Prevent Muscle Damage Research Articles

Long-Term Moderate Exercise Combined with Metformin Treatment Induces an Hormetic Response That Prevents Strength and Muscle Mass Loss in Old Female Wistar Rats.

Sarcopenia is a syndrome characterized by a progressive and generalized skeletal muscle mass and strength loss, as well as a poor physical performance, which as strongly been associated with aging. Sedentary lifestyle in the elderly contributes to this condition; however, physical activity improves health, reducing morbidity and mortality. Recent studies have shown that metformin (MTF) can also prevent muscle damage promoting muscular performance. To date, there is great controversy if MTF treatment combined with exercise training improves or nullifies the benefits provided by physical activity. This study is aimed at evaluating the effect of long-term moderate exercise combined with MTF treatment on body composition, strength, redox state, and survival rate during the life of female Wistar rats. In this study, rats performed moderate exercise during 20 of their 24 months of life and were treated with MTF for one year or for 6 months, i.e., from 12 to 24 months old and 18 to 24 months old. The body composition (percentage of fat, bone, and lean mass) was determined using a dual-energy X-ray absorption scanner (DXA), and grip strength was determined using a dynamometer. Likewise, medial and tibial nerve somatosensory evoked potentials were evaluated and the redox state was measured by HPLC, calculating the GSH/GSSG ratio in the gastrocnemius muscle. Our results suggest- that the MTF administration, both in the sedentary and the exercise groups, might activate a mechanism that is directly related to the induction of the hormetic response through the redox state modulation. MTF treatment does not eliminate the beneficial effects of exercise throughout life, and although MTF does not increase muscle mass, it increases longevity.

Comparison of Sit and Reach Test, Straight Leg Raise Test and Visual Analogue Scale When Applying Static Stretching and Mulligan's Two Leg Rotation in Young Adults with Hamstring Shortness

Purpose: This study compared the effects of Static stretching and Mulligan’s Two-leg rotation about the Hamstring flexibility, Hip range of motion, and pain. Methods: The subjects were allocated randomly into two groups: Static stretching group (n=13) and Mulligan’s two leg rotation group (n=14). The study was designed with stretching protocols for four minutes and thirty seconds per day five times a week for three weeks in total. Measurements, including the Sit and reach test, Active/Passive Straight leg raise, and Visual analogue scale, were conducted be fore and after the intervention. The data were analyzed using a paired t-test and independent t-test. Results: The flexibility of the two leg rotation group was higher than the static stretching group after the intervention. The post-sit and reach test value of the two leg rotation group was significantly higher than the pre-sit and reach test value of the static stretching group. In addition, the variance of the sit and reach test of the two leg rotation group was significantly higher than that of the static stretching group. Conclusion: These results showed that two leg rotation techniques have a positive effect on the changes in the sit and reach test and active straight leg raise test. Two leg rotation techniques can be recommended as a self-stretching and easier way to stabilize the lum bopelvic rhythm, reduce the stiffness of the muscle and relieve pain. This is effective in preventing muscle damage, enabling muscle re laxation and reducing the risk of injury to the spine during daily lives and in sports activities.

The Role of Ultrasound Assessment in Achilles Tendon Pathology

AbstractBackground: Tendons are connective tissues that transmit the force produced by muscle to bone and also prevent muscle damage by acting as shock absorbers. The Achilles tendon is the single largest, thickest and strongest tendon in the human body that transmit the force of powerful calf muscles to foot facilitating walking and running. This has long been known as a site susceptible to disabling injury. Forces up to 12 times bodyweight may arise during sporting activity. US performed with high-resolution linear-array probes has become increas-ingly important in the assessment of ligaments and tendons around the ankle because it is low cost, fast, readily available, and free of ionizing radiation.Aim of the Work: To provide an overview of clinical applications of ultrasound in assessment of pathological Achilles tendons. And to demonstrate the role of ultrasound in diagnosis of Achilles tendon pathology after clinical diag-nosis.Patients and Methods: This study is a prospective study, it was conducted in Radiology Department at Ain-Shams University Hospitals (El-Demerdash) from September 2018 till March 2019. It included 20 patients who were referred from the orthopedics, sports medicine and physical medicine outpatients.Results: In our study US was capable of detecting almost all Achilles tendon abnormalities with high accuracy. The main noticeable limitation was the assessment of the bone marrow. In our study, the sensitivity, specificity and accuracy for US for Achilles tendon were 100%, 75% and 95% respec-tively. Both US and MRI are used in the evaluation of super-ficial structures, such as tendons and ligaments. The choice between US and MRI in such evaluations is determined by availability, referring physician preference, and the experience of the radiologist because in many settings accuracies can be similar.Conclusion: Ultrasonography is an accurate and sensitive modality in evaluation of the Achilles tendon, it and can be used either as primary tool of investigation or as complemen-tary tool with MRI and even in some cases may be used as a final method of diagnosis without need for further correlation with any other imaging techniques.

Impact of Magnesium Supplementation in Muscle Damage of Professional Cyclists Competing in a Stage Race.

Magnesium is a cofactor of different enzymatic reactions involved in anabolic and catabolic processes that affect muscular performance during exercise. In addition, it has been suggested that magnesium could participate in maintaining muscle integrity during demanding effort. The main purpose of this study was to analyze the effects of magnesium supplementation in preventing muscle damage in professional cyclists taking part in a 21-day cycling stage race. Eighteen male professional cyclists (n = 18) from two teams were recruited to participate in the research. They were divided into 2 groups: the control group (n = 9) and the magnesium-supplemented group (n = 9). The supplementation consisted of an intake of 400 mg/day of magnesium during the 3 weeks of competition. Blood samples were collected according to World Anti-Doping Agency rules at three specific moments during competition: immediately before the race; mid competition; and before the last stage. Levels of serum and erythrocyte magnesium, lactate dehydrogenase, creatinine kinase, aspartate transaminase, alanine transaminase, myoglobin, aldolase, total proteins, cortisol and creatinine were determined. Serum and erythrocyte magnesium levels decreased during the race. Circulating tissue markers increased at the end of the race in both groups. However, myoglobin increase was mitigated in the supplemented group compared with the controls. We conclude that magnesium supplementation seems to exert a protective effect on muscle damage.

Protective effect of supplementation with Lycium ruthenicum Murray extract from exhaustive exercise-induced cardiac injury in rats.

To the Editor: Lycium ruthenicum (L. ruthenicum) Murray contains abundant anthocyanins. The purpose of the present research was to investigate the protective effect of L. ruthenicum extract supplementation on the damage from exhaustive exercise in rats which were treated for seven days before the exhaustive exercise. Exhaustive exercise induced an increase of Serum nitrate (NO) and reactive oxygen species (ROS) levels, but supplementation of L. ruthenicum extract reduced them significantly (P < 0.05). Interleukin (IL)-1 and IL-6 were also significantly reduced by L. ruthenicum as compared to the control (P < 0.05). Supplementation with L. ruthenicum extract also decreased the creatine kinase isoenzyme MB (CK-MB) generation significantly and ameliorated the myocardial histopathology. L. ruthenicum belongs to the genus Lycium of the family Solanaceae and is a salinized desert plant distributed mainly in Qinghai and Xinjiang Provinces of China. Recently, studies have shown that L. ruthenicum exhibits a wide range of pharmacologic properties, such as anti-oxidation, anti-fatigue, and hypoglycemic activity.[1,2] Anthocyanins and their aglycones from L. ruthenicum have strong antioxidant activity.[3] Anthocyans are flavonols, which occur ubiquitously in the plant kingdom and confer bright red or blue coloration on berries and other fruits and vegetables. Anthocyanin concentration in the L. ruthenicum extract was determined by using the Nakata method[4] and the concentration in the L. ruthenicum extract was 24.1 ± 7.7 mg/g. However, we know anthocyanin has antioxidant properties and ROS induced by extreme temperatures can be protected by anthocyanins in several plants. Anthocyanin has an antioxidant role in plants against ROS and extreme temperatures. Exercise-induced oxidative stress has been reported and antioxidant supplementation can prevent muscle damage, protective effects on the endocrine-metabolic and immune profile.[5] Therefore, L. ruthenicum extract should have a protective effect against oxidative stress and we investigated that the possible protective effect of L. ruthenicum extract and anthocyanin supplementation on the oxidative stress generated by exhaustive exercise in SD rats. In this study, 30 Sprague-Dawley (SD) rats, males and aged 6 weeks, were randomly assigned to the control, anthocyanin (5 mg/rat as the positive control), and other three groups were given L. ruthenicum extract in distilled water orally (as vehicle, 10 and 30 mg/rat), for 7 days before the exhaustive exercise stress. Rats of the exhaustive exercise group were subjected to graded treadmill running started at 10% grade, 15 m/min for 10 min followed by gradual increases of treadmill speed and time as 25 m/min for 20 min, 28 m/min for 20 min, 31 m/min for 20 min, 34 m/min for 20 min, 37 m/min for 20 min until exhaustion. The heart was dissected and washed with saline for fixation with formalin. Exhaustive exercise causes oxidative stress and is defined as the inability of rats to run on the treadmill despite a mild electrical shocking.[6] Add some information on dietary antioxidants for exercise-induced oxidative stress.[7] Regular exercise is recommended for a healthy life, but exhaustive exercise generates the excessive oxidative stress that may exceed the beneficial effect from the regular exercise.[8] In the present study, an increasing CK-MB activity from the cardiac muscle consisted of myocardial damage was seen in tissue vacuoles and cell death from heart tissue. Exhaustive exercise also induced an increase of serum NO, ROS, IL-1, IL-6, and CK-MB levels, but supplementation of L. ruthenicum extract reduced them significantly. Supplementation with L. ruthenicum extract also significantly ameliorated the myocardial histopathology. Under the microscope, the photographs showed the heart section with a 400× magnification. The severity of damage in the exhaustive exercise group was exhibited by vacuoles and dead cells. However, changes in histopathology were significantly reduced by the treatment with anthocyanin and L. ruthenicum extract [Figure 1].Figure 1: Protective effect of Lycium ruthenicum extract on the exhaustive exercise-induced myocardial injury. Histopathology (hematoxylin and eosin staining) of myocardial slices from rats from (A) no treatment control group; (B) the exhaustion group; (C) the Anthocyanin group, exhaustive exercise treatment supplemented with 5 mg Anthocyanin/rat; and (D) the L. ruthenicum extract group, exhaustive exercise treatment supplemented with 30 mg L. ruthenicum/rat. Photographs show the myocardial section with 400× magnification. Tissue vacuoles (hollow triangle arrow heads ▿) and cell death (nuclei stained, black arrow heads ◂) were more severe in exhaustion than those in control or L. ruthenicum groups.In conclusion, 1-week oral supplementation of L. ruthenicum extracts present positive effects on the oxidative stress generated by exhaustive exercise in SD rats, possibly via promotion of antioxidant capacity. The mechanism of protection of L. ruthenicum extract supplementation was not investigated in this study and waits for further study in the future. Acknowledgements The authors are grateful for text proofreading support from Prof. Kee-Ching Jen. Funding None. Conflicts of interest None.

Tempol, a superoxide dismutase mimetic agent, improves dystrophic phenotype in the diaphragm muscle of mdx mice

Duchenne muscular dystrophy (DMD) is a progressive and lethal X‐linked myopathy, in which the oxidative stress and abnormal reactive oxygen species (ROS) production plays a key role in its pathophysiology. Despite intense efforts, no cure is currently available for DMD and glucocorticoids are the only effective drug to slow down disease progression. Thus, in the present study we investigated Tempol (a superoxide dismutase mimetic agent) effects on the diaphragm muscle of mdx mice, an experimental model of DMD. Mdx mice were randomly divided into two groups: mdxS, the control group receiving intraperitoneal (i.p.) injections of saline solution (100μL) and mdxT, the treated group receiving i.p. injections of Tempol (100 mg/kg). C57BL/10 mice were also used as controls. The results showed that Tempol treatment prevented muscle damage indicated by gain in muscle strength, decrease in the IgG uptake by muscle fibers and reduction of regenerated muscle fibers indicated by the central nuclei. It also had an effect on the inflammatory process, reducing the inflammatory area, macrophage staining and decreasing TNF‐α, IL‐1β and IL‐6 levels. Regarding oxidative stress, Tempol treatment was effective in reducing ROS and lipid peroxidation in the dystrophic diaphragm muscle. The findings presented here show that Tempol treatment improves dystrophic phenotype, supporting its use as a potential therapeutic strategy in DMD.Support or Funding InformationFAPESP #2017/01638‐0CAPES FAEPEXThis abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.

Effects of ascorbic acid supplementation on oxidative stress markers in healthy women following a single bout of exercise

BackgroundAscorbic acid is a water-soluble chain breaking antioxidant. It scavenges free radicals and reactive oxygen species (ROS), which are produced during metabolic pathways. Exercise can produce an imbalance between ROS and antioxidants, leading to oxidative stress-related tissue damages. This study was designed to determine the effects of ascorbic acid supplementation on circulating biomarkers of oxidative stress and muscle damage following a single bout of exercise.MethodsIn a crossover design with a 1 wk. wash-out period, 19 healthy women performed 30 min moderate-intensity cycling after ingesting 1000 mg of ascorbic acid (AA) or placebo. Blood samples were taken immediately before, immediately after and 30 min post-exercise to determine plasma albumin, total protein, glucose, oxidative stress and muscle damage markers.ResultsPlasma albumin and total protein levels increased immediately after exercise in placebo alongside slight reductions in glucose (p = 0.001). These effects were absent in AA cohort. Ferric reducing ability of plasma and vitamin C levels in AA cohort significantly increased after exercise (p < 0.05). Superoxide dismutase activity was significantly elevated after exercise (p = 0.002) in placebo but not AA. Plasma malondialdehyde did not change after exercise in placebo but was significantly decreased in AA (p < 0.05). The exercise protocol promoted slight muscle damage, reflected in significant increases in total creatine kinase in all subjects after exercise. On the other hand, plasma C-reactive protein and lactate dehydrogenase remained unchanged.ConclusionSupplementation with ascorbic acid prior exercise improves antioxidant power but does not prevent muscle damage.

RAAVrh74.MCK.GALGT2 Protects against Loss of Hemodynamic Function in the Aging mdx Mouse Heart.

Dilated cardiomyopathy is a common cause of death in patients with Duchenne muscular dystrophy (DMD). Gene therapies forDMD must, therefore, have a therapeutic impact in cardiac as well as skeletal muscles. Our previous studies have shown that GALGT2 overexpression in mdx skeletal muscles can prevent muscle damage. Here we have tested whether rAAVrh74.MCK.GALGT2 gene therapy in mdx cardiac muscle can prevent the loss of heart function. Treatment of mdx hearts with rAAVrh74.MCK.GALGT2 1day after birth did not negatively alter hemodynamic function, tested at 3months of age, and it prevented early left ventricular remodeling and expression of fibrotic gene markers. Intravenous treatment of mdx mice with rAAVrh74.MCK.GALGT2 at 2months of age significantly improved stroke volume and cardiac output compared to mock-treated mice analyzed at 17months, both at rest and after stimulation with dobutamine. rAAVrh74.MCK.GALGT2 treatment of mdx heart correlated with increased glycosylation of α-dystroglycan with the CT glycan and increased utrophin protein expression. These data provide the first demonstration that GALGT2 overexpression can inhibit the loss of cardiac function in the dystrophin-deficient heart and, thus, may benefit both cardiac and skeletal muscles in DMD patients.

Muscles Heating Analysis in Sportspeople to Prevent Muscle Injuries using Thermal Images

Muscle heating is the process that every athlete follows before any physical activity or sport which are the legs where greater force is exerted and in case a good heating routine is not practiced, the muscles can suffer tears, cramps or fractures due to sudden movements while the muscles are cold. According to the National Institute of Arthritis and Musculoskeletal and Skin Diseases of the United States, the most common injuries occur in the ankles because it is a central point where greater force is exerted by the induced weight of the athletes, in addition if excessive muscle care is important. That is why the evaluation of muscle heating in athletes to prevent muscle damage was raised in this research work, first two thermal images of the before and after heating will be obtained using the FLIR ONE Pro thermal camera following a protocol of distance, position and temperature range, then the images are processed in the MATLAB software to map them in the temperature range and then subtract them to obtain the zones where the temperature variations are found indicating where an adequate heating has been carried out. As a result, the areas where the subtraction of both images was positive were obtained, this new image of the subtraction is superimposed on the real image, showing the real image with the areas where it has proceeded with an optimal heating.

Sport and energy drinks consumption before, during and after training

Summary Aims Sports drinks, when used by adult athletes, can have significant performance benefits. Sports drinks provide carbohydrates, electrolytes and fluids to the body, and help the body hydration, before, during, and after physical activity. The carbohydrates supply the muscles with fuel during exercise. The main electrolyte from sport drinks is sodium, which improves the drive to drink and can assist with fluid replacement. One of the main aim of using sport drinks is hydration, without decreasing sodium level in order to prevent hyponatremia. The addition of protein may be beneficial to prevent muscle damage and may improve or maintain subsequent performance over consecutive days. Other active ingredients (as vitamins) may play a role in energy metabolism or in free radical defense, but are usually found in small amounts and it is unclear if they have any direct performance benefits. Caffeine improves reaction time and if consumed few hours before anaerobic/resistance exercise may improve the performance, but has no effect on repeated high-intensity training. Conclusion Sport drinks are useful only for adults athletes involved in endurance training, but are not recommended for children and adolescents. Sport drinks have the proper amounts and concentrations of carbohydrates and electrolytes to help the physical performance, in comparison with energy drinks, caffeinated energy drinks or other beverages.

An 8-Week Ketogenic Diet Alternated Interleukin-6, Ketolytic and Lipolytic Gene Expression, and Enhanced Exercise Capacity in Mice.

Adjusting dietary fat intake is reported to affect mitochondrial biogenesis and fatty acid oxidation (FAO), and thus may enhance exercise capacity. However, a high-fat diet where carbohydrate intake is not limited enough also makes it difficult for athletes to maintain weight, and may fail to force the body to utilize fat. As such, a low-carbohydrate, high-fat, ketogenic diet (KD) may be viable. We have previously reported that an eight-week KD enhances exercise capacity, and suggested the mechanism to be enhanced lipolysis and ketolysis. In the present study, we investigated how an eight-week KD alters mRNA expression during fatty acid mobilization, FAO and ketolysis. We found that an eight-week KD may remodel the lipid metabolism profile, thus contributing to influence exercise capacity. We also found that ketolysis, lipolysis and FAO adaptations may contribute to enhanced exhaustive exercise performance. Along with enhanced FAO capacity during exhaustive exercise, a KD may also alter IL-6 synthesis and secretion profile, thus contribute to fatty acid mobilization, ketolysis, lipolysis and preventing muscle damage. Both the lipid metabolism response and IL-6 secretion appeared to be muscle fiber specific. Taken together, the previous and present results reveal that an eight-week KD may enhance exercise performance by up-regulating ketolysis and FAO ability. Therefore, a KD may have the potential to prevent muscle damage by altering IL-6 secretion profile, indicating that a KD may be a promising dietary approach in endurance athletes, sports, and for injury prevention.

Beneficial effects of metformin on muscle atrophy induced by obesity in rats.

A growing interest to understand the signaling pathways mediating obesity-induced muscle atrophy is given. Metformin (Met) was reported to possess positive effects on preventing muscle damage and promoting muscle mass maintenance. The aim of the present study to investigate pathways involved in Met effect on obesity induced muscle atrophy. Thirty adult male albino rats were assigned into two groups: normal chew diet fed group as control group (C; n = 10) and high-fat-diet (HFD) fed group ( n = 20). After 16 weeks, the HFD-fed animals were subdivided into two groups; HFD group ( n = 10) and HFD fed treated with oral Met (320 mg/day) treatment (Met, n = 10) for 4 weeks. At the end of the experiment; final body weight, visceral fat weight, fasting blood glucose, insulin, lactate, total cholesterol, triglycerides were measured and calculated homeostatic model assessment insulin resistant (HOMA-IR) for all groups. Soleus muscle weight, histopathlogical examination and expression of peroxisome proliferator-activated receptor-γ coactivator-1α (PGC-1α), forkhead box O3 (FoxO3), atrogin-1/MAFbx, and muscle RING finger 1 (MuRF-1) were performed. HFD-fed animals showed significant increase in final body weight, visceral fat mass, fasting blood glucose, insulin, calculated HOMA-IR, lactate, total cholesterol and triglycerides with significant decrease in soleus muscle weight, PGC-1α and significant increase in FoxO3, atrogin-1/MAFbx, and MuRF-1 expression. Also, there was significant decrease in fiber diameter, myosin heavy chain (MHC) I content while collagen content and myosin heavy chain IIa were increased compared with control group. Met-treated group showed a significant decrease in the measured parameters compared with the HFD group. It also restored the gene expression, morphometric measures and MHC composition toward normal. The current study is the first to provide evidence that Met could ameliorate muscle atrophy in high-fat diet induced obesity and this effect may be in part due to regulation of PGC-1α-FoxO3 pathway.

PO-202 Monitoring Chinese Table Tennis Players Physical Function Preparing for the Swedish World Table Tennis Championships

Objective In this paper, five people of the national table tennis men's team are selected as the research objects, and the blood biochemical index of the athletes are measured and analyzed. To understand and master the current physical fatigue and physical function recovery of key athletes based on the test results, and provide reasonable training program and sports nutrition supplements advice for key athletes, so that athletes can achieve the best physical condition, improve training effect and performance.&#x0D; Methods On April 10, 2018, at 7:15 in the morning, blood was collected from five main athletes in the fasting state, and blood biochemical analysis was performed to record athletes' white blood cell(WBC), hemachrome, blood urea nitrogen, creatine kinase(CK), testosterone/cortisol(T/C) and other biochemical index. And compared with the same period last year, to assess the physical performance of athletes. &#x0D; Results 1: The white blood cell values of the five main athletes were within the normal range(4.0-11.0), and there was significant improvement compared with the same period of last year; the hemoglobin values of the five main athletes were relatively well within the normal reference range(110-170) and increased compared with the same period last year.&#x0D; 2: Analysis of blood urea nitrogen results showed that Wang Chuqin and Ma Long's blood urea nitrogen measurement value was higher than the normal value (4.0-7.0); compared with the same period of last year, Ma Long blood urea nitrogen value increased by 33.3%; other members blood urea nitrogen value was within the normal range and there was no significant change compared to the same period last year.&#x0D; 3: Analysis of creatine kinase results showed that the CK levels of Wang Chuqin, Xu Xin and Ma Long were higher than the normal values ​​(50-310); compared with the same period of last year, the CK value increased by 263%. The CK value of Ma Long increased by 76.3%; other athletes CK value were in the normal range and stable.&#x0D; 4: Testosterone/Cortisol results showed that the T/C ratio of the five main athletes was &gt;0.03, which was in the normal range, and there was no significant change compared with the same period of last year.&#x0D; Conclusions 1: The five main athletes have good immune function and are good for ensuring disease resistance before and during the game.&#x0D; 2: The aerobic metabolism level of the male member is relatively good, which is beneficial to the body's aerobic endurance level. And compared with the previous aerobic endurance test results, the male aerobics members' aerobic capacity is in a stable state.&#x0D; 3: The blood urea nitrogen is relatively low in the normal reference range, indicating that the athletes are more suitable for the current training load and intensity, and the body recovers well; Wang Chuqin and Ma Long have better adaptation to the current training intensity.&#x0D; 4: Some atheletes have higher levels of CK. It is recommended to strengthen the positive recovery of muscle tension and relaxation after high-intensity training to better prevent muscle damage.&#x0D; 5: At present, the proteolysis and metabolism of the male member of the main is greater than of protein synthesis, and they five should increase the targeted supplement of dietary protein, vitamins and other nutritional supplements to improve testosterone levels.

Creatine monohydrate supplementation during eight weeks of progressive resistance training increases strength in as little as two weeks without reducing markers of muscle damage

Creatine supplementation (Cr) increases strength during resistance training, but the time course of this strength increase is unclear. The aim was to determine the precise time course by which Cr could increase strength and whether Cr prevents muscle damage during eight weeks of resistance training. Young males were randomized (double blind) to Cr (N.=9, 0.07g/kg/d) and placebo (N.=9) during 8-weeks of resistance training (3 d/week). Strength was assessed across six exercises every two weeks. Venous blood samples obtained at baseline, and 24 and 48 hours after the final resistance training session were assessed for creatine kinase [CK] and lactate dehydrogenase [LDH] as measures of muscle damage. Strength was significantly higher in the Cr versus placebo group (P<0.05) after two weeks of training for three of the six exercises (bench press, leg press, shoulder press). By the end of the eight weeks of training, strength was significantly higher in the Cr versus placebo group (P<0.05) for four of the six exercises (bench press, leg press, shoulder press, and triceps extension, but not biceps curl or lat-pulldown). Creatine supplementation did not prevent muscle damage. Indeed, muscle damage markers increased in the Cr compared to placebo group (P<0.05). Cr increased muscular strength in as little as two weeks during a resistance training program; however, this was not accompanied by decreased muscle damage. Greater muscle damage with Cr may be due to a greater training intensity enabled by Cr supplementation. This might lead to greater protein turnover and enhanced muscle adaptation.

Taurine: A Potential Ergogenic Aid for Preventing Muscle Damage and Protein Catabolism and Decreasing Oxidative Stress Produced by Endurance Exercise.

The aim of this study was to evaluate the effects of taurine and chocolate milk supplementation on oxidative stress and protein metabolism markers, and aerobic parameters in triathletes.Methods: A double-blind, crossover study was conducted with 10 male triathletes, aged 30.9 ± 1.3 year, height 1.79 ± 0.01 m and body weight 77.45 ± 2.4 kg. Three grams of taurine and 400 ml of chocolate milk (TAUchoc), or a placebo (chocolate milk) (CHOC) was ingested post exercise for 8 weeks. Oxidative stress marker levels, and 24 h urinary nitrogen, creatinine, and urea excretion were measured before and after 8 weeks of training and supplementation with TAUchoc or CHOC. A maximal incremental running test on a treadmill was performed in order to evaluate aerobic parameters: Vmax, heart rate (HR) and rate of perceived exertion (RPE).Results: TAUchoc treatment during the 8 weeks resulted in increased taurine plasma levels (PRE 201.32 ± 29.03 μmol/L and POST 234.36 ± 35.51 μmol/L, p = 0.01), decreased malondialdehyde levels (19.4%, p = 0.03) and urinary nitrogen excretion (−33%, p = 0.03), and promoted positive nitrogen balance (p = 0.01). There were no changes in reduced glutathione (TAUchoc PRE 0.72 ± 0.08 mmol/L and POST 0.83 ± 0.08 mmol/L; CHOC PRE 0.69 ± 0.08 mmol/L and POST 0.81 ± 0.06 mmol/L), vitamin E plasma levels (TAUchoc PRE 33.99 ± 2.52 μmol/L and 35.95 ± 2.80 μmol/L and CHOC PRE 31.48 ± 2.12 μmol/L and POST 33.77 ± 3.64 μmol/L), or aerobic parameters, which were obtained in the last phase of the maximal incremental running test (Vmax TAUchoc PRE 13 ± 1.4 km/h and POST 13.22 ± 1.34 km/h; CHOC PRE 13.11 ± 2.34 km/h and POST 13.11 ± 2.72 km/h), the heart rate values were TAUchoc PRE 181.89 ± 24.18 bpm and POST 168.89 ± 46.56 bpm; CHOC PRE 181.56 ± 2.14 bpm and POST 179.78 ± 3.4 bpm, and the RPE were TAUchoc PRE 8.33 ± 2.4 AU and POST 9.1 ± 2.1 AU; CHOC PRE 8.11 ± 4.94 AU and POST 8.78 ± 2.78 AU).Conclusion: Taurine supplementation did not improve aerobic parameters, but was effective in increasing taurine plasma levels and decreasing oxidative stress markers, which suggests that taurine may prevent oxidative stress in triathletes.

Serum-derived extracellular vesicles (EVs) impact on vascular remodeling and prevent muscle damage in acute hind limb ischemia

Serum is an abundant and accessible source of circulating extracellular vesicles (EVs). Serum-EV (sEV) pro-angiogenic capability and mechanisms are herein analyzed using an in vitro assay which predicts sEV angiogenic potential in vivo. Effective sEVs (e-sEVs) also improved vascular remodeling and prevented muscle damage in a mouse model of acute hind limb ischemia. e-sEV angiogenic proteomic and transcriptomic analyses show a positive correlation with matrix-metalloproteinase activation and extracellular matrix organization, cytokine and chemokine signaling pathways, Insulin-like Growth Factor and platelet pathways, and Vascular Endothelial Growth Factor signaling. A discrete gene signature, which highlights differences in e-sEV and ineffective-EV biological activity, was identified using gene ontology (GO) functional analysis. An enrichment of genes associated with the Transforming Growth Factor beta 1 (TGFβ1) signaling cascade is associated with e-sEV administration but not with ineffective-EVs. Chromatin immunoprecipitation analysis on the inhibitor of DNA binding I (ID1) promoter region, and the knock-down of small mother against decapentaplegic (SMAD)1–5 proteins confirmed GO functional analyses. This study demonstrates sEV pro-angiogenic activity, validates a simple, sEV pro-angiogenic assay which predicts their biological activity in vivo, and identifies the TGFβ1 cascade as a relevant mediator. We propose serum as a readily available source of EVs for therapeutic purposes.

Dystrophic phenotype improvement in the diaphragm muscle of mdx mice by diacerhein.

Chronic inflammation and oxidative stress are striking features of Duchenne muscular dystrophy disease. Diacerhein is an anthraquinone, which exhibits anti-inflammatory and antioxidant properties. Based on their actions, the present study evaluated the effects of diacerhein against myonecrosis, oxidative stress and inflammatory response in the diaphragm muscle of mdx mice and compared these results to current treatment widely used in DMD patients, with a main focus on the impact of prednisone. The results demonstrated that diacerhein treatment prevented muscle damage indicated by a decrease in the IgG uptake by muscle fibers, lower CK levels in serum, reduction of fibers with central nuclei with a concomitant increase in fibers with peripheral nuclei. It also had an effect on the inflammatory process, decreasing the inflammatory area, macrophage staining and TNF-α and IL-1β content. Regarding oxidative stress, diacerhein treatment was effective in reducing the ROS and lipid peroxidation in the diaphragm muscle from mdx mice. Compared to prednisone treatment, our findings demonstrated that diacerhein treatment improved the dystrophic phenotype in the diaphragm muscle of mdx mice similar to that of glucocorticoid therapy. In this respect, this work suggests that diacerhein has a potential use as an alternative drug in dystrophinopathy treatment and recommends that its anti-inflammatory and antioxidants properties in the dystrophic muscle should be better understood.

Low-Dose Sodium Nitrite Fluid Resuscitation Prevents Lethality From Crush Syndrome by Improving Nitric Oxide Consumption and Preventing Myoglobin Cytotoxicity in Kidney in A Rat Model.

Crush syndrome (CS) is a serious medical condition characterized by muscle cell damage resulting from pressure. CS has a high mortality, even when patients receive fluid therapy. We examined whether administration of NaNO2-containing fluid can improve survival in a rat model of CS. The CS model was generated by subjecting anesthetized rats to bilateral hind limb compression with a rubber tourniquet for 5 h. Rats were then randomly divided into six groups: sham; CS with no treatment; CS with normal saline treatment; CS with normal saline + 25 mEq/L bicarbonate treatment; and CS with normal saline + 200 or 500 μmol/kg NaNO2. Blood and tissue samples were collected for histological and biochemical analyses at predetermined time points before and after reperfusion. Ischemic compression of rat hind limbs reduced nitrite content in the crushed muscle, and subsequent reperfusion resulted in reactive oxygen species-induced circulatory dysfunction and systemic inflammation. Rats treated with 200 μmol/kg NaNO2 showed increased nitric oxide (NO) levels, blood circulation, and neoangiogenesis, decreased generation of reactive oxygen species, and suppression of the inflammatory response, leading to complete recovery. Treatment with 200 μmol/kg NaNO2 prevents muscle damage induced by ischemia reperfusion via the protective effects of NO and suppression of systemic inflammation, thereby increasing survival rates in CS.

Cryotherapy induces an increase in muscle stiffness.

Although cold application (ie, cryotherapy) may be useful to treat sports injuries and to prevent muscle damage, it is unclear whether it has adverse effects on muscle mechanical properties. This study aimed to determine the effect of air-pulsed cryotherapy on muscle stiffness estimated using ultrasound shear wave elastography. Myoelectrical activity, ankle passive torque, shear modulus (an index of stiffness), and muscle temperature of the gastrocnemius medialis were measured before, during an air-pulsed cryotherapy (-30°C) treatment of four sets of 4minutes with 1-minute recovery in between and during a 40minutes postcryotherapy period. Muscle temperature significantly decreased after the second set of treatment (10minutes: 32.3±2.5°C; P<.001), peaked at 29minutes (27.9±2.2°C; P<.001) and remained below baseline values at 60minutes (29.5±2.0°C; P<.001). Shear modulus increased by +11.5±11.8% after the second set (10minutes; P=.011), peaked at 30minutes (+34.7±42.6%; P<.001), and remained elevated until the end of the post-treatment period (+25.4±17.1%; P<.001). These findings provide evidence that cryotherapy induces an increase in muscle stiffness. This acute change in muscle mechanical properties may lower the amount of stretch that the muscle tissue is able to sustain without subsequent injury. This should be considered when using cryotherapy in athletic practice.

Review of the Food Guidelines in Continuous Ultramarathon

The ultramarathon is defined as an event whose distance is greater than a marathon. It requires not only a preparation on the endurance performance, but also of other more specific qualities such as orientation and climbing. This type of event has a minimum duration of 5 h up to 22 consecutive days or more. These characteristics influence in the preponderance of the energy system and consequently which nutrients will be necessary to intake and increase in order to replace them. The adequate nutritional planning is a fundamental tool to optimize the athlete’s performance, replenishing nutrients and electrolytes and reducing fatigue during exercise The aim of the review is to determine dietary guidelines in continuous ultramarathons. The energy, macronutrient, vitamin, and mineral requirements will be increased according to the intensity and duration of the ultramarathon. The energy expenditure ranges from 350-650 kcal/h, determining a negative balance. The role of carbohydrates for its rapid energy replenishment and the role of lipids for multi-day events are distinguished. The recommendation of carbohydrates is 7-12 g/kg in order to achieve muscle glycogen repletion. Protein intake is 1.2-1.7 g/kg to prevent muscle damage and/or used it as an energy source in case of a poor energy supply. Hydration is crucial in prolonged events and especially in warm environments. Once the systematic review of nutritional guidelines in continuous ultra-marathon events has been performed, it has been found that athletes fail to meet nutritional and water recommendations. The cause of this fact is multifactorial (e.g., high energy depletions, inability to carry the totality of food with them, tiredness of the same flavors, hot environmental conditions..), but mainly due to gastrointestinal discomfort and lack of appetite. It is important to provide runners with not only accurate nutritional guidelines, but the correct way to accomplish them to finish the event and to prevent episodes that compromise their health.