the presence of straightening lordosis, and spondylolisthesis. Statistical processing of the obtained data was carried out using the IBM SPSS Statistics 25 program.

Results: a correlation was established between the appearance of disc tissue displacement in the spine according to MRI and the number of parachute jumps in the main group (r = 0.430; p < 0.001). The indicated pathological changes in the spine in paratroopers occurred when the total number of jumps was 198 or more. Among parachutists of the main group, displacement of disc tissue in the spine correlated with the level of pain intensity (r = 0.337; p < 0.001) and the degree of functional impairment according to the results of the questionnaires Oswestry (r = 0.325; p < 0.001) and Roland Morris (r = 0.292; p < 0.001). The highest rate of pain syndrome and degree of disability was in the subgroup of paratroopers with extensive experience (p < 0.05), while other groups of patients had no differences in this indicator.

Conclusions: in skydiving athletes, the intensity of pain in the lower back and the degree of degenerative-dystrophic changes depended on the number of parachute jumps.

Objective: to estimate the functional features of the cardiorespiratory system of female cross-country skiers with different skills levels at the maximal bicycle ergometer test.

Material and methods: 70 female cross-country skiers were divided into three groups. The first group included 21 cross-country skiers with first adult sporting rank, the second — 25 candidates in master of sports, the third group — 24 sport masters in cross-country skiing. Maximal exercise tests were used to determine cardiorespiratory fitness via spiroergometric system «Oxycon Pro» (Jaeger, Hoechberg, Germany).

Results: The most notable differences were observed between the first-class and the masters of the sports groups. In the first-class group the heart rate during the maximal exercise test was, on average, 11 beats/min higher than in the master of sports group (p<0.05), and the oxygen consumption at the anaerobic threshold was, on average, lower by 7.7 ml/min/kg (p < 0.05) when comparing the same groups.

Conclusion: The influence of skills levels on physiological parameters at maximal bicycle ergometer test was shown. The capacity in the first group occurs due to cardiovascular system tension, and the same in the group high qualification skiers happen due to the mechanisms of oxygen transport development.

Purpose of the study: to evaluate the “lipid peroxidation-antioxidant protection” system in freestyle wrestlers under the influence of intense physical activity in order to identify the nature of oxidative processes and the antioxidant status of the athletes’ body.

Materials and methods: the study involved athletes — freestyle wrestlers, boys 18–22 years old, with sports qualifications: candidate master of sports or master of sports, regularly involved in freestyle wrestling. The control group consisted of students who did not have a sports category and were not involved in sports activities, comparable in gender, age, weight category with the comparison group.  The material for the study was plasma and red blood cells. Blood sampling from athletes was carried out twice, at the end of the preparatory and competitive periods, in the morning, on an empty stomach from the ulnar vein, in accordance with generally accepted requirements. Components of lipid peroxidation and antioxidant defense were determined using spectrophotometric and fluorometric methods.

Results: it was found that in athletes after intense physical activity (competitive period), there is a significantly significant decrease in substrates with double bonds by 61 %, primary products by 59 % and intermediate products by 44 %, an increase in the final products of lipid peroxidation by 25 % against the background of inhibition activity of antioxidant protection components: retinol by 40 %, superoxide dismutase by 7 % and reduced glutathione by 11 %.

Conclusion: The level of free radical processes increases during physical activity due to the accumulation of oxygen in organs and tissues, and depends on the intensity and duration of the exercise. In the course of the study, it was established that the preparatory and competitive periods, in comparison with the control group, among freestyle wrestlers, depending on the previous level of physical activity, are characterized by activation of lipid peroxidation processes and inhibition of enzymatic and non-enzymatic components of antioxidant protection. The established changes are recommended to be taken into account when conducting comprehensive rehabilitation of athletes, when developing recommendations for improving the training process, as well as when using antioxidant complexes for athletes aimed at restoring various parts of the body’s antioxidant defense.  

Objective: to compare the results of endurance, strength and functional status of spine stabilisers muscles (core stability) obtained by testing national teams athletes of different sports.

Materials and methods: 71 male athletes (judokas, boxers, cyclists and wrestlers) aged 18–25 years participated in this study. Athletes were asked to perform «Motor Control test» in static and dynamic mode and three trial attempts were given to be familiar with test.

Results: cyclists were found to have the highest overall scores in both static and dynamic modes, but the results for different spatial parameters differ. Statistically significant differences were found when comparing the following core stability indicators: «Forward (static mode)», «Back (dynamic mode)», «Left (static mode)», «Forward-left (static mode), «Forward-right (dynamic mode)», «Back-left (static mode)», «Back-left (dynamic mode)», «Back-right (dynamic mode)».

Conclusion. The cycling requires more core stability than boxing, wrestling and judo, but further investigations and larger samples of athletes are needed.

The presence of weight categories in martial arts requires an athlete to constantly maintain and control body weight and, in some cases, to reduce it. For this reason, it is common among martial artists to use forced methods of body weight reduction, which are often unphysiological and may have a negative impact on performance, as well as pose a danger to health. In this connection, it is of practical interest to search, analyse and introduce into practice physiological and safe methods of body weight reduction by athletes-athletes before participation in competitions. The aim of the study is to evaluate the safety and effectiveness of various methods of weight loss in athletes preparing to participate in competitions.

Materials and methods: the review was conducted according to the methodology of Scoping review. Articles were selected in the domestic data-bases eLibrary and Russian State Library, using the following keywords: «методы снижения массы тела ИЛИ снижение массы тела ИЛИ весогонка» И «единоборства ИЛИ боевые виды спорта», as well as in the foreign databases ScienceDirect and PubMed, using the following keywords: «making weight OR weight loss» AND «combat sports», placed in a search depth of 15 years.

Results: we found 121 studies, 3 duplicates were excluded after initial screening, 118 studies were screened for inclusion criteria, and a total of 16 studies were included in the review.

Conclusion: a reduction of 5 to 10 % of body weight less than 7 days before the official weigh-in may adversely affect performance parameters and the state of the body’s functional systems. A reduction of up to 5 % of body weight 7 or more days before the official weigh-in is the safest.

Aim: To determine the most effective dose of the box jump exercise for increasing explosive leg muscle strength in adolescents, as measured by vertical jump height.

Methods: This study is a field experimental study using a randomized control group pretest-posttest design by providing different doses of jump-to-box exercise. The experiment was conducted on Buqa’tum Mubarakah Junior High School students in Makassar, Indonesia, on February 16 to August 16, 2022 and obtained a total sample size of 60 male subjects aged 15-16 years. The participants were randomly divided into four experimental groups, each consisting of 15 people who were given jump-to-box exercises with different doses.

Results: The results of the ANOVA test analysis showed that training with a loading dose of 24 cm and 5 minutes duration had a significant effect on increasing leg muscle explosive power with a p-value = 0.005. The other three groups did not show statistically significant improvements in jump height.

Conclusion: The jump-to-box exercise with the box height of 24 cm and training duration of 5 minutes resulted in the highest average vertical jumping ability compared to other dose groups. This exercise protocol has an optimal effect on vertical jumping ability and limb explosive power in adolescents compared to other protocols.

Objective: to substantiate the expediency of including training walking in an exoskeleton in the complex rehabilitation of patients with severe motor dysfunctions of the lower limbs due to spinal cord injury (SCI).

Methods: 120 patients (84 men and 36 women, age 37.1 ± 8.40 years) with the consequences of SCI at the level of thoracic and lumbar spine who were in the hospital at the second stage of medical rehabilitation were examined. The duration of injury ranged from 1 year to 19 years (77.8 ± 4.05 months). All patients were divided into two groups (80 and 40 patients), comparable by sex, age, duration and severity of injury. Training walking in exoskeleton have been added in the group I rehabilitation program. ASIA, SCIM III scales and SF-36 quality of life questionnaire were used to evaluate the effectiveness of the rehabilitation measures.

Results: there was an increase in the total score on SCIM III by 3.20 ± 0.50 (p = 0.05) in group I, which indicates an increase in the level of functioning and daily activity of patients. Positive dynamics was revealed when assessing the quality of life using SF-36 questionnaire: sum index reflecting the psychological component of health increased from 56,0 to 59,5 points (p = 0,05). Group II also showed positive dynamics of the analyzed indicators, but the changes by the end of the rehabilitation course were not statistically significant.

Conclusion: the use of exoskeleton training walking at the second stage of medical rehabilitation increases the effectiveness of rehabilitation measures and improves the quality of life of patients with severe motor dysfunctions of the lower limbs due to spinal cord injury (SCI).

Objective: to assess the effect of voluntary hypoventilation during yoga breathing exercises on gas exchange and EEG activity in a group of healthy, trained practitioners.

Materials and methods: 25 volunteers (21 men and 4 women, average age 42.96 ± 9.19 years) performed hypoventilation yoga exercises with a decrease in respiratory rate to 1–1.5 times/minute. Registration of respiratory rate, tidal volume and minute volume of breathing, gas analysis of exhaled air (PetCO₂, FeO₂) and spectral analysis of electroencephalogram (EEG) in gICA model were carried out during breathing with a frequency of 1–1.5 times/minute and during relatively free breathing with mental calculation.

Results: Breathing with a frequency of 1–1.5 times/minute causes a decrease in minute volume of breathing, the development of alveolar hypoxia and hypercapnia, which leads to an increase in the power of some local components in the slow delta, theta and alpha EEG bands. In addition, breathing with a frequency of 1–1.5 times/minute is accompanied by a decrease in the alpha- and beta-power of some components, the sources of which are located in the motor areas of the cortex, but is also accompanied by an increase in the power of components with widespread scalp topography in beta and gamma bands.

Conclusion: Voluntary hypoventilation during yoga breathing exercises leads to the development of alveolar hypoxia and hypercapnia, accompanied by an increase in the power of local components in the slow EEG bands. At the same time, the alpha and beta powers of components localized in the motor areas of the cortex decrease, which may be a consequence of muscle tension during slow breathing.

Aim: to identificate the diagnostically significant signs of connective tissue dysplasia, detection of which will allow adequate sports activity selection, injury prevention and effective rehabilitation.

Materials and methods: clinical-somatometric examination of 117 persons aged 18 to 49 years (35.14 ± 5.63 years) with recurrent musculoskeletal injuries occurred during habitual physical training was carried out. Corresponding subgroups were formed by age and gender. Ranked by significance clinic-morphological dysplastic features, identified by T.I. Kadurina and L.N. Abbakumova (2008), were used to assess the mesenchymal tissue state. The control group, comparable to the main group by age and sex, was represented by 36 healthy young people.

Results: persons with a predisposition to musculoskeletal injuries have a high dysplastic sign incidence. It was proved that clinically significant of them are moderate to high degree myopia, gothic palate, excessively soft auricles, “crunch” during movements in the temporomandibular joint, pathological spine kyphosis, joint hypermobility, chest deformities, O- and X-shaped legs and varicose lower limbs. Clinically significant markers of connective tissue dysplasia were found to be modified with age and to have characteristic gender features.

Conclusions: the study results have particular importance for injury-free physical activity and medical-biological support for sports activities.