Endurance Coefficient Research Articles

Вплив засобів фізичної терапії на показники діяльності серцево-судинної системи, метаболізму та психоемоційного статусу осіб похилого віку з метаболічним синдромом та старечою астенією

An increase in the prevalence of insulin resistance in the elderly, associated with physiological changes in carbohydrate metabolism during the aging process, is associated with a high risk of cardiovascular accidents and endocrine diseases. This problem requires a solution by healthcare professionals with medication and non-medication. The purpose of the study was to determine the effectiveness of the program of physical therapy by the dynamics of indicators of the cardiovascular system, carbohydrate and lipid metabolism, psychoemotional status of elderly people with frailty and metabolic syndrome. Material and methods. 96 elderly people were examined. The control group consisted of persons without metabolic syndrome and without frailty. The main group 1 consisted of patients with metabolic syndrome and frailty with a low level of therapeutic alliance who did not want to cooperate with a physical therapist and / or actively improve their health on their own. The main group 2 included patients who agreed to undergo a developed program of physical therapy (a high level of therapeutic alliance) using kinesitherapy, massage, nutritional correction, education of the patient and his family, elements of cognitive training and occupational therapy for 1 year. The effectiveness of the program was assessed by the dynamics of systolic and diastolic blood pressure, heart rate, Kvass endurance coefficient, Baevsky's adaptive potential, Robinson's index, physical performance (based on the results of a 6-minute test), carbohydrate parameters (fasting blood glucose and after glucose load) and lipid (concentration of cholesterol, triglycerides, high density lipoproteins) metabolism, the level of depression according to the GDS-15 questionnaire. Results and discussion. In elderly people with frailty and metabolic syndrome, a statistically significant (p <0.05) deterioration in the parameters of the functioning of the cardiovascular system (according to the levels of DBP, heart rate at rest, Kvass endurance coefficient, Baevsky's adaptive potential, Robinson's index), physical performance (according to the results of a 6-minute test - distance, severity of fatigue, shortness of breath, cardialgia), biochemical parameters (fasting hyperglycemia, impaired glucose tolerance, atherogenic dyslipidemia), psycho-emotional state (depression) from their peers. The use of physical therapy tools led to a statistically significant improvement (p <0.05) of all the studied parameters of the functioning of the cardiovascular system, biochemical parameters in elderly people with metabolic syndrome and frailty, an increase in their physical performance, and an improvement in psycho-emotional status. A low level of therapeutic / rehabilitative alliance led to unsatisfactory fulfillment or non-fulfillment of the recommendations provided by patients and is associated with a lack of improvement in the state of the cardiovascular system, physical performance, age-associated depression. Conclusion. It is advisable to include physical therapy means in the rehabilitation programs for elderly patients with comorbid pathology like frailty and metabolic syndrome for the prevention of cardiovascular accidents

AGILITY AND SPEED RESISTANCE LEVEL STUDY OF HIGHLY QUALIFIED MID-RACE RUNNERS

The study of professional literature and information sources showed that the improvement of results in the mid-race running depends on the joint development of agility and speed endurance. A study of agility skills of high-class mid-race runners showed that they have a high level of agility, which has a high correlation percent value with an athletic result of 800 m: men - 94.9 %, women - 92.9 %. Thus their agility skills and speed endurance correspond to the principle offered to determining a speed endurance coefficient.

Understanding and predicting the DC voltage endurance coefficient of cross-linked polyethylene insulation under thermal ageing

Voltage endurance coefficient (VEC) is a parameter used in the design of withstand test and insulation thickness of cross-linked polyethylene (XLPE) cables. Thermal ageing is inevitable in operation of cable, but the thermal ageing effect on the VEC is rarely considered. In this study, the trend of VEC of XLPE films under DC voltage during thermal ageing is investigated by 120 and 135°C thermal ageing experiments. The results show that, after 14 days of 120 and 135°C thermal ageing, the VEC decreases from 20.74 to 7.05 and 3.93, respectively. To understand the effect of thermal ageing on the VEC, the VEC is described as a function of the free energy increment which is proportional to the degree of polymerisation (DP) and the electric field. A simulation calculating the free energy increment of several molecular chains is conducted to confirm the proportional relationship between the free energy increment and the DP, the electric field. Based on the function of the VEC, a predicting method for the VEC under thermal ageing is developed. The experimental results of 120 and 135°C thermal ageing are used to confirm the preciseness of the proposed predicting method.

Physiological substantiation for indicators application to evaluate the young students fitness health

To characterize fitness health, defined as the state of the physical well-being of the body, due to the functional state, physical qualities and component composition of the body, assessment methods are needed. The purpose of the study : physiological justification of the choice of indicators for assessing the fitness of students health. Methods: the study was conducted according to the results of preventive examinations of 303 students 18-24 years old at the Health Center, including: anthropometry, bio-impedance research and assessment of physical fitness. Results. To assess fitness health, we used an index of the component composition of the body, which characterizes the ratio of components (fat and active cell mass, water content and basic metabolism), which ensures the flow of metabolic processes, maintaining nutritional status, shaping the nature of working capacity and the adaptive potential of the body. The body composition index has the greatest correlation with the level of fitness health. Assessment of physical fitness, necessary when choosing an adequate regime of power and aerobic load, was carried out according to motor tests included in the RWD complex. Using the index method (power index, Skibinskaya index, endurance coefficient), the functional state of the basic life support systems of the body involved in the implementation of motor activity was characterized. Conclusions. The application of the studied indicators for assessing fitness health has a physiological justification and is confirmed by the correlation analysis.

Особенности анаэробной работоспособности биатлонистов в зависимости от типа вегетативной регуляции сердечного ритма

Successful work of biathletes on the track and at the shooting range largely depends on the typological features of the autonomic regulation of heart rate. We examined 46 biathletes aged 18–25 years. The types of autonomic heart rate regulation were determined according to the generally accepted method using Varikard 2.51 equipment. Sport-specific performance was measured on the Ergomedic 894E Peak Bike ergometer (Monark Exercise, Sweden). Personified types of autonomic heart rate regulation were combined into two groups: with the dominance of the central regulation mechanism (CRM, 45 % of subjects) and of the autonomic regulation mechanism (ARM, 55 % of subjects). The 6-second test for assessing speed abilities revealed statistically significant (p < 0.05) differences: biathletes with CRM were faster, their peak power output was higher and their time to reach maximum speed was shorter compared to biathletes with ARM. As to the strength abilities, subjects with CRM were superior (p < 0.05) to their colleagues in terms of speed and relative power output; their power gradient was greater, and their time to reach maximum speed was shorter (p < 0.05). During the 15-second test, biathletes with ARM showed a statistically significant (p < 0.05) increase in total work output, absolute power output, and endurance coefficient compared to the subjects with CRM. When switching to the 45-second mode, biathletes with ARM retained their advantages (p < 0.05) in terms of total work output, absolute power output, and speed endurance. At the same time, their relative power output was lower compared to that of athletes with CRM. Thus, with the shortest possible anaerobic mode, the efficiency is higher in biathletes with dominant CRM, while at longer modes, in biathletes with ARM predominance.

Критерії адекватності фізичних навантажень та їх використання у спорті, фізичному вихованні і фізичній реабілітації

Актуальність. Відомо, що фізичні навантаження (ФН) позитивно впливають на організм людини, яка за- ймається руховою активністю, чи пацієнта в процесі реабілітації лише тоді, коли вони є адекватні до функціональних можливостей. На сьогодні актуальною проблемою залишається дозування ФН і моніторинг процесу їх впливу на організм для підвищення рівня здоров’я людей у процесі фізичного виховання, спортивних занять та під час реабілітації хворих. Постала необхідність пошуку критеріїв адекватності ФН, за якими можна було б відслідковувати їх величину й ефективність. Мета статті – з’ясувати критерії адекватності ФН за показниками серцево-судинної системи (ССС) на моделі з граничними ФН. Методи досліджень. Досліджено реакцію на граничні ФН спортсменів високої (ВК) і низької кваліфікації (НК) для з’ясування маркерних показників ССС, за якими спортсмени ВК та НК відрізняються. Вивчено показники центральної гемодинаміки й варіабельності серцевого ритму, проведено статистичну обробку результатів, виявлено кореляційні зв’язки. Результати роботи. Установлено, що за зміною показників ЦГД: ЧСС, серцевого індексу (СІ), хвилинного об’єму крові (ХОК), показниками роботи (РЛШ) і потужності лівого шлуночка (W), швидкості вигнання крові (Ve), коефіцієнта економічності кровообігу (КЕК), індексу Робінсона (ІР) та коефіцієнта витривалості (КВ) можемо діагностувати адекватність реакції організму на ФН, оцінити адаптаційні можливості, функціональні резерви ССС, використовувати для підбору й моніторення величини адекватних ФН, оскільки ці показники в спортсменів ВК нижчі в стані спокою та в період відновлення. Найбільш точними маркерами адекватності реакції організму на впливи екстремальних навантажень виявилися показники ударного об’єму (УО), ударного індексу (УІ) й індексу на- пруження міокарда (ІНМ), оскільки вони по-різному змінювалися в спортсменів ВК та НК і при ФН, і в період відновлення.

EFFECTIVENESS INDICATORS OF USING ETHNIC GAMES FOR THE IMPROVEMENT OF PHYSICAL STATUS AND ENDURANCE LEVEL OF PEOPLE IN MID-MOUNTAIN REGIONS (AGE PERIOD: 50-55 YEARS)

The article presents the effectiveness indicators of a brand new methodology developed by Kyrgyzstan. It focuses on application of outdoor ethnic games for the improvement of health status and endurance level of adults aged 50-55 in mid-mountain regions. The obtained results are applicable for the refinement of training process and the improvement of physical qualities of elderly people in special climate conditions. We analyzed the indicators of physical fitness, physical status, adaptive potential and endurance of adults aged 50-55. The outcomes demonstrated effectiveness of using outdoor ethnic games for the improvement of health status and the deceleration of age-related changes in the studied group. The reason is that all ethnic games have an active impact on all muscle groups, develop motor qualities and raise endurance. The purpose is to develop the methodology of application of outdoor ethnic games for the improvement of physical status and workability of persons of pre-retirement age in mid-mountain regions in Kyrgyzstan and to determine its effectiveness. Research methods: anthropometry, physiometry (body length, body weight, heart rate, blood pressure); functional tests: Davydenko 6-scale momentum test (Cooper test); methods of mathematical statistics. Results: In our research, we first identified the indicators of adaptive potential, the nature of adaptation, characteristics of functional state, physical status, and stamina level according to Davydenko 6-scale momentum test. We assessed the functional state of cardiovascular system according to the endurance coefficient. We used 12-minute Cooper test and monitoring of maximum oxygen consumption to identify the physical fitness degree of individuals of pre-retirement age who practice outdoor ethnic games in mid-mountain regions in Kyrgyzstan. Conclusion. We carried out the comparative analysis of current functional adaptation status of men playing ethnic games. The first observation revealed the decrease in body functional abilities. The second observation revealed the tension of adaptation mechanisms in men and women. Both men and women had either medium or high physical status. The studied group practicing modern physical culture demonstrated the same results and the same physical status. Results of Davydenko test show the increasing fitness level in both groups. Functional indicators of studied groups demonstrate the intensification of cardiac activity. It provides sufficient functional capabilities at the cost of functional reserves. Level of physical capacity degree in studied groups: satisfactory, good and high. The index of maximal oxygen consumption demonstrate good health of people in both groups.

World records in running: The experience of ergometric analysis

Analysis of record achievements in athletics has almost a century of history. The leading method during the study was the ergometric measurement method. Ergometric analysis of the results was performed proceeding from the relationship between the length of the distance and the limit time to overcome it. Analysis of record curves at different running distances was performed on the basis of the technique proposed by N.I. Volkov. To analyse the growth of record achievements, we also applied the logarithmic transformation of exponential dependence. Ergometric analysis of record curves displayed that with each new exponential spike in the improvement of results, an increase in the endurance coefficient is noted. It was established that athletes who train to overcome long running distances have better ergometric indicators characterizing aerobic performance: they are characterized by a higher coefficient of critical and a less pronounced decrease in the curve of the dependence speed – time. And middle-distance athletes were characterized by large values of power factor, which gives clear advantages upon performing intense muscular work. The data obtained by us in the analysis of record achievements in short distances and the forecast of records for these distances allowed to distinguish four stages throughout the history of record achievements in athletics, within each of which occurred a radical reorganization of the training methodology used.

ANALYSIS OF THE CARDIOVASCULAR SYSTEM IN SIMULATED CONDITIONS

Aim. The article deals with establishing the correlations between the anthropometric, hemodynamic, and vegetative tone indicators in first and second-year students during their adaptation to university conditions. The morphophysiological status of students was corrected by Selenes+ and additional physical load. Materials and methods. Students aged 17–20 years (n = 60) participated in a longitudinal study. The following physiological methods were used: body length and mass measurement; BMI calculation; detection of selenium in blood serum; systolic and diastolic pressure measurement; heart rate calculation; average dynamic pressure calculation; pulse pressure calculation; stroke volume calculation using Starr’s equation; minute volume blood flow calculation; endurance coefficient calculation according to Kvass’ equation; functional changes index calculation; Kerdo vegetative index calculation. Results. It was established that application of selenium depending on physical load in first-year female students influenced significantly the following indicators: arterial pressure (F = 4.21), heart rate (F = 3.42), minute volume blood flow (F = 3.80), functional changes index (F = 10.65), systolic pressure (F = 4.72; P < 0.05); selenium concentration (F = 93.97; P < 0.001). At the end of the IV stage, statistically significant F-criteria for arterial pressure (F = 3.50), heart rate (F = 4.33), endurance coefficient (F = 4.78; Р < 0.05), systolic pressure (F = 5.92), pulse pressure (F = 5.50; P < 0.01), functional changes index (F = 10.65), selenium concentration (F = 41.11; P < 0.001) were registered. Conclusion. The correlations revealed between the anthropometric, hemodynamic, and vegetative tone indicators in first and second-year students allowed to make a conclusion about the efficiency of the Selenes+ supplement during adaptation to university conditions. The Selenes+ supplement combined with physical exercises contributes to less pronounced stress in the cardiovascular system and provides the physiological optimum of the body.

Influence of Loading Frequency on Fatigue of Construction Materials

Investigations have been carried out in respect of structural steel and titanium alloy fatigue at various cyclic loading frequencies and these investigations have made it possible to reveal regularities in changes of parameters pertaining to fatigue resistance and stability behaviour of the tested materials. A change in cyclic loading frequency affects duration of a single (during one cycle) stay of the material in the loaded state and it has an impact on its durability. In addition, with an increase in frequency of load cycles, deformation rate becomes higher, and stress build-up time is decreasing, while distortion of a crystal lattice is increasing due to reduction of time for development of a weakening process. This process is accompanied by an increase in intensity of grain crushing into fragments and blocks, and their disorientation. Tests on cyclic strength of the studied material samples have been carried out at various frequencies and at a room temperature according to the following loading schemes: cantilever cyclic transverse bending of a flat sample; cantilever bending with rotation of a cylindrical sample; axial tension on a pulsating cycle. Quantitative estimates of a fatigue resistance index in the form of slope tangent in a left branch of the fatigue curve to a cycle axis have been used in order to analyze and evaluate performance and stability of the tested materials. Methods for mathematical statistics have been applied to process the obtained results. Graphic dependences of fatigue curves have been plotted in logarithmic coordinates that allowed to obtain straightening of approximating lines for experimental data. The investigations have revealed that loading frequency has an ambiguous effect on fatigue resistance due to some differences in materials in respect of their reaction to changes in a load spectrum within different areas of the fatigue process, but at the same time it has been found that an increase in fatigue strength leads to a slope decrease in the fatigue curve regardless of a decrease or an increase in a load frequency. The paper proposes a new approach to assess a cyclic strength and durability of materials, and it comprises a system of parameters including a relative coefficient of limited endurance, a correlation coefficient and a slope tangent of the fatigue curve. Behavior dynamics for real machine parts and structures made of these alloys under operating conditions has been indicated in the paper.

Implementation of Pump Installation Simulation with Smart Relay-Based Water Level for Practical Tools in Learning Process

Polytechnic is a skill-based education with a lot of training and practice, it is necessary to be prepared practicum facilities in terms of instrumentation and control devices, especially pump installation system. An important role in the operation of a system is the electrical system in the form of control, which is useful to facilitate pump installation operation system and this piping is called the Water Level Control. The complicated difficulty is assembling electrical installations manually. This problem can be solved with water level control pump installation system based on smart relay. The aim of this research is to know the discharge of pump water. The data show the average of the water debit calculation theoretically 1.03 liters / minute, meanwhile the average of the debit of test water on tool is 1.44 liter / minute. In conclusion, there is a difference about 0.41 liters / minute, the determination of frictional factor price, coefficient of endurance, pipe diameter, bend type in the specification material not in accordance with the actual material size. It is suggested to the policy makers in the field of vocational education that the tools and practical facilities must be well designed to more effectively consider the condition of student learning.

Method of selecting step stress test parameters for XLPE insulation DC voltage endurance coefficient

Cross-linked polyethylene (XLPE) insulation DC voltage endurance coefficient (VEC) is an important basis in the selection of DC cable insulation design and factory test parameters. Studies on the degradation of XLPE insulation performance under DC electric field can also provide technical support for the reliability evaluation of cable operation. The step stress method as an efficient electrical life test method is widely used to obtain VEC. The parameters of step stress method present considerable influences on VEC. An analytical method based on the trajectory of the damage curve and equivalence between step stress test and constant stress test within zone division is proposed in this paper. According to the proposed method, several sets of step stress tests with different test parameters have been carried out. The accuracy of the test results has been confirmed via analyzing test data. The experimental results show that the VEC (n=12.0) obtained by the step stress test whose parameters are selected by proposed method has good equivalence with the result (n=12.2) under constant-stress method.

Adaptive capacity of the cardiovascular system in children with rheumatic diseases and comorbid conditions

Purpose: to study the functional state of the cardiovascular system and its adaptive reactions in children with rheumatic diseases, taking into account the development of comorbid conditions. Materials and methods. 44 patients with RD were examined, 8 of them with systemic lupus erythematosus, 36 with juvenile idiopathic arthritis. The average age of the children was 13.39 ± 0.82 years. To study tolerance to the minimum physical activity and its influence on the state of the CVS in children, a six-minute walk test (SMWT) was conducted. To assess the functional intensity of the CVS, the following indices were calculated before and after the SMWT: Allgower index, endurance coefficient according to Kvas formula, Robinson index, coefficient of circulatory efficiency. To assess the influence of the vegetative nervous system (VNS) on the CVS activity, Kerdo vegetative index (KVI) was determined. At rest, the functional changes index (FCI) of the circulatory system, or the adaptation potential (AP), was also determined. Results. In patients with RD, there is a reduced tolerance to minimal physical activity with an increase in the functional tension of the cardiovascular system and activation of the sympathetic division of the autonomic nervous system. When analyzing the functional stress of the cardiovascular system in children with RD and the presence of comorbid pathology, significantly higher values of the adaptation potential and Allgower index were revealed, which indicates the formation of disturbances in the circulatory system against the background of the breakdown of the adaptation mechanisms of the cardiovascular system. The KVI indicates activation of the sympathetic part of the autonomic nervous system in them and an increase in the catabolism processes characteristic for intense functioning with the expenditure of the body's energy reserves. When evaluating these indicators in children without comorbid conditions, the negative KVI value indicates activation of the parasympathetic division of the VNS, which indicates a more favorable, anabolic variant of the shift and more economical mode of functioning of the body systems. Conclusions. Children with RD showed a decrease in tolerance to the minimum physical load in the SMWT, as evidenced by the percentage increase in heart rate and the distance traveled. Tension in the cardiovascular system’s work and a decrease in its functional capabilities were also revealed, as evidenced by a significant increase in the Robinson index, Allgower index and the endurance coefficient both before and after the SMWT. In children with RD and the presence of comorbid pathology, higher values of adaptation potential, Allgover index and Kerdo vegetative index were established, which indicates the formation of disturbances in the circulatory system against the background of the breakdown of its adaptive capabilities.

HYGIENIC ASSESSMENT OF HEMODYNAMIC PARAMETERS OF SCHOOLCHILDREN AND STUDENTS WITH DIFFERENT MOTOR ACTIVITY LEVEL

We studied the functional state of the cardiovascular system in 997 schoolchildren of Ufa and 597 students of the Bashkir State Medical University with different levels of physical activity. All subjects were divided into 3 groups depending on the level of physical activity: the first group (control) consisted of schoolchildren and students, which do not involve in sports outside the school and university programs, with the lowest physical activity compared with other groups; the second group included persons with an average level of physical activity, who in addition to physical education classes independently engage in physical culture: running, walking, outdoor games and daily morning exercises; the third group consisted of schoolchildren and students regularly engaged in sports clubs and sections, having the highest level of physical activity. The following hemodynamic parameters were calculated: systolic blood volume, minute blood volume, pulse pressure, fatigue coefficient, blood circulation efficiency ratio, Robinson index. The data obtained for each group were subjected to statistical analysis separately for males and females in the age aspect. We have established the positive influence of regular physical education and sports on the metabolic and energy processes in the heart, which in turn leads to an improvement in the main indicators of the cardiovascular system. Thus, among schoolchildren and students regularly engaged in physical culture and sports, significantly lower values of minute blood volume, blood circulation efficiency ratio, endurance coefficient, Robinson index and high values of systolic blood volume, pulse pressure were noted. The presence of reliable direct correlation of the weak degree of physical culture and sports with the majority of studied hemodynamic parameters was revealed.

Evaluation of voltage endurance characteristics for new and aged XLPE cable insulation by electrical treeing test

The voltage endurance coefficient of solid insulating materials can be determined by electrical treeing tests. The measured value is influenced by the test conditions, and its effectiveness remains to be further demonstrated. In this study, samples were made from the XLPE insulation of three 110 kV AC cables, two new and one operated for 16 years. In treeing tests performed with a pin-plane electrode system, the tree initiation times were measured under both progressive and constant voltage, and voltage endurance coefficients were determined by the residual voltage method. The material properties of XLPE were measured using the FTIR, DSC and TSC methods. For the same sample, the voltage endurance coefficient measured with a 10 μm needle electrode was larger than that measured with a 5 μm electrode, indicating the influence of space charges on the electrical field around the needle tip. For the insulation samples of the two new cables, the measured voltage endurance coefficients were different, and the difference became more significant when the rise rate of the progressive voltage decreased. The superior resistance to electrical aging of the insulation with a higher voltage endurance coefficient was confirmed via material property measurements. For the insulation samples of the aged cable, along with a decrease of the progressive voltage rise rate, the tree initiation voltage increased, which was opposite to the test results obtained for the new cable insulation samples. The voltage endurance coefficient could not be measured using the residual voltage method because the trees always initiated at the rising edge of the constant voltage, except for a low value measured at the lowest constant voltage. The abnormal performance of the aged cable insulation might be the result of increased defects and impurities caused by operation aging, which enhanced the space charge effect, especially in the pin-plane electrical field of the electrical treeing test.

Adaptive possibilities of the cardiovascular system in adolescents with non-inflammatory diseases of the myocardium, taking into account the functioning of the right ventricle of the heart

Adaptation of the cardiovascular system to physical activity implies the development of functional or structural changes that should ensure the most efficient and economical use of energy during muscular contraction. The most studied data reactions in individuals engaged in various sports. The aim of our study was to study the functional changes of the heart, taking into account the functioning of the right and left ventricles of the heart and the adaptive capacity of the cardiovascular system in children with non-inflammatory diseases of the myocardium. Were examined 62 patients with non-inflammatory myocardial diseases, whose mean age was 14.56 ± 0.24 years. The control group consisted of 41 practically healthy peers. The functional state of the myocardium was assessed according to the results of the ultrasonic Doppler study of the heart in the “M” and “B” - modes, as well as in the mode of constant-wave and color scanning with a convex sensor using the standard method. To study tolerance to the minimum physical activity and its influence on the state of the cardiovascular system in children, a six-minute walk test was conducted. To assess the functional intensity of the cardiovascular system before and after the six-minute walk test, the following vegetative indices were calculated: an endurance coefficient according to the formula A. Quaasa and a double product. The vegetative Kerdo index and adaptation potential were calculated at rest. As a result of the study, it was found that in children with myocardial pathology, stress is observed in the adaptation mechanisms of the cardiovascular system, accompanied by a weakening of its functional capabilities and an increase in the work of the cardiac muscle at rest. This happens against the background of a decrease in the functioning of the left ventricle and an increase in the functioning of the right ventricle of the heart. These changes are accompanied by activation of the parasympathetic division of the autonomic nervous system in patients in all the studied groups, which indicates a more economical mode of functioning of the body systems.

Adaptation of Foreign Students to Sharply Continental Climate of the Volgograd Region

This article is about the adaptative reactions of the cardiovascular system of foreign students from the warm countries to the sharp continental climate of the Volgograd region. The research includes the assessment of anthropometrical data of physical development, parameters of hemodynamics in the conditions of operational rest and the state of functional test (active orthostatic test). A foreign students insufficiency of physical development, deficiency of body mass is noted. Amongst them, persons with asthenic type of constitution prevail. In a condition of operational rest, a foreign students increase in systolic blood pressure and decrease coefficient of endurance of cardiovascular system which confirms work of a myocardium in tension mode is revealed. In the state of orthostatic test, multidirectional changes of systolic blood pressure, increase in diastolic blood pressure and sharp decrease in pulse pressure were noted indicating tension and instability of cardiovascular system activity. Functional adaptation of foreign students to climate-geographical factors of the Volgograd region is complicated by influence of complex social factors which are connected with new living conditions and increase in educational activity in the university.

Endurance of the wooden bridge reinforced by the dowel plates

Abstract The most important piece of road infrastructure is bridges. Wooden bridges have advanced constantly during the past decades. The trend began in Scandinavian countries but has also now gained significant ground in Russia. This research studies experimental endurance potential of the joints of the wooden beam while considering the coefficient of asymmetry of the cycle, which corresponds to the actual operating conditions. Performance analysis of the composite bars is carried out based on the experiment; the development of a special methodology for calculating the joints of wooden elements with the dowel plates for their better endurance is also introduced in this paper. The results of experimental studies on the performance of bending composite wooden bridge bars based on dowel plates operating under cyclic influences thus determine the endurance limit of wood for composite wooden bridge beams based on dowel plates. The calculation technique and interdependence of the endurance coefficient affecting the asymmetry coefficient of the bent composite wooden bridge bars on the dowel plates under cyclic loading are considered. The experimental data on the endurance of composite wooden bridge beams have been obtained, and separate analysis has been made of the compounds under cyclic loading performance; a method has been developed for calculating the bent composite wooden bridge bars reinforced by the dowel plates under cyclic influences.

Acids generated and influence on electrical lifetime of natural ester impregnated paper insulation

Acids have attracted an increasing interest from researchers for the standard evaluation of transformer oil, especially in natural ester. This study aims to investigate the types of generated acids in natural ester under hydrolysis, oxidation, and accelerated thermal aging tests with varying paper moistures. The oxidation and hydrolysis degrees were evaluated by acid number and kinematic viscosity, and acids were distinguished from aging condition hydrolysis of oil paper insulation by combining pH values. Meanwhile, the electrical lifetime of oil-paper insulation with seven types of acid were analyzed by step-stress test. The two-parameter Weibull distribution was used to analyze the mean lifetime of specimens statistically. Experimental results reveal that the majority of acids generated from hydrolysis and the main acids are long-chain fatty acids of natural ester impregnated paper insulation. Furthermore, the electrical lifetime models of oil-paper insulation with different types acid were established, and the voltage endurance coefficient with seven types of acids were also obtained. The electrical lifetime test indicated that acids can reduce the electrical lifetime of natural ester impregnated paper insulation and that the effect of low-molecular-weight acids on insulation lifetime is approximately 2–3 times higher than high-molecular-weight acids.

ФУНКЦИОНАЛЬНОЕ ОБЕСПЕЧЕНИЕ СПЕЦИАЛЬНОЙ РАБОТОСПОСОБНОСТИ У КВАЛИФИЦИРОВАННЫХ БОКСЕРОВ ПРИ ВЫПОЛНЕНИИ СПЕЦИАЛИЗИРОВАННЫХ ТЕСТОВ АНАЭРОБНОГО ХАРАКТЕРА

Introduction. The overwhelming majority of researchers solved the issue of improving the special working capacity of boxers without taking into account the variety of mechanisms that determine the manifestation of this quality in this sport and without taking into account the requirements imposed on the boxer by a competitive duel. Purpose. when performing specialized tests in the conditions of anaerobic energy supply, to determine the features of the manifestation of special working capacity of qualified boxers and its functional support, taking into account the specifics of the competitive activity in the box. Methods. Studies were conducted with the participation of 28 qualified boxers, which were divided into groups depending on the versions of the boxing tournaments: amateurs, semi-professionals and professionals. To estimate theof special working capacityusedtechnique of detectionthe basic parametersof performanceboxersSpuderg-10. Toestimate the responseof cardiorespiratory systemduring the «test 8 s» and «test 40 s»was used a portableergo-spirometrycomplex«Meta Max 3B» (Cortex,Germany). Results. Boxers-professionals have a higher level of speed-strength performance and a greater coefficient of explosive endurance indicates a retention of the tempo of percussion by boxers-professional when performing a short-term load of maximum intensity. A significantly lower level of speed-strength performance is noted in boxers-amateur with a greater rate of impact at the beginning of the test than at the end. A high rate of impact, even with short-term work of anaerobic creatine phosphate character (test 8 s), causes a more pronounced reaction of the cardiorespiratory system during the testing load and in the recovery period. The higher degree of positive correlation of the number of strikes with the level of CO 2 emission was revealed, than with the level of consumption of O 2 , which confirms the greater value of respiratory compensation for the increasing degree of acidosis even when performing a short-term high-intensity physical load of anaerobic creatine phosphate nature.To demonstrate a high coefficient of explosive endurance, a more economical type of respiratory reaction with a higher level of consumption of O 2 and CO 2 emissions is favorable. Conclusion. It is shown that the differences of qualified boxers in terms of the level of anaerobic creatine phosphate and anaerobic glycolytic capabilities, in terms of speed-strength performance and explosive endurance. For the first time it was revealed that when carrying out loads of anaerobic nature in order to achieve a higher level of special working capacity of qualified boxers, greater importance is attached to a greater level of activity of aerobic processes in energy supply with a greater degree of efficiency of functional and metabolic reactions.