Growth Of Muscle Mass Research Articles

Justification of the effective sequence of group fitness classes with second mature women (45-55 years old)

This article deals with issues that are aimed at the organization of strength training. First of all, it is necessary to note significant differences between women and men in terms of strength. In women, they are 15-20% lower than in men. Women have a lower tendency to gain muscle mass. This is primarily related to the hormonal background, since the male hormone testosterone is responsible for the growth of muscle mass, and its amount in the body of women is many times smaller than that of men. At the same time, women's ability to display strength indicators of leg muscles is close to men's. Experts in age-related physiology note that at the age of 40-45, reverse processes begin in a woman's body. The main metabolism slows down, the productivity of various organs and systems decreases, the possibility of various pathological processes, chronic diseases, etc. increases. In connection with the decrease in the hormonal background, negative changes are observed in all organs and systems of the body. Blood pressure often rises, a tendency to osteoporosis appears, fat metabolism is disturbed, which often leads to an increase in body fat. There are significant changes in the respiratory system, the vital capacity of the lungs decreases, the mobility of the chest decreases. After 40 years, there is a significant decrease in muscle strength in women. The elasticity of muscles, tendons, and joint performance is lost. At the same time, muscle tone decreases, which leads to negative changes in posture.

Protein intake by master swimmers: Implications for practice in Sports Nutrition-A cross-sectional study.

Background: Proteins are essential for the maintenance, repair, and growth of muscle mass. This is particularly important for master athletes because aging has been associated with loss of muscle mass, function, and strength. Moreover, the timing of intake has been shown important for the best protein utilization. Aim: To analyze timing, quantity, and source of dietary protein in competitive master athletes according to current recommendations. Methods: Twenty-one male master swimmers (47.9 ± 10.0 years; 79.2 ± 6.5 kg; 179.1 ± 5.5 cm; 23.5 ± 4.9% body fat; 73.3 ± 4.2% lean mass) participated in this cross-sectional study. Protein intake was analyzed based on 7-day food records, regarding quantity, timing, and sources of intake. Protein intake was evaluated according to current international sports nutrition guidelines, including the International Society of Sports Nutrition Position Stand. Body fat (%) and lean mass (%) were evaluated using dual-energy X-ray absorptiometry. Results: Participants' mean protein intakes were 1.9 ± 0.5 g/kg/day, 0.6 ± 0.2 g/kg/meal post-training, and 33.5 ± 23.9 g during the pre-sleep period. Daily intake was within the recommended values of 1.4 and 2.0 g/kg/day (p = 0.01 and 0.147, respectively). Mean pre-sleep intake was within the recommendation values of 30-40 g (p = 0.28 and 0.147, respectively). Most of the daily protein intake was consumed at lunch (66.7 ± 6.9 g) and dinner (48.0 ± 4.5 g). Regarding protein sources, intakes from animal, vegetal, and supplements were, respectively, 65.7%, 29.2%, and 5.1%. Conclusion: Master swimmers presented a total protein intake within the recommendations for a daily basis, but the majority of intake was at lunch and dinner. Protein intake could be better distributed throughout the day to optimize protein synthesis. Guidance on daily protein intake distribution should be reinforced in clinical practice.

Morphological and functional spleen development in crossbreed rabbits

The accelerated growth of muscle mass in productive broiler breeds is often associated with delayed organ development of integral body systems, particularly the immune structures. The spleen is the largest secondary immune organ in the mammalian body and is responsible for initiating immune responses to blood-borne antigens. It can only perform this function successfully if all of its tissue components are fully morphologically and functionally mature. The spleen was studied in meat production rabbits (early maturing crossbreed Hyplus) at 1, 10, 20, 30, 60 and 90 days of age. Morphological studies included anatomical dissection, clarification of topography, determination of mass parameters, preparation of smears and histological sections. Spleen histological sections were stained with haematoxylin and eosin, according to Van Gieson, and impregnated with silver nitrate, followed by microscopy. Qualitative and quantitative indicators of spleen cellular and tissue component development were determined using ImageJ software. It was found that in crossbred rabbits the topography of the spleen corresponds to general anatomical principles of localisation, has a fixed place and is an anatomically formed organ. In day-old animals, the histological differentiation of the spleen is limited to the connective tissue stroma and the parenchyma. The organ's parenchyma is formed by reticular tissue, with hematopoietic and lymphoid cells among the cells, without differentiation into white and red pulp. In 10-day-old rabbits, the white pulp is represented by the periarterial lymphatic sheath (PALS) and marginal zones. Single primary lymphoid nodules without germinal centres are seen in the spleen from 20 days of age. By 30 days of age, the white splenic pulp has all the major structural and functional zones, including formed lymphoid nodules with germinal centres and mantle zones. During the second and third months of life, the spleen gradually increases the relative area of all white pulp functional zones, reaching a maximum at 90 days of age. In productive rabbits, the cellular composition of the splenic white pulp is represented by lymphocytes (small, medium, large), reticular cells, macrophages and plasma cells. During postnatal ontogenesis, the number of small lymphocytes increases in all white pulp functional zones, reaching maximum values in 90-day-old animals. On the contrary, the relative number of medium and large lymphocytes decreases. The number of reticulocytes in the periarterial lymphatic sheath and lymphoid nodules zones does not change significantly, and in the marginal zone it decreases substantially by the end of the study. The results of determining the timing of morphological and functional maturation of immunocompetent structures in the spleen of meat rabbits are of great biomedical and economic importance. They will serve as a control for comparing changes in rabbit spleen lymphoid tissues during the development of pathological processes, as well as under the influence of external factors.

The life-course changes in muscle mass using dual-energy X-ray absorptiometry: The China BCL study and the US NHANES study.

Sarcopenia is an important indicator of ill health and is linked to increased mortality and a reduced quality of life. Age-associated muscle mass indices provide a critical tool to help understand the development of sarcopenia. This study aimed to develop sex- and age-specific percentiles for muscle mass indices in a Chinese population and to compare those indices with those from other ethnicities using the National Health and Nutrition Examination Survey (NHANES) data. Whole-body and regional muscle mass was measured by dual-energy X-ray absorptiometry (DXA) in participants of the China Body Composition Life-course (BCL) study (17203 healthy Chinese aged 3-60years, male 48.9%) and NHANES (12663 healthy Americans aged 8-59years, male 50.4%). Age- and sex-specific percentile curves were generated for whole-body muscle mass and appendicular skeletal muscle mass using the Generalized Additive Model for Location Scale and Shape statistical method. Values of upper and lower muscle mass across ages had three periods: an increase from age 3 to a peak at age 25 in males (with the 5th and 95th values of 41.5 and 66.4kg, respectively) and age 23 in females (with the 5th and 95th values of 28.4 and 45.1kg, respectively), a plateau through midlife (30s-50s) and then a decline after their early 50s. The age at which muscle mass began to decline was 52years in men with the 5th and 95th percentile values of 43.5 and 64.6kg, and 51years in women with the 5th and 95th percentile values of 31.6 and 46.9kg. Appendicular skeletal muscle mass decreased earlier than whole body muscle mass, especially leg skeletal muscle mass, which decreased slightly after age 49years in both sexes. In comparison with their US counterparts in the NHANES, the Chinese participants had lower muscle mass indices (all P<0.001) and reached a muscle mass peak earlier with a lower muscle mass, with the exception of similar values compared with adult Mexican and White participants. The muscle mass growth rate of Chinese children decreased faster than that of other races after the age of 13. We present the sex- and age-specific percentiles for muscle mass and appendicular skeletal muscle mass by DXA in participants aged 3-60 from China and compare them with those of different ethnic groups in NHANES. The rich data characterize the trajectories of key muscle mass indices that may facilitate the clinical appraisal of muscle mass and improve the early diagnosis of sarcopenia in the Chinese population.

Effects of omega-3 supplementation on muscle mass growth: an umbrella review of systematic reviews of randomised controlled trials

Effects of omega-3 supplementation on muscle mass growth: an umbrella review of systematic reviews of randomised controlled trials

Training of volleyball players at the beginning of their sports career

The analysis of scientific and methodical literature let us state that physical training of school age children is very important. In this article we consider some aspects of young volleyball players physical training using different tools: physical exercises, games, competitions etc. taking into account laws of growing and developing child’s organism. Children should start playing volleyball since 11-12 years old. For this age it is characteristic the rapid body development, an increase in growth of muscle mass and strength. As well intensively develop attention, memory, will, quick thinking. The ability to perceive, memorize complex movements, analysis of their actions increase. Children with mental focus are able to perform complex movements and improve their quality. It should be remember that at this age child's body is not unique to rapid fatigue, and rapid recovery of working capacity. Therefore, the training process is necessary to diversify as much as possible exercises.&#x0D; Thus, we know that the process of morphofunctional development of school-aged children depends to some extent on external living conditions and the nature of the activity carried out by students, to a large extent from the targeted use of physical education resources. The skillful use of specially selected and correctly dosed physical exercises during the period of enhanced deployment of natural morphofunctional development contributes to the stimulation, ordering and intensification of the relevant processes, ultimately achieving a significant increase in the functional capabilities of all body systems. At later age stages, when the peaks of natural development of certain functions are overdue, it is difficult and even impossible to achieve similar results [1].

Kinesiological models of the neuromuscular system readaptation in mature women after prolonged hypokinesia

Purpose&#x0D; To study the peculiarities of adaptive and compensatory reactions in mature women after prolonged hypokinesia using various kinesiological models of the neuromuscular system readaptation.&#x0D; Material and methods&#x0D; 52 women of mature age (39-46 years) after long-term (6-7 years) hypokinesia took part in the study. Group A used a kinesiological model based on free weight exercises with changes in kinematic and dynamic characteristics. Group B used a model based on machine exercises. The following methods were used to monitor adaptation processes: bioelectrical impedance analysis, anthropometry, testing of strength capabilities, biochemical blood analysis (cortisol and creatinine concentration).&#x0D; Results &#x0D; The dynamics of the studied indicators differed significantly between the groups using the proposed kinesiological models for 12 weeks. Thus, the fat-free and body cell mass indicators were 5 times higher in group A women compared to group B participants. The body fat mass decreased by 5 times in group A participants. The circumference measurements reduced in all participants, but in group A the rate of change was 1.8 times faster. The level of strength growth was almost the same in all study participants; it fluctuated within 10-25% compared to the initial data. The cortisol concentration in the blood serum increased only in group B during all stages of control. At the end of the research, the cortisol level did not change in response to stress in the women of group A, which indicates increasing of their resistance level. The basal level of creatinine grew by 4% in group A women after 12 weeks of training, but it did not change in group B participants. These changes indicate an accelerated growth of muscle mass in group A women.&#x0D; Conclusions&#x0D; Pronounced adaptive changes occurred in women of mature age after prolonged hypokinesia in case of using the kinesiological model of the neuromuscular system readaptation with free weight exercises. Applying this model helps to increase the functional capabilities of the body, to strengthen the level of resistance to a stress stimulus, and to improve the morphometric parameters of the body.

Application and progress of blood flow restriction training in improving muscle mass and strength in the elderly.

As an emerging training method, blood flow restriction training has been proved to promote the growth of muscle mass and strength. In recent years, it has been gradually applied in different populations. However, there are few studies on how blood flow restriction training affects muscle mass and strength in the elderly. The relevant literature is compiled and summarized in this study. Through the comparison of blood flow restriction training with traditional training methods and its application in the elderly, it shows that blood flow restriction training can effectively increase muscle mass and strength, prevent muscle atrophy, improve cardiopulmonary function, facilitate injury and postoperative rehabilitation, and intervene in related degenerative diseases as a training method suitable for the elderly,. The main mechanism of blood flow restriction training promoting muscle mass and strength growth is metabolic stress response, including muscle fiber recruitment, protein synthesis signal pathway activation, hormone secretion, etc., and is also related to cell swelling caused by pressure. At present, although the application of blood flow restriction training in the elderly population is increasing, there is a lack of personalized programs. In the future, more research on the dose effect and safety of blood flow restriction training is needed to develop more accurate personalized training programs.

Plant and animal protein for muscle mass and strength gains: a systematic review

Background: Controversial approaches to studying the effect of proteins of various origins on the functional parameters of human skeletal muscles have led to the erroneous opinion that plant-based protein is a lesser stimulator of muscle mass growth and muscle strength than animal protein. Therefore, the purpose of this systematic review was to actually evaluate the effects of plant and animal protein intake on muscle mass and strength through studies comparing protein supplements.Methods: Literature search was carried out in the databases PubMed, Research Gate and the database of the Russian State Library. Studies were considered both in English and in Russian, over the past 20 years, filtered by date: from July 2002 to July 2022. Inclusion Criteria: Participants are healthy men and women over 18 years of age; taking protein supplements from plant products (soy, wheat, pea, rice, etc.); comparison with a group taking protein supplements from animal products (whey, beef, egg, etc.); studies assessed lean and/or muscle mass and assessed participants' muscle strength before and after supplementation; randomized controlled trial.Results: A total of 970 studies were found. After initial screening for title and abstract, 938 studies were excluded. Of the 32 publications selected, 5 duplicates were excluded, and after a secondary selection, 18 studies that did not meet the PICOS criteria were excluded. As a result of the search and selection, the review included 9 publications.Conclusions: Athletes and active individuals who prefer to consume plant-based protein products may not be inferior in terms of muscle strength and muscle mass to those athletes who prefer animal-based protein products. To further explore this topic, more randomized controlled trials should be conducted, taking into account the requirements for standardization and with a large number of participants.Registration: PROSPERO 2022 CRD42022345245

ВЛИЯНИЕ РОСТА СКЕЛЕТНО-МЫШЕЧНОЙ МАССЫ НА ПОКАЗАТЕЛИ ОБМЕНА ЖЕЛЕЗА У ВОЕННОСЛУЖАЩИХ ПО ПРИЗЫВУ В ПЕРИОД АДАПТАЦИИ К УСЛОВИЯМ ВОЕННОЙ СЛУЖБЫ

Thousands of young men are conscripted for military service with various nutritional status and physical fitness condition every year. The adaptation of conscripted soldiers to the factors of military service occurs at three levels: physiological, psychological and social. The purpose of the study was to assess the dynamic changes of body structure parameters in conscripted soldiers during 6 months of service by conscription and to determine the effect of skeletal muscle mass growth on iron metabolism during adaptation to military service conditions. A prospective observational study involved 145 conscripted soldiers from one of the military units after informed consent. The study was performed from the moment of conscription for military service in 3 stages with an interval of 3 months using a four-component model of body structure and a four-component model of iron metabolism. The skeletal muscle mass and adipose tissue mass and were determined caliperometrically. Hematological and biochemical parameters of iron metabolism were assessed. Dynamic changes and types of growth of the skeletal muscle mass, as well as changes in the parameters of iron metabolism have been obtained. The body weight of conscripted soldiers changes slightly within 6 months from the moment of conscription. At the same time internal changes occurred in the structure of the body of conscripted soldiers due to an increase in skeletal muscle mass and a decrease in the mass of adipose tissues. The types of skeletal muscle mass growth were determined among conscripted soldiers. There were an increase in skeletal muscle mass and hemoglobin fund to provide them oxygen by the influence of increased physical loading. It led to a decrease in iron stores, estimated by serum ferritin, and signs became more pronounced of iron deficiency erythropoiesis, which were determined in erythrocyte indexes. These combined changes can be assessed as functional iron deficiency or iron deficiency without anemia.

Network Analysis Identifies Circulating MicroRNA Associated With Muscle Mass Gains In Resistance Trained Older Adults

Purpose: Age related muscle loss (sarcopenia) is a major contributor to functional disability and all-cause mortality. Rescuing muscle mass in older adults has been most effective with resistance exercise training (RT). We have previously demonstrated that 3d/wk of heavy RT in older adults may blunt the hypertrophic response to progressive resistance training. We postulate that this effect may be mediated by epigenetic factors, such as, microRNA (miRNA), resulting in impaired muscle mass growth. We hypothesize that insufficient recovery time may contribute to attenuated hypertrophic responses to RT if intensive loading occurs too frequently (i.e. 3 d/wk). The present study is a follow up molecular analysis of two RT cohorts from our previous clinical trial (NCT02442479) in which optimal exercise dose for aging individuals (60-75y) was determined from four RT cohorts. That trial determined that a dose consisting of 2 d/wk high-intensity RT separated by a low-intensity, concentric only day (HLH) was superior to 3 d/wk high-intensity RT (HHH) for thigh lean mass gains. Methods: The present study sequenced circulating miRNA from serum exosomes pre- and post- 35 weeks of RT in 19 individuals that underwent either HLH or HHH RT. Subsequent analysis was performed via weighted gene co-expression network analysis (WGCNA) to identify modules of eigengenes with miRNA membership correlated with treatment and thigh lean mass gains. Network analysis and visualization of these modules were performed. Results and Conclusion: WGCNA identified modules correlated with treatment (p = 0.03, p = 0.05) and with thigh lean mass gains (p = 0.006 and p = 0.01) at the final time point (35wk). Pathway analysis provides insight into regulated pathways that may be attributed RT frequency and subsequent magnitude of thigh lean mass hypertrophy between the two treatment groups. Altogether, this analysis reports on a molecular exercise response in aging individuals that may better inform exercise dose optimization, as well as, deepen our understanding of inter-individual response heterogeneity. Supported by T32HD071866 and P2CHD086851.

The UHPLC-MS/MS determination of ostarine in food supplements for athletes

Ostarine, also called enobosarm or MK-2866, is one of the Selective Androgen Receptor Modulators (SARMs). A number of preclinical data suggest the beneficial use of these substances to increase muscle mass growth and bone density. Unlike anabolic steroids, they have suppressed androgenic side effects and are therefore thought to be useful in the treatment of health conditions associated with insufficient muscle growth. For the same reason, substances from the SARMs group are abused in sports and bodybuilding. They have been added on the World Anti-Doping Agency (WADA) list in 2008 and their use in sports is prohibited. In many countries, products containing these substances are available through a number of e-shops offering supplements for athletes. The positive effects on muscle growth and body fat loss and the absence of side effects are emphasized. Because SARMs are banned in sports and are not approved for any therapeutic use, they are marketed as “Research Only”. However, the products are sill quite popular among athletes. As with anabolic steroids, there are a variety of dosing regimens for both beginners and advanced athletes, which end up recommending a combination of three to four SARMs over several weeks. Although more extensive clinical data are lacking, case studies are beginning to appear describing liver damage or heart attack in people taking ostarine or other SARMs products. However, due to the lack of clinical data, no positive or negative effect on the organism is objectively confirmed. For these reasons, it is very appropriate to have an analytical method available that allows the rapid and correct determination of the ingredients in preparations that have ostarine declared in the list of ingredients. Equally important is the possibility of identifying this substance in preparations that should not contain any active substance and appear as purely natural products. For the ostarine determination a simple and fast UHPLC-MS/MS method was developed. For extraction of ostarine the content of the studied capsule was weighted and transferred to a volumetric flask, which was then made up with methanol to 100 mL. The mixture was shaken for one hour. After filtration 10 μL of extract was transferred to a new flask and made up to 5 mL with 10% methanol with 0,1% acetic acid and 10 mM ammonium acetate. This solution was used for UHPLC-MS/MS analysis. An UHPLC system Infinity 1290 and chromatographic column Eclipse Plus C18 (50 × 2.1 mm; 1.8 μm) (both Agilent Technologies, USA) were used for the separation. 0.1% acetic acid and 10 mM ammonium acetate in water and methanol were chosen as mobile phases for gradient elution. For the MS/MS detection 6460 Triple Quadrupole mass spectrometer (Agilent Technologies, USA) with negative ESI ionization were used. For dynamic MRM mode two transitions of m/z were chosen for the detection: 388.1 → 117.9 and 269.0. Limit of detection was 0.2 ng/mL and limit of quantification 0.5 ng/mL. The method was used for quantitation of ostarine in dietary supplements for athletes. The content of ostarine in one capsule ranged from 10 to 15 mg and did not differ from the quantity indicated on the label. The described method is suitable for the determination of ostarine and can be used in toxicological and forensic practice.

Myokines in obese adolescents with aerobic exercise

Myokines are synthesized by myocytes and released into the bloodstream in response to muscle fiber contraction. They have a positive effect on carbohydrate and lipid metabolism, muscle mass growth, osteogenesis, increase tissue sensitivity to insulin, counteract inflammation of adipose tissue. The study of their secretion in response to physical activity (FA) can help to personalize the therapy of obesity. to study the features of the secretion of myokines in children with constitutionally exogenous obesity during physical activity of different duration and intensity and to evaluate their relationship with the parameters of the body composition. 26 children (10 boys and 16 girls) were included in the study 15 [13; 16] years old, SDS BMI: +2.91 [2.24; 3.29], with sexual development according to Tanner 4-5. Two groups of 13 people were formed by random distribution. Group I performed FA (walking on a treadmill under the control of heart rate) of different duration: 30 and 60 minutes at the same intensity (less than 3 metabolic equivalents (MET)). Group II - FA of different intensity: low - less than 3 METH and moderate - 3-6 METH with the same duration of 45 minutes. Commercial kits for enzyme immunoassay were used to determine the level of myokines. The assessment of the compositional composition of the body was carried out by bioimpedance analysis (analyzer In Body 770, South Korea) in the morning, on an empty stomach. Statistical processing was carried out using STATISTICA v.12.0 (StatSoftInc., USA). The results are presented in the form of median (Me) and quartiles (Q1; Q3) corresponding to 25 and 75 percentiles. The critical significance level (p) was assumed to be <0.05. moderate intensity FA leads to a maximum increase in the level of myokines: interleukin-6 (IL-6) by 215.7% and decorin by 34.3%, a decrease in the level of irisin by 16.5%. An hour-long low-intensity workout leads to a moderate increase in the level of IL-6 by 80.5%, to a decrease in the level of irisin by 31.1%. Myostatin increases equally both after 60-minute FA and after moderate intensity FA by 30.9% and 31.8%, respectively. Short low-intensity FA (lasting 30 minutes) it is not accompanied by a significant increase in the expression of myokines. The relationship between the amount of muscle (r=0.65), lean (r=0.62), fat-free mass (r=0.64) and the level of decorin after FA was noted. There was no statistically significant relationship between the parameters of the body composition and the levels of IL-6, myostatin, and irisin. There were no gender differences in both basal and stimulated myokine secretion. Moderate intensity FA and low intensity 60-minute FA are most effective for obese children. A 30-minute low-intensity FN is insufficient to increase the secretion of myokines by skeletal muscles.

Mechanisms of muscle mass

In the course of the work, the study of the main mechanisms of increasing muscle mass for beginners is carried out. As a result of the work carried out, it was revealed that with the right training method, balanced food and good sleep, the growth of muscle mass occurs much faster.

Effects of different exercise programs on cardiorespiratory fitness and body composition in college students

Background/ObjectivesThe cardiorespiratory fitness (CRF) of college students is showing a downward trend, this study aimed to explore the effects of three exercise programs on CRF and body composition indicators in college students. MethodsA total of 50 non-smoking, healthy and physically inactive students were recruited from campus in Beijing, China, and randomly assigned to 4 groups: low-intensity continuous training with blood flow restriction (LICT-BFR, n = 13), moderate-intensity continuous training (MICT, n = 13), high-intensity interval training (HIIT, n = 12), and no exercise control (n = 12), the intervention continued for 8 weeks. Body composition and aerobic capacity were measured before and after the intervention. ResultsExercise groups reached significant improvements in maximal oxygen uptake (VO2max, p < 0.01) and a decrease in body fat percentage (p < 0.05) comparing to the control group. The fat mass and visceral fat area reduced significantly (p < 0.05) with a muscle mass growth (p < 0.05) in the LICT-BFR and MICT groups comparing to the control group. Changes of fat and muscle mass were trivial in the HIIT group (p = 0.842, p = 0.247). ConclusionAll three exercise programs can improve the CRF of college students, with LICT-BFR has the most profound effects, and MICT is more beneficial for body composition improvement than other programs. From an overall perspective, LICT-BFR should be the ideal choice, however, due to limited equipment, college students can choose MICT or HIIT according to their situations.

The thymus regulates skeletal muscle regeneration by directly promoting satellite cell expansion

The thymus is the central immune organ, but it is known to progressively degenerate with age. As thymus degeneration is paralleled by the wasting of aging skeletal muscle, we speculated that the thymus may play a role in muscle wasting. Here, using thymectomized mice, we show that the thymus is necessary for skeletal muscle regeneration, a process tightly associated with muscle aging. Compared to control mice, the thymectomized mice displayed comparable growth of muscle mass, but decreased muscle regeneration in response to injury, as evidenced by small and sparse regenerative myofibers along with inhibited expression of regeneration-associated genes myh3, myod, and myogenin. Using paired box 7 (Pax7)-immunofluorescence staining and 5-Bromo-2′-deoxyuridine-incorporation assay, we determined that the decreased regeneration capacity was caused by a limited satellite cell pool. Interestingly, the conditioned culture medium of isolated thymocytes had a potent capacity to directly stimulate satellite cell expansion in vitro. These expanded cells were enriched in subpopulations of quiescent satellite cells (Pax7highMyoDlowEdUpos) and activated satellite cells (Pax7highMyoDhighEdUpos), which were efficiently incorporated into the regenerative myofibers. We thus propose that the thymus plays an essential role in muscle regeneration by directly promoting satellite cell expansion and may function profoundly in the muscle aging process.

Women and strength training

Strength training does not constitute women’s favourite physical activity. It is demonstrated in the survey conducted by Budzyńska at the University of Szczecin in 2013 among students of the Pedagogical Faculty. Only 1% of the surveyed students showed interest in strength training. The vision of a bodybuilding silhouette discourages women from taking up strength training. It is displayed in the survey conducted by Zaustowska in 2001 among junior high school students. Out of 78 respondents, 71 stated that they did not like the muscular figure. These fears are unfounded since a woman’s body is not disposed to achieve a bodybuilding figure. It depends on the structural, morphological and biochemical properties of one’s body. Some women who practice bodybuilding rely on strength training additionally supporting the growth of muscle mass with nutrients. This paper presents the advantages of applying strength training in everyday physical activity. These include fat reduction and a slim figure. Furthermore, the result of strength training is a relative increase in muscle mass and strength development. Another benefit of this form of activity is the strengthening of the structures which stabilize joints and bones thus reducing the risk of injury. The duration of static exercise depends on the applied load. Due to the short duration of static effort and relatively high strength commitment, energy for working muscles comes from anaerobic changes. ATP, phosphocreatine and a small amount of glycogen which are hydrolyzed. During the static exercise blood pressure and heart rate are increased. These changes are dependent on the size of the strength developed to oppose resistance. A heavy load used during the static exercise often causes reflex respiratory arrest, a dangerous phenomenon resulting in fainting during the exercise.

Athletic gymnastics. Basics of nutrition. Harmful health effects from anabolic steroids and doping

Rest and nutrition between workouts is a very influential and important part of an athlete's life. This time should be spent correctly, bringing the maximum benefit to the organism, after all efficiency of the next physical activities depends on rest. Proper nutrition is a premature and indispensable contribution to the success of heavy sports. No matter how intense and long the classes in the gym, they will not bring the desired effect without the right diet. It is very difficult for a modern person to calculate his food down to the smallest detail, count every calorie and avoid fast harmful snacks. But there are immutable rules - the principles of proper sports diet. If they are successfully implemented, then it will be possible to switch to special programs. So, the most important rule - That is, you need time!&#x0D; Every novice athlete should remember that when doing bodybuilding, all food should be divided into special segments - meals every three hours, after which you need to eat. You need to eat at least 5-6 times a day. For example, a butter bun and a glass of protein can be considered a meal. Distribute the number of calories consumed evenly throughout the training day. At the same time, you should not try to adhere to a strict calorie intake. Abrupt jumps and failures in your diet will only hinder the growth of muscle mass. When doing sports, breakfast comes first, because during this time you have to consume a significant amount of calories. The appropriate number of calories is recommended to consume after exercise, when the body requires large amounts of nutrients and trace elements. The first and fifth meals with a balanced diet are the most important periods. When eating out, make sure you have enough first-class protein in your diet to digest amino acids. Doctors recommend eating chicken, eggs, beef, all kinds of protein shakes and other dairy products.

Embryonic thermal manipulation of Japanese quail: effects on embryonic development, hatchability, and post-hatch performance.

Embryonic thermal manipulation led to several modifications in molecular, physiological, and biochemical parameters which affect pre- and post-hatch growth performance. The current study aims to elucidate the onset and long-term effects of intermittent thermal manipulations (TM) during two-time windows, early/late, of embryogenesis in Japanese quail (Coturnix japonica) on embryonic development, hatchability, muscle histogenesis, and post-hatch growth performance. Four groups were created; quail eggs in the control group were incubated at 37.7 °C and relative humidity (RH) 55%. Three thermally treated groups were incubated intermittently at 41 °C and 65% RH intermittently (3 h/day): early embryogenesis group (EE) was thermally treated during embryonic days (ED) 6-8, late embryogenesis group (LE) was thermally treated during (ED12-ED14), and early and late embryogenesis group (EL) was thermally manipulated in both time windows. Relative embryo weights in EL and EE were significantly lighter than those in LE and Ctrl groups. The hatched chicks were reared under optimal managemental conditions (three replicates per treatment). Average daily feed intake was recorded, and feed conversion ratio (FCR) was calculated. Histological and quantitative analyses of muscle fibers were performed. The results revealed that TM led to significant hypertrophy of quail breast muscle in (EE). Intermittent short-term (3-6 h) thermal manipulation (39-40 °C) protocols during early embryogenesis (ED6-ED8) could be recommended to enhance muscle mass growth and breast muscle yield in the Japanese quail.

Genistein–a supplement improving efficiency of the human body: A review

In our review, we have compiled and discussed studies relating to the effects of genistein on the efficiency of the human body. Genistein is a compound classified to isoflavones, phytoestrogens and polyphenols. It is found in many products, such as soy, potatoes or beans. (So far, many studies confirming the healthy effects of this compound to the body have been conducted. One of the aspects of genistein is its effect on exercise capacity. It reduces adipose tissue, inhibits cytodifferentiation of adipocytes and also prevents lipogenetic processes. It also lowers cholesterol and triglycerides levels. It shows myoprotective effect, preventing muscle atrophy and damage, and also affects the growth of muscle mass. It reduces the concentration of cortisol, commonly called stress hormone, which has an negative effect on fat metabolism and skeletal muscle. It also supports glucose transport and regulates carbohydrate metabolism, reducing insulin resistance. However, due to estrogen-like action, it lowers testosterone levels. Genistein is a potential nutrient for physically active people. Dans notre revue, nous avons compilé et discuté des études relatives aux effets de la génistéine sur l’efficacité du corps humain. La génistéine est un composé classé parmi les isoflavones, les phytoestrogènes et les polyphénols. On le trouve dans de nombreux produits, tels que le soja, les pommes de terre ou les haricots. Jusqu’à présent, de nombreuses études confirmant les effets sains de ce composé sur le corps ont été menées. L’un des aspects de la génistéine est son effet sur la capacité d’exercice. Il réduit le tissu adipeux, inhibe la cytodifférenciation des adipocytes et empêche également les processus lipogénétiques. Il abaisse également les niveaux de cholestérol et de triglycérides. Il montre un effet myoprotecteur, prévenant l’atrophie musculaire et les dommages, et affecte également la croissance de la masse musculaire. Il réduit la concentration de cortisol, communément appelée hormone du stress, qui a un effet négatif sur le métabolisme des graisses et les muscles squelettiques. Il prend également en charge le transport du glucose et régule le métabolisme des glucides, réduisant la résistance à l’insuline. Cependant, en raison de son action semblable à celle des œstrogènes, elle abaisse les niveaux de testostérone. La génistéine est un nutriment potentiel pour les personnes physiquement actives.