Reduce Muscle Damage Research Articles

The Effect of Acute Beetroot Juice Supplementation After Strenuous Physical Activity on Creatine Kinase Levels

Strenuous physical activity can cause muscle damage which is marked by an increase in creatine kinase levels. One of the strategies to prevent muscle damage is to consume antioxidants and anti-inflammatory. Beetroot (Beta vulgaris L.) is known to have antioxidant and anti-inflammatory activity. The aim of this study was to determine the effect of acutely giving beetroot juice on creatine kinase levels after strenuous physical activity. The research sample used 20 trained males. The sample was divided into two groups (Experiment = 10; Placebo = 10). The pre-test was done by checking creatine kinase levels before engaging in strenuous physical activity. After doing strenuous physical activity by running on a treadmill with an intensity of 90-100% for 30 minutes, the experimental group was given 300 ml of beetroot juice (BRJ) every day for 3 days, while the control group was given a placebo drink. Creatine kinase levels were measured immediately, 24 hours, 48 hours, and 72 hours after strenuous physical activity. The results showed that CK levels decreased significantly 24 hours, 48 hours and 72 hours after strenuous physical activity in the BRJ group compared to the placebo group (p <0.05) The conclusion of this study is that giving BRJ acutely after doing strenuous physical activity can reduce creatine kinase levels in trained male athletes. Acute JBR supplementation in this study can help reduce muscle damage due to strenuous physical exercise through nutritional interventions

Cryotherapy on Subjective Sleep Quality, Muscle, and Inflammatory Response in Chinese Middle- and Long-Distance Runners After Muscle Damage.

Qu, C, Wu, Z, Xu, M, Lorenzo, S, Dong, Y, Wang, Z, Qin, F, and Zhao, J. Cryotherapy on subjective sleep quality, muscle, and inflammatory response in Chinese middle- and long-distance runners after muscle damage. J Strength Cond Res 36(10): 2883-2890, 2022-The purpose of this investigation was to explore the effects of cold-water immersion (CWI), contrast-water therapy (CWT), and whole-body cryotherapy (CRY) on subjective sleep quality, muscle damage markers, and inflammatory markers in middle- and long-distance runners after muscle damage. Twelve male runners from Beijing Sport University completed a muscle damage exercise protocol and were treated with different recovery methods (CWI, CWT, CRY, or control [CON]) immediately after exercise and at 24-, 48-, and 72-h postexercise. The Pittsburgh Sleep Quality Index questionnaire score, lactate dehydrogenase (LDH) activity, myoglobin (Mb) activity, interleukin-6 (IL-6) activity, and soluble intercellular adhesion molecule-1 (sICAM-1) activity were measured at 7 time points (preexercise; immediately postexercise; and at 1-, 24-, 48-, 72-, and 96-h postexercise). Pittsburgh Sleep Quality Index scores indicated that the CRY condition had improved sleep quality compared with the CON and CWI conditions (p < 0.05). In terms of LDH activity, the CRY and CWT conditions had improved recovery compared with the CON and CWI conditions (p < 0.05). In terms of Mb activity, the CRY condition exhibited improved recovery compared with that of the CON and CWI conditions (p < 0.05), and the CWT condition showed better recovery than that of the CON condition (p < 0.05). In terms of IL-6 activity, the CRY condition showed improved recovery compared with the CWI condition (p < 0.05). Finally, in terms of sICAM-1 activity, the CRY condition had enhanced recovery compared with the other 3 conditions (p < 0.05). The results from this study suggest that CRY improves subjective sleep quality and reduces muscle damage and inflammatory responses in middle- and long-distance runners. In addition, CWT reduced muscle damage and inflammatory responses, but its effects on the other parameters were inconclusive.

Physical Activity and Oxidative Stress - A Potential Role of L- Carnitine as an Antioxidant: A Review

Regular physical activity, along with a balanced diet, formsan important factor for the maintenance of good health. However, strenuousexerciseincreases the production of free radicals (FR) and reactive oxygen and nitrogen species (RONS), leads to toxicity, resulting in chronic fatigue, injuries. The overproduction of RONS is involved in muscular fatigue, many diseases, and aging. However, FRs are essential for the functioning of the immune system and certain metabolic functions.The increase in oxidants compared to antioxidant leads to oxidative stress. Nowadays, antioxidants are supplemented to reduce muscle damage incurred during exercise, which has drawn the attention of the athletic population. L- Carnitine being ergogenic, acts as an antioxidant during recovery from exercise, thereby attenuate oxidative stress, which may then decrease exercise-induced muscle damage. Despite increasing research on antioxidant properties for carnitine in several pathologies such as diabetes, hypertension, renal, neurodegenerative conditions, and liver disease, less has been documented on it against oxidative stress induced by exercise. This review may help researchers who are interested in athletic performance enhancement and sports nutrition.

Evaluation of the Efficacy of Supplementation with Planox® Lemon Verbena Extract in Improving Oxidative Stress and Muscle Damage: A Randomized Double-Blind Controlled Trial.

Excessive exercise load can cause muscle soreness and fatigue, as well as inflammation and oxidative stress. Lemon verbena (Aloysia triphylla; Lippia citriodora) is often used as a spice in tea or beverages. Its leaves are rich in polyphenols, which have antioxidant and anti-inflammatory bioactivities. In the present study, we investigated whether supplementation with Planox® lemon verbena extract (LVE) could improve muscle damage and biochemical indicators after exhaustive exercise challenge. All subjects (30 males and 30 females) underwent a double-blind trial and were randomly divided into a placebo group (0 mg/human/day) and an LVE supplement group (400 mg/human/day), with gender-equal distribution. All subjects started supplementation 10 days before exhaustive exercise and continued it until all tests were completed. Before the intervention, after the exhaustive exercise, and on the following 3 days, the participants underwent 12-minute Cooper running/walking; blood collection; assessments of pain, muscle stiffness, maximum jump heights, and isometric maximum muscle strength. The results showed that supplementation with LVE effectively increased GPx and reduced CK, IL-6, 8-OHdG and muscle pain after the exhaustive exercise, but it had significant effect on strength recovery. In summary, LVE is a safe and edible natural plant extract that can reduce muscle damage and soreness after exercise. This trial was registered at clinicaltrials.gov as NCT04742244.

Hemiarthroplasty of the hip using the direct anterior approach.

ObjectiveMinimally invasive approach in total hip arthroplasty for the treatment of femoral neck fractures with a hemiarthroplasty.IndicationsFemoral neck fractures of patients without hip osteoarthritis where the acetabulum is still intact.ContraindicationsLesions and infections of the skin in the approach area; hip osteoarthritis; surgeon’s lack of experience with the technique.Surgical techniqueThe direct anterior approach (DAA) uses the Smith–Peterson interval between the tensor fasciae latae (TFL) and the rectus and sartorius muscle. After coagulation of the ascending branches of the femoral circumflex vessels, the capsule is opened. The remaining parts of the femoral neck are removed and osteotomized if necessary. The femoral head is removed with a cork screw. Then the shaft is supported by 2 sharp retractors at the greater trochanter from cranial, and the leg is externally rotated, hyperextended, and adducted. A TFL release can be performed which we also recommend. The femoral canal is opened step by step and extended with rasps which are introduced with the double curved broach handle. Cement and the final implant are introduced and after the trial reduction also the final head. The hip is reduced, the capsule adapted and the wound closed.Postoperative managementFor this approach, there are no approach specific recommendations. Postoperative treatment depends on whether the approach was extended with muscle releases and on the type of reconstruction performed. If the approach was limited to the minimally invasive direct anterior portal, quicker rehabilitation can be expected due to the reduced muscle damage. We prefer mobilization with full weight bearing as tolerated on the next day.

Effect of Mat Pilates on Body Fluid Composition, Pelvic Stabilization, and Muscle Damage during Pregnancy

In this study, according to the exercise intensity (50–60% of HRmax (Maximum Heart Rate), RPE (Rating of Perceived Exertion: 11–13) proposed by The American Congress of Obstetricians and Gynecologists (ACOG) for pregnant women, mat Pilates exercise is related to body composition, lipid parameters, and pelvic stabilization. The effects on muscle and muscle damage were investigated. The subjects of this study were 16 pregnant women registered at the Cultural Center of Gyeonggi-do C Women’s Hospital, and the gestation period was 16 to 24 weeks. The mat Pilates exercise program (twice a week, 60 min per day, total 12 weeks) changed the Pilates exercise program every 6 weeks according to the subject’s pain level and physical fitness. Body composition before and after exercise, hip flexion, abduction and dilated lipids, inflammation, muscle damage, and stress hormones were measured through blood biochemical analysis. First, the difference in total body water, intracellular water, and skeletal muscle changes (post-pre) increased significantly in the Pilates exercise (PE) group compared to the control (CON) group, while the extracellular/intracellular water ratio significantly decreased. The effect of Pilates on body composition and lipid profile confirmed that, after testing, total body water (TBW), intracellular water (ICW), and extracellular water (ECW) were significantly greater than pre-test values in both groups (TBW: z = −2.286, p = 0.022, r = 0.572; ICW: z = −2.818, p = 0.005, r = 0.705; ECW: z = −1.232, p = 0.218, r = 0.308), whereas the ECW/ICW ratio decreased significantly only in the PE group (z = −2.170, p = 0.030, r = 0.543); while the increases in TBW and ICW were greater in the PE group than in the CON group, the ECW/ICW ratio decreased significantly in the PE group. Blood tests showed significant increases in body weight (BW), body fat mass (BFM), and percentage of body fat (PBF) in both groups post-test as compared to pre-test (BW: z = −1.590, p = 0.112, r = 0.398; BFM: z = −0.106, p = 0.916; PBF: z = −1.643, p = 0.100, r = 0.411). There was a slight increase in creatine kinase (CK) and lactate dehydrogenase (LDH), which are indices of muscle damage, and in the difference between the periods within the group, the CK and LDH of the CON group showed a tendency to increase significantly after inspection compared to the previous values (CK: z = −1.700, p = 0.089, r = 0.425, LDH: z = −2.603, p = 0.009, r = 0.651). Aspartate aminotransferase (AST) decreased significantly in the Pilates exercise group compared to that in the control group, and as a result of confirming the difference in the amount of change in C-reactive protein (CRP), there was no significant difference between the two groups, and the PE group showed a tendency to decrease after inspection compared to the previous period even in the difference between the periods in the group. The CON group showed an increasing trend, but no significant difference was found. Cortisol, a stress hormone, also increased significantly after inspection both groups compared to before (CON group: z = −2.201, p = 0.028; PE group: z = −2.547, p = 0.011). Therefore, the 12 week Pilates exercise program conducted in this study has a positive effect on body water balance and strengthens the muscles related to pelvic stabilization within the range of reducing muscle damage or causing muscle damage and stress in pregnant women. We think that it has an effective exercise intensity.

The effects of concentric and eccentric training in murine models of dysferlin-associated muscular dystrophy.

Dysferlin-deficient murine muscle sustains severe damage after repeated eccentric contractions. With a robotic dynamometer, we studied the response of dysferlin-sufficient and dysferlin-deficient mice to 12 weeks of concentrically or eccentrically biased contractions. We also studied whether concentric contractions before or after eccentric contractions reduced muscle damage in dysferlin-deficient mice. After 12 weeks of concentric training, there was no net gain in contractile force in dysferlin-sufficient or dysferlin-deficient mice, whereas eccentric training produced a net gain in force in both mouse strains. However, eccentric training induced more muscle damage in dysferlin-deficient vs dysferlin-sufficient mice. Although concentric training produced minimal muscle damage in dysferlin-deficient mice, it still led to a prominent increase in centrally nucleated fibers. Previous exposure to concentric contractions conferred slight protection on dysferlin-deficient muscle against damage from subsequent injurious eccentric contractions. Concentric contractions may help dysferlin-deficient muscle derive the benefits of exercise without inducing damage.

Effect of Ibuprofen on Muscle, Hematological and Renal Function, Hydric Balance, Pain, and Performance During Intense Long-Distance Running.

de Souza, RF, de Matos, DG, Ferreira, ARP, Chilibeck, P, Barros, NdA, de Oliveira, AS, Cercato, LM, da Silva, DS, and Aidar, FJ. Effect of ibuprofen on muscle, hematological and renal function, hydric balance, pain, and performance during intense long-distance running. J Strength Cond Res 34(7): 2076-2083, 2020-The aim of this study was to investigate the effect of prophylactic use of nonsteroidal anti-inflammatory drugs (i.e., ibuprofen) on physical performance, vertical jump, muscle biomarkers, liver, kidney, acute pain, and hydration status of participants in the 42-km Trail Running Challenge, a long-distance race integrated over mountain routes. The sample consisted of 20 men randomly divided into 2 groups: a control group (CG) and an experimental group (EG), with 12 completing the race (41.1 ± 8.8 years; 75.7 ± 12.1 kg) and included in the final analysis. The EG were administered an ibuprofen capsule (400 mg) 15 minutes before the beginning of the race and again after 5 hours of racing if the route was not yet completed. There were significant time main effects for creatine kinase (p = 0.001; f Cohen = 0.25), lactate dehydrogenase (p < 0.001; f Cohen = 2.05), aspartate aminotransferase (p = 0.002; f Cohen = 1.53), creatinine (p = 0.002; f Cohen = 2.24), urea (p = 0.001; f Cohen = 2.25), heart rate (p < 0.001; f Cohen = 4.88), and pain scores (p < 0.001; f Cohen = 1.93) all of which increased during the race. There was a group × time interaction for squat jump, which significantly decreased only in the CG (p = 0.045; f Cohen = 2.17). This may have been related to increased frequency of pain reported after the race in the gastrocnemius of the CG compared with the EG (p ≤ 0.05). It was concluded that ibuprofen intake did not reduce muscle damage during the competition but maintained leg muscular power performance (i.e., vertical jump), possibly by reducing gastrocnemius muscle pain.

Effects Of Recovery Using Cryotherapy On The Athlete’S Immune System After Repetitive Exhausting Aerobic Exercise

Muscle damage and changes in immune cell numbers are induced by intensive repetitive and long-term physical stress leading to fatigue and decreased performance. It is widely suggested that cryotherapy (CT) is an effective strategy for accelerated recovery. PURPOSE: Assessing the influence of CT compared to passive recovery on blood biomarkers after repetitive and exhausting aerobic running exercise. METHODS: Twelve moderately trained males (age: 28 ± 5.1 yrs) participated in this randomized cross-over study. After a graded exercise test the protocol comprised two visits including four exhaustive runs on a treadmill starting every 60 min with inclines being raised every 4 min. During the rest period of 20 min, participants rested passively or CT was applied using pants with an integrated cooling system (Aquilo Sports GmbH, Switzerland). Heart rate (HR) was measured continuously and venous blood samples were taken before, immediately, 30 min, 1 h, 3 h, and 24 h after terminating the final run. The following parameters were analyzed: blood glucose (GLU), creatine kinase (CK), lactatedehydrogenase (LDH), total white blood cells (WBC), lymphocytes (LYM), granulocytes (GRA), interleukin 6 (IL-6), blood lactate concentration (La). RESULTS: Significant longer running times were found in the final run when using CT compared to passive rest (+ 5.8%, p = 0.036). GLU was significantly higher immediately after the final run and IL-6 was significantly higher 60 min after terminating the final run in CT (GLU + 362.5%, p = 0.006, IL-6 42,2%, p = 0.046). WBC and GRA were significantly higher in CT 180 min after the final run (WBC + 1.4%, p = 0.028, GRA + 13,7%, p = 0.010). No significant differences were found between recovery methods in HR, maximum La, CK, LDH and LYM (all at p > 0.050). CONCLUSIONS: Application of CT significantly elevated the resistence to fatigue of the participants. There is no evidence that this is due to reduced muscle damage as there has not been an effect in CK. According to the elevation of immune cells a higher activation of the immune system is suggested which in turn is counteracting to the frequently observed immune suppression after exhaustive exercise. Increased IL-6 levels can likely be explained by the increase of GRA. This study identified that there is a trend towards a positive effect of CT on the immune system.

Effects of wearing a full body compression garment during recovery from an ultra-trail race

In sport disciplines with high levels of muscle damage such as an ultra-trail competition, full body compression garments (FBCG) may have an ergogenic effect during the recovery process. The aim of the study was to assess the influence of FBCG worn for 24 h immediately after a 107-km ultra-trail on delayed onset muscle soreness (DOMS), muscle damage, inflammatory and renal response. Thirty-two athletes (19 males and 13 females; VO2peak: 54.1 ± 5.2 ml O2/kg/min) participated in the study. The following blood markers were analysed before, immediately after, at 24 and 48 h post-race: lactate dehydrogenase, creatine kinase, C-reactive protein and creatinine. The glomerular filtration rate was also calculated. Delayed onset muscle soreness was evaluated before, immediately after and at 24 h post-race. On arrival at the finishing line, athletes were randomised into one of two recovery groups (FBCG and control group). The results showed that wearing FBCG did not influence the evolution of any of the blood markers up to 48 h after the race (p > .05). However, FBCG group presented a lower increase in posterior leg DOMS (11.0 ± 46.2% vs 112.3 ± 170.4%, p = .03, d = 0.8). Therefore, although FBCG is not useful for reducing muscle damage and inflammatory response after an ultra-trail race, its use may still be recommended as a recovery method to reduce muscle soreness. Trial registration: ClinicalTrials.gov identifier: NCT03990259.

Nutraceutical and pharmaceutical cocktails did not preserve diaphragm muscle function or reduce muscle damage in D2-mdx mice.

What is the central question of this study? We previously demonstrated that quercetin transiently preserved respiratory function in dystrophin-deficient mice. To gain lasting therapeutic benefits, we tested quercetin in combination with nicotinamide riboside, lisinopril and prednisolone in the D2-mdx model. What is the main finding and its importance? We demonstrated that these quercetin-based cocktails did not preserve respiratory or diaphragmatic function or reduce histological damage after 7 months of treatment starting at 4 months of age. Duchenne muscular dystrophy is characterized by the absence of dystrophin protein and causes muscle weakness and muscle injury, culminating in respiratory failure and cardiomyopathy. Quercetin transiently improved respiratory function but failed to maintain long-term therapeutic benefits in mdx mice. In this study, we combined quercetin with nicotinamide riboside (NR), lisinopril and prednisolone to assess the efficacy of quercetin-based cocktails. We hypothesized that quercetin, NR and lisinopril independently would improve respiratory function and decrease diaphragmatic injury and when combined would have additive effects. To address this hypothesis, in vivo respiratory function, in vitro diaphragmatic function and histological injury were assessed in DBA (healthy), D2-mdx (dystrophic) and D2-mdx mice treated with combinations of quercetin, NR and lisinopril from 4 to 11months of age. Respiratory function, assessed using whole-body plethysmography, was largely similar between healthy and dystrophin-deficient mice. Diaphragm specific tension was decreased by ∼50% in dystrophic mice compared with healthy mice (P<0.05), but fatigue resistance was similar between groups. Contractile area was decreased by ∼10% (P<0.05) and fibrotic area increased from 3.5% in healthy diaphragms to 27% (P<0.05) in dystrophic diaphragms. Contrary to expectations, these functional and histological parameters of disease were not offset by any intervention. These data suggest that quercetin, NR and lisinopril, independently and in combination, did not prevent diaphragmatic injury or preserve respiratory function.

What is effective, may be effective, and is not effective for improvement of biochemical markers on muscle damage and inflammation, and muscle recovery? A Systematic Review of PubMed’s Database

Introduction: The Homo sapiens has one of the most amazing characteristic, adaptability. And when adaptability comes to mind, exercising is just by side. Exercising brings many benefits for our body and it is the greater stimulus to trigger musculoskeletal adaptation, starting at mitochondrial level (i.e. biogenesis) to muscular level (i.e. hypertrophy). Mainly when the exercise is of high performance or strenuous, the athlete need a time to recover from fatigue, muscular damage, over-increase of muscular inflammation series of muscle and to prevent overtraining syndrome. Following the concept of “Evidence Based Practice” that is use the best available evidence in clinical decisions, what should be the methods that really have efficacy to prevent or reduce muscle damage, muscle biochemical markers of inflammation and recover? The aim of this article is to search in the PubMed database about what can help our patients/athletes to recover faster, to avoid or to reduce muscle damage and inflammation.

Modulation of Exercise-Induced Muscle Damage, Inflammation, and Oxidative Markers by Curcumin Supplementation in a Physically Active Population: A Systematic Review.

Physical activity, particularly high-intensity eccentric muscle contractions, produces exercise-induced muscle damage (EIMD). The breakdown of muscle fibers and the consequent inflammatory responses derived from EIMD affect exercise performance. Curcumin, a natural polyphenol extracted from turmeric, has been shown to have mainly antioxidant and also anti-inflammatory properties. This effect of curcumin could improve EIMD and exercise performance. The main objective of this systematic review was to critically evaluate the effectiveness of curcumin supplementation on EIMD and inflammatory and oxidative markers in a physically active population. A structured search was carried out following Preferred Reporting Items for Systematic Review and Meta-Analyses (PRISMA) guidelines in the databases SCOPUS, Web of Science (WOS), and Medline (PubMed) from inception to October 2019. The search included original articles with randomized controlled crossover or parallel design in which the intake of curcumin administered before and/or after exercise was compared with an identical placebo situation. No filters were applied to the type of physical exercise performed, the sex or the age of the participants. Of the 301 articles identified in the search, 11 met the established criteria and were included in this systematic review. The methodological quality of the studies was assessed using the McMaster Critical Review Form. The use of curcumin reduces the subjective perception of the intensity of muscle pain; reduces muscle damage through the decrease of creatine kinase (CK); increases muscle performance; has an anti-inflammatory effect by modulating the pro-inflammatory cytokines, such as TNF-α, IL-6, and IL-8; and may have a slight antioxidant effect. In summary, the administration of curcumin at a dose between 150–1500 mg/day before and during exercise, and up until 72 h’ post-exercise, improved performance by reducing EIMD and modulating the inflammation caused by physical activity. In addition, humans appear to be able to tolerate high doses of curcumin without significant side-effects.

Increased maximum muscle strength and reduced muscle damage in elite weightlifters following low-load, high-repetition resistance training

Increased maximum muscle strength and reduced muscle damage in elite weightlifters following low-load, high-repetition resistance training

The effects of betalain-rich concentrate supplementation in attenuating muscle damage following eccentric exercise

Betalains are bioactive pigments that have been shown to reduce muscle damage and enhance recovery from exercise. However, to date, studies have examined the effects of betalains on aerobic exercise alone, and thus, their possible benefits for muscle damage recovery following eccentric exercise is unknown. We, therefore, aimed to examine the effects of a betalain-rich concentrate (BRC) on indices of muscle damage following eccentric exercise. Eleven healthy, recreationally active males were randomly assigned into a treatment group (50 mg of BRC, containing 12.5 mg of betalains, 3 times per day for 3 days) or a control group and performed 30 maximal eccentric contractions of the elbow flexors. Maximal voluntary contraction (MVC), arm circumference (AC), muscle soreness (MS), and range of motion (ROM) were measured before, immediately after, and 24, 48, and 72 hr following eccentric exercise. Creatine kinase (CK) was measured before, 24, 48, and 72 hr following the eccentric exercise. No significant differences or interactions were observed for any of the variables (p = > .05); however, a non-significant trend with a large effect size (p = .07, ηp2 = 0.28) was found for the main effect for MVC. Although we failed to identify any statistically significant differences in any of the variables measured, the large effect size observed for MVC may have practical benefits in the enhancement of skeletal muscle recovery following eccentric exercise.

Protective Effects of Resveratrol Supplementation on Contusion Induced Muscle Injury.

Muscle injuries frequently occur in contact sports events. The current treatment options for soft tissue injuries remain suboptimal and often result in delayed or incomplete recovery of damaged muscles. Resveratrol (RES) is a phenolic phytochemical, well-known for its antioxidant and anti-inflammatory properties. The purpose of this study is to evaluate the potential beneficial effects of RES supplementation on inflammation and regeneration in skeletal muscle after a contusion injury, in comparison to a conventional treatment of nonsteroidal anti-inflammatory drugs (NSAID). After one week of acclimation, forty eight -week-old male ICR mice were randomly divided into the five groups (n=8 per group): 1) normal control (NC), 2) mass-drop injury without any treatment (mass-drop injury, MDI), 3) post-injury NSAID treatment (MDI+ 10mg/kg NSAID), 4) post-injury RES supplementation (MDI+ 25mg/kg/day RES) and 5) post-injury treatment with RES and NSAID (MDI + resveratrol+ NSAID). After muscle contusion injury of the left gastrocnemius muscle, RES or NSAID were orally administered post-injury once a day for 7 days. Results showed that the MDI group had significantly higher serum uric acid (UA), CREA (creatinine), LDH (lactic dehydrogenase) and creatine kinase (CK) than the normal control group. Treatment with resveratrol reduced muscle damage as evidenced by the significantly decreased serum levels of UA, CREA, LDH and CK after contusion-induced muscle injuries in mice. In addition, RES and RES + NSAID groups promoted muscle satellite cell regeneration with increase in desmin protein after injury. Our results suggest that resveratrol combined with NSAID potentially improve muscle recovery and may be a potential candidate for further development as an effective clinical treatment for muscle repair.

Negligible Effects of β-Hydroxy-β-Methylbutyrate Free Acid and Calcium Salt on Strength and Hypertrophic Responses to Resistance Training: A Randomized, Placebo-Controlled Study.

This study evaluated the effects of β-hydroxy-β-methylbutyrate free acid (HMB-FA) and calcium salt (HMB-Ca) on strength, hypertrophy, and markers of muscle damage. In this randomized, double-blind, placebo-controlled study, 44 resistance-trained men (age: 26 ± 4 years; body mass: 84.9 ± 12.0kg) consuming ≥1.7g·kg-1·day-1 of protein received HMB-FA (3g/day; n = 14), HMB-Ca (3g/day; n = 15), or placebo (PL; cornstarch, 3g/day; n = 15) for 12 weeks, while performing a periodized resistance training program. Before and after intervention, lean body mass (measured with dual X-ray absorptiometry), maximal dynamic strength (one-repetition maximum), knee extension maximal isometric strength (maximal voluntary isometric contraction [MVIC]), cross-sectional area (measured with ultrasound), and muscle soreness were assessed. MVIC was also measured 48hr after the first and the last training sessions. All groups increased lean body mass (main time effect: p < .0001; HMB-FA: 1.8 ± 1.8kg; HMB-Ca: 0.8 ± 1.4kg; PL: 0.9 ± 1.4kg), cross-sectional area (main time effect: p < .0001; HMB-FA: 6.6 ± 3.8%; HMB-Ca: 4.7 ± 4.4%; PL: 6.9 ± 3.8%), one-repetition maximum bench press (main time effect: p < .0001; HMB-FA: 14.8 ± 8.4kg; HMB-Ca: 11.8 ± 7.4kg; PL: 11.2 ± 6.6kg), MVIC (main time effect: p < .0001; HMB-FA: 34.4 ± 39.3%; HMB-Ca: 32.3 ± 27.4%; PL: 17.7 ± 20.9%) after the intervention, but no differences between groups were shown. HMB-FA group showed greater leg press strength after the intervention than HMB-Ca and PL groups (Group × Time interaction: p < .05; HMB-FA: 47.7 ± 31.2kg; HMB-Ca: 43.8 ± 31.7kg; PL: 30.2 ± 20.9kg). MVIC measured 48hr after the first and the last sessions showed no attenuation of force decline with supplementation. Muscle soreness following the first and last sessions was not different between groups. The authors concluded that neither HMB-Ca nor HMB-FA improved hypertrophy or reduced muscle damage in resistance-trained men undergoing resistance training ingesting optimal amounts of protein. HMB-FA but not HMB-Ca resulted in a statistically significant yet minor improvement on leg press one-repetition maximum.

Effect of Curcumin Supplementation on Exercise-Induced Oxidative Stress, Inflammation, Muscle Damage, and Muscle Soreness

Curcumin has been shown to reduce exercise-induced oxidative stress (OS) and inflammation. The purpose of this investigation was to examine the effects of curcumin supplementation on OS, inflammation, muscle damage, and muscle soreness. Nineteen males participated in a randomized, double-blinded, placebo-controlled trial to examine the effects of curcumin supplementation (1.5 g/day) compared to a placebo (PLA) following a muscle-damaging protocol (MDP) on OS, inflammation, muscle damage, and soreness. Participants were randomized to two groups, curcumin or placebo group. The MDP was performed before and after supplementation (28 days). Blood was sampled pre- and postexercise and 60 min, 24 h, and 48 h postexercise and analyzed for total antioxidant capacity (TAC), malondialdehyde (MDA), tumor necrosis factor alpha (TNF-α), and creatine kinase (CK). In addition, a visual analog scale (VAS) was used on each blood sample to measure perceived muscle soreness. After supplementation, curcumin significantly blunted CK levels (199.62 U/L) compared to the placebo (287.03 U/L), overall (p < 0.0001). In addition, curcumin resulted in decreased muscle soreness, overall (VAS scale 2.88), when compared to the placebo (VAS scale 3.36) (p = 0.0120). There were no differences found in TAC, TNF-α, or MDA. Curcumin may reduce muscle damage and perceived muscle soreness without negatively impacting a natural inflammatory response following exercise. Future research should investigate chronic curcumin supplementation and its mechanistic effects on muscle recovery from exercise.

Effects of PDE5 inhibition on dystrophic muscle following an acute bout of downhill running and endurance training.

Lack of sarcolemma-localized neuronal nitric oxide synthase mu (nNOSμ) contributes to muscle damage and fatigue in dystrophic muscle. In this study, we examined the effects of compensating for lack of nNOSμ with a phosphodiesterase type 5 (PDE5) inhibitor in mdx mice following downhill running and endurance training. Dystrophic mice (mdx) were treated with sildenafil citrate and compared with untreated mdx and wild-type mice after an acute bout of downhill running and during a progressive low-intensity treadmill running program (5 days/wk, 4 wk). Magnetic resonance imaging (MRI) and spectroscopy (MRS) transverse relaxation time constant (T2) of hindlimb and forelimb muscles were measured as a marker of muscle damage after downhill running and throughout training. The MRI blood oxygenation level dependence (BOLD) response and 31phosphorus MRS (31P-MRS) data were acquired after stimulated muscle contractions. After downhill running, the increase in T2 was attenuated (P < 0.05) in treated mdx and wild-type mice compared with untreated mdx. During training, resting T2 values did not change in wild-type and mdx mice from baseline values; however, the running distance completed during training was greater (P < 0.05) in treated mdx (>90% of target distance) and wild-type (100%) than untreated mdx (60%). The post-contractile BOLD response was greater (P < 0.05) in treated mdx that trained than untreated mdx, with no differences in muscle oxidative capacity, as measured by 31P-MRS. Our findings indicate that PDE5 inhibition reduces muscle damage after a single bout of downhill running and improves performance during endurance training in dystrophic mice, possibly because of enhanced microvascular function. NEW & NOTEWORTHY This study examined the combined effects of PDE5 inhibition and exercise in dystrophic muscle using high-resolution magnetic resonance imaging and spectroscopy. Our findings demonstrated that sildenafil citrate reduces muscle damage after a single bout of downhill running, improves endurance-training performance, and enhances microvascular function in dystrophic muscle. Collectively, the results support the combination of exercise and PDE5 inhibition as a therapeutic approach in muscular dystrophies lacking nNOSμ.

Effects of concomitant high-intensity interval training and sprint interval training on exercise capacity and response to exercise- induced muscle damage in mountain bike cyclists with different training backgrounds

BACKGROUND: While interval training is considered an effective modality for improving performance, its effectiveness among athletes may be influenced by previous training experience. OBJECTIVE: To investigate whether differences in training background are reflected in the development of exercise ca pacity and level of muscle damage following a single bout of repeated maximal sprints after an 8-week intervention of high-intensity interval training (HIIT), sprint interval training (SIT), and endurance training (ET). METHODS: Three groups of male cyclists were studied: E1 (n= 10) included cyclists with a background in high-volume moderate-intensity training, E2 (n= 7) comprised cyclists with low-volume high-intensity training experience, and C (n= 7) served as a control group with an identical training background as E1. During 8-week intervention HIIT, SIT, and ET were performed by cyclists in group E1 and E2, group C performed only ET. At pre- and post-intervention, cyclists performed two exercise tests: 1) incremental testing protocol (ITP) to assess maximal oxygen uptake (VO2max) and maximal power (Pmax); and 2) sprint interval testing protocol (SITP) to determine oxygen uptake (VO)2, work, and change in creatine kinase (ΔCK) and myoglobin (ΔMb) levels. RESULTS: After intervention, VO2max increased in E1 and E2 group although Pmax increased only in E1. During post-intervention sprint interval testing protocol, VO2 and work increased only in E1, whereas ΔCK and ΔMb decreased in E1 but increased in E2. CONCLUSIONS: A history of high-volume moderate-intensity training can induce beneficial performance adaptations by reducing muscle damage and allowing greater work output. It is suggested that interval training be preceded by a longer period of high-volume training in athletes.