Indicators Of Muscle Damage Research Articles

Effect of Velocity-Based Heavy Resistance Exercise on Exercise-Induced Muscle Damage

<p>目的：探討動作速度流失率達20%即停止的速度依循高強度阻力運動對運動後之血液肌酸激酶 (CK) 活性、肌肉痠痛之視覺類比量表 (VAS) 分數、關節活動角度 (ROM) 與推動槓鈴速度為每秒1公尺的負荷重量 (V1 load) 之動作速度等運動誘發肌肉損傷 (EIMD) 指標之影響。方法：十二位大專男性柔道運動員採交叉、平衡次序的方式，執行3組、負荷為85% 1-RM、反覆至動作速度流失率達20%即停止 (VL20) 與反覆至力竭 (RF) 的臥推與深蹲運動；於運動前、運動後立即、運動後24與48小時量測各項EIMD指標，並紀錄運動執行情形。所測得數據以相依樣本t檢定及重複量數二因子變異數分析比較各項數值之差異。結果：VL20試驗執行第3組深蹲之動作速度流失率顯著低於RF試驗，並在運動後24小時之CK活性即與運動前無顯著差異，而RF試驗在運動後24小時之CK活性仍顯著高於運動後48小時；且VL20試驗在運動後各時間點的VAS分數皆顯著低於RF試驗、運動後24小時臥推V1 load之速度顯著高於RF試驗。結論：執行3組、85% 1-RM、控制動作速度流失率為20%的高強度阻力運動時，在執行深蹲後段會有較小的動作速度流失率，且在運動後立即至運動後48小時都有較低的痠痛感覺；即此方式能降低運動誘發肌肉損傷與加速運動後的恢復。</p> <p> </p><p>Purpose: To investigate the effect of velocity based heavy resistance exercise with 20% velocity loss on plasma creatine kinase (CK) activity, visual analog scale (VAS) of muscle soreness, range of motion (ROM), and against velocity 1 m/s load (V1 load) which commonly used as the indicators of exercise-induced muscle damage (EIMD). Methods: Twelve male collegiate judokas were recruited into the study. Participants performed 3 sets of heavy resistance exercise of bench press and squat at 85% of 1-RM, with the repetitions to 20% velocity loss (VL20) or failure (RF) in a counterbalanced crossover manner. The variables of EIMD and exercise load were measured at the time points of before exercise, immediately after exercise, 24 and 48 hr after exercise. Paired t-test and two-way ANOVA with repeated measurement were used to analyze the variables. Results: The velocity loss for the third set of squats in VL20 trail was significantly lower than in RF trail. The CK activity at 24 hours after exercise in VL20 trail was no significant difference as compared to before exercise. However, the CK activity at 24-hr after exercise in RF trail was significantly higher than 48-hr after exercise. The VAS scores at each time point after exercise in VL20 trail were significantly lower than in RF trail. Moreover, the velocity against the V1 load in bench press at 24-hr after exercise in VL20 trail was significantly higher than in RF trail. Conclusion: Controlling the repetition to 20% velocity loss during heavy resistance exercise for 3 sets of 85% of 1-RM enabled lower velocity loss in squat and lower muscle pain after exercise. It can minimize exercise-induced muscle damage and speed up recovery following resistance training.</p> <p> </p>

CLINICAL APPLICATION OF GENE MEDICINE IN PREVENTING SPORTS INJURIES

ABSTRACT Introduction: Using gene therapy to transfer specific genes to implant therapeutic proteins into damaged tissues is a more promising way to treat sports injuries. The combination of tissue engineering and gene therapy will potentially promote the regeneration and repair of various damaged tissues. Objective: This article explores the adaptive relationship between gene selection therapy and athletes in sports. Methods: We selected students of related majors in sports schools to conduct specific genetic testing and measure the muscle area, fatigue level, muscle damage, and other related indicators before and after exercise. Results: After a series of physical fitness assessments, an increase in the gene sequence, as well as changes in the biochemical indices, were confirmed Conclusions: The muscle gain of the test subject during training is better than other genotypes. Level of evidence II; Therapeutic studies - investigation of treatment results.

Effects of Bilateral and Unilateral Eccentric Exercise on Muscle Damage and Muscular Physiological Indices in Healthy Men

PURPOSE: This study aimed to determine the effects of bilateral and unilateral eccentric exercises on muscle damage and muscular physiological indices in healthy men.METHODS: Using a randomized crossover design, nine adult males without musculoskeletal disorders were divided into a bilateral eccentric exercise group (BEG, n=9) and a unilateral eccentric exercise group (UEG, n=9). Bilateral and unilateral eccentric exercises involved five sets of six repetitions of the rhythm metronome speed eccentric contraction 3 seconds at 110% one repetition maximum (1RM) using bilateral of BEG and the dominant and non-dominant of UEG separated by four weeks, respectively. Muscle damage (flexed and extended ROM, CIR, and VAS) and muscular physiological indices (muscle activity, muscle fatigue, and muscle tone) were measured before, immediately after (0 hour), 24, 48, 72, and 96 hours following bilateral and unilateral eccentric exercises.RESULTS: The flexed ROM, CIR, VAS, muscle activity, and muscle tone were significantly increased after both bilateral and unilateral eccentric exercises (p<.05, respectively). Extended ROM and muscle activity significantly decreased after both bilateral and unilateral eccentric exercises (p<.05, respectively). However, there was no significant interaction between side (S) and time and side (T×S).CONCLUSIONS: These results showed that there was no difference in muscle damage and physiological indices after measuring and setting the 1RM muscle strength separated by bilateral and unilateral eccentric exercises.

Baseline fat fraction is a strong predictor of disease progression in Becker muscular dystrophy.

In Becker muscular dystrophy (BMD), muscle weakness progresses relatively slowly, with a highly variable rate among patients. This complicates clinical trials, as clinically relevant changes are difficult to capture within the typical duration of a trial. Therefore, predictors for disease progression are needed. We assessed if temporal increase of fat fraction (FF) in BMD follows a sigmoidal trajectory and whether fat fraction at baseline (FFbase) could therefore predict FF increase after 2 years (ΔFF). Thereafter, for two different MR‐based parameters, we tested the additional predictive value to FFbase. We used 3‐T Dixon data from the upper and lower leg, and multiecho spin‐echo MRI and 7‐T 31P MRS datasets from the lower leg, acquired in 24 BMD patients (age: 41.4 [SD 12.8] years). We assessed the pattern of increase in FF using mixed‐effects modelling. Subsequently, we tested if indicators of muscle damage like standard deviation in water T2 (stdT2) and the phosphodiester (PDE) over ATP ratio at baseline had additional value to FFbase for predicting ∆FF. The association between FFbase and ΔFF was described by the derivative of a sigmoid function and resulted in a peak ΔFF around 0.45 FFbase (fourth‐order polynomial term: t = 3.7, p < .001). StdT2 and PDE/ATP were not significantly associated with ∆FF if FFbase was included in the model. The relationship between FFbase and ∆FF suggests a sigmoidal trajectory of the increase in FF over time in BMD, similar to that described for Duchenne muscular dystrophy. Our results can be used to identify muscles (or patients) that are in the fast progressing stage of the disease, thereby facilitating the conduct of clinical trials.

The short-term effect of vitamin D supplementation on the response to muscle and liver damages indices by exhaustive aerobic exercise in untrained men: a quasi-experimental study

BackgroundExercise-induced muscle damage typically caused by unaccustomed exercise results in pain, soreness, inflammation, and muscle and liver damages. Antioxidant supplementation might be a useful approach to reduce myocytes and hepatocytes damages. Therefore, the present study was conducted to investigate the effect of short-term vitamin D (Vit D) supplementation on the response to muscle and liver damages indices by Exhaustive Aerobic Exercise (EAE) in untrained men.MethodsIn this clinical trial, 24 untrained men were randomly divided into experimental (Exp; n = 12) and control (C; n = 12) groups. Exp received 2000 IU of Vit D daily for six weeks (42 days), while C daily received a lactose placebo with the same color, shape, and warmth percentage. Two bouts of EAE were performed on a treadmill before and after six weeks of supplementation. Anthropometric characteristics (Bodyweight (BW), height, Body Fat Percentage (BFP), Body Mass Index (BMI), waist to hip ratio (WHR)) were measured at the Pre 1 and Pre 2. Blood samples were taken to measure the Creatine Kinase (CK), Lactate Dehydrogenase (LDH), Aspartate Aminotransferase (AST), Alanine Aminotransferase (ALT), Gamma-Glutamyl Transferase (GGT), Alkaline Phosphatase (ALP), and Vit D levels at four stages: Pre 1 (before the first EE session), Post 1 (after the first EE session), Pre 2 (before the second EE session), and Post 2 (after the second EE session). The data were analyzed using repeated-measures ANOVA, Bonferroni's post hoc test, independent t test, and dependent t-test at the significant level of P < 0.05 using SPSS version 26.ResultsThe results show significant differences between Exp and C in alterations of BW (P = 0.039), BMI (P = 0.025), BFP (P = 0.043), and WHR (P = 0.035). The results showed that EAE increased muscle and liver damage indices and Vit D (P < 0.05). Compared with C, the results of the independent t-test showed significantly lower ALT (P = 0.001; P = 0.001), AST (P = 0.011; P = 0.001), GGT (P = 0.018; P = 0.001), and ALP (P = 0.001; P = 0.001); while significantly higher Vit D (P = 0.001, P = 0.001) in the Exp in both Pre 2 and Post 2; receptivity. The independent t test showed significantly lower ALT (P = 0.001; P = 0.001), AST (P = 0.011; P = 0.001), GGT (P = 0.018; P = 0.001), and ALP (P = 0.001; P = 0.001) and considerably greater Vit D (P = 0.001, P = 0.001) in the Exp in both Pre 2 and Post 2 compared to C. The results of an independent t test showed that LDH and CK levels in the Exp were significantly lower than those in the Post 2 (P = 0.001).ConclusionsShort-term Vit D supplementation could prevent myocytes and hepatocytes damage induced by EAE.

Feasability of An Eccentric Isokinetic Protocol to Induce Trunk Muscle Damage: A Pilot Study.

Eccentric exercise is discussed as a treatment option for clinical populations, but specific responses in terms of muscle damage and systemic inflammation after repeated loading of large muscle groups have not been conclusively characterized. Therefore, this study tested the feasibility of an isokinetic protocol for repeated maximum eccentric loading of the trunk muscles. Nine asymptomatic participants (5 f/4 m; 34±6 yrs; 175±13 cm; 76±17 kg) performed three isokinetic 2-minute all-out trunk strength tests (1x concentric (CON), 2x eccentric (ECC1, ECC2), 2 weeks apart; flexion/extension, 60°/s, ROM 55°). Outcomes were peak torque, torque decline, total work, and indicators of muscle damage and inflammation (over 168 h). Statistics were done using the Friedman test (Dunn’s post-test). For ECC1 and ECC2, peak torque and total work were increased and torque decline reduced compared to CON. Repeated ECC bouts yielded unaltered torque and work outcomes. Muscle damage markers were highest after ECC1 (soreness 48 h, creatine kinase 72 h; p<0.05). Their overall responses (area under the curve) were abolished post-ECC2 compared to post-ECC1 (p<0.05). Interleukin-6 was higher post-ECC1 than CON, and attenuated post-ECC2 (p>0.05). Interleukin-10 and tumor necrosis factor-α were not detectable. All markers showed high inter-individual variability. The protocol was feasible to induce muscle damage indicators after exercising a large muscle group, but the pilot results indicated only weak systemic inflammatory responses in asymptomatic adults.

The efficacy of intermittent pneumatic compression and negative pressure therapy on muscle function, soreness and serum indices of muscle damage: a randomized controlled trial

BackgroundThe study aimed to assess whether intermittent pneumatic compression (IPC) and intermittent negative pressure (INP) would attenuate the muscle damaging effects of eccentric exercise.MethodsForty-five healthy males were recruited. Immediately post, 24 and 48 h post eccentric exercise consisting of 100 drop jumps, volunteers randomly received 30-min sessions of intermittent pneumatic compression (IPC, n = 15) or intermittent negative pressure (INP, n = 15), or sham microcurrent (PT, n = 15). Creatine kinase (CK), lactate dehydrogenase (LDH), isokinetic muscle strength, soreness and active flexion of the knee joint were measured after every therapy session.ResultsNo significant intergroup differences were observed in biochemical or functional measurements. However, there was an increase in muscle soreness (P < 0.05), CK and LDH activity (P < 0.05), and a reduction in muscle strength (P < 0.05) and range of active knee flexion (P < 0.05).ConclusionsThe prescription of IPC and INP did not attenuate the reduction of markers to muscle function or pain perception up to 48 h after muscle damaging exercise. Future research should focus on the potential impact of treatment frequency and duration on muscle recovery.Trial registration The study was retrospectively registered in the Australian New Zealand Clinical Trials Registry (ANZCTR); The trial registration number: ACTRN12621001294842; date of registration: 24/09/2021.

Effect of Daily Oral Lactobacillus plantarum PS128 on Exercise Capacity Recovery after a Half-Marathon

A half-marathon (HM) is a vigorous high-intensity exercise, which could induce lower extremity musculoskeletal injury risks for recreational runners. They usually consume nonsteroidal anti-inflammatory drugs (NSAIDs) in order to shorten their return to play but ignore the side effects, such as peptic ulcers and renal and vascular disorders. Lactobacillus plantarum PS128 (PS128) could improve inflammation and oxidative stress by modulating the gut microbiota, thus potentially improving muscle damage and recovery. However, few studies have addressed the PS128 exercise capacity recovery 96 h after HM. Thus, this study aimed to investigate the effect of PS128 on exercise capacity and physiological adaptation after HM. A double-blind, randomized, placebo-controlled, counterbalanced, crossover trial was used for the experiment. HM was conducted at the beginning and end of the 4-week nutritional supplement administration. Eight recreational runners took two capsules (3 × 1010 CFU/capsule) of PS128 each morning and evening before meals for 4 weeks as the PS128 treatment (LT), or they took two capsules of placebo for 4 weeks as the placebo treatment (PT). In both treatments, an exercise capacity test (lower extremity muscle strength, anaerobic power, lower extremity explosive force, and aerobic capacity) and blood test (muscle fatigue, muscle damage, oxidative stress, and renal injury) were performed before the administration of the nutritional supplement (baseline), 48 h before HM (pre), and 0 h (0 h post), 3 h (3 h post), 24 h (24 h post), 48 h (48 h post), 72 h (72 h post), and 96 h (96 h post) after HM. There was no significant difference in the total duration of HM between PT and LT, but PT was found to be significantly higher than LT at Stage 4 (15,751–21,000 m) of HM (3394 ± 727 s vs. 2778 ± 551 s, p = 0.02). The lower extremity muscle strength measured using an isokinetic dynamometer in PT was significantly lower than that in LT at 72 h after HM. The lower extremity explosive force from the countermovement jump (CMJ) in PT was significantly decreased compared to 24 h prior. There was no significant difference between anaerobic power and aerobic capacity between the two treatments after HM. After HM, LT had lower muscle damage indices, such as myoglobin (3 h post-PT vs. -LT: 190.6 ± 118 ng/mL vs. 91.7 ± 68.6 ng/mL, p < 0.0001) and creatine phosphokinase (24 h post-PT vs. -LT: 875.8 ± 572.3 IU/L vs. 401 ± 295.7 IU/L, p < 0.0001). Blood urea nitrogen recovered in 24 h (24 h pre- vs. post-LT, p > 0.05) and higher superoxide dismutase was found in LT (96 h post-PT vs. -LT: 0.267 ± 0.088 U/mL vs. 0.462 ± 0.122 U/mL, p < 0.0001). In conclusion, PS128 supplementation was associated with an improvement in muscle damage, renal damage, and oxidative stress caused by HM through microbiota modulation and related metabolites but not in exercise capacity.

Effect of Vitamin D Supplementation on Muscle Status in Old Patients Recovering from COVID-19 Infection.

Background and Objectives: Vitamin D, in addition to its effect on mineral homeostasis, plays a key role in muscle metabolism. Vitamin D supplementation is involved in muscle recovery after damage as a consequence of either pathology or after high-intensity exercise. In this context, the aim of this study was to analyze the effect of vitamin D on muscle fitness in elderly patients in the recovery phase after SARS-CoV-2 (COVID-19) infection. Materials and Methods: This pilot study was conducted at the Soria Norte Health Center. The study consisted of a double-blind trial with two groups of men (placebo and vitamin D-supplemented) (n = 15/group). Treatment with vitamin D (cholecalciferol: 2000 IU/day) and placebo was carried out for 6 weeks. Circulating hematological and biochemical parameters (total protein, glucose, vitamin D, urea, uric acid, aspartate aminotransferase/glutamic-oxaloacetic transaminase, alanine aminotransferase/glutamic-pyruvic transaminase, creatine kinase, lactate dehydrogenase, aldolase, gamma-glutamyl transferase and myoglobin) and the hormones cortisol and testosterone were determined. As for respiratory function tests, FEV1 and respiratory flow were also studied. For physical fitness tests, the “six-minute walk test” (6MWT) was used. Results: After vitamin D supplementation, we observed that serum creatine kinase levels returned to optimal values. This change suggests a protective role of vitamin D against muscle catabolism compared to placebo. In terms of physical test results, we observed only slight non-significant improvements, although patients reported feeling better. Conclusions: Vitamin D supplementation produces decreases in indicators of muscle damage, which may ultimately contribute to improving the health status and quality of life of patients who have suffered from COVID-19, during the recovery process.

Alterations in skeletal muscle repair in young adults with type 1 diabetes mellitus.

Though preclinical models of type 1 diabetes (T1D) exhibit impaired muscle regeneration, this has yet to be investigated in humans with T1D. Here, we investigated the impact of damaging exercise (eccentric quadriceps contractions) in 18 physically active young adults with and without T1D. Pre- and postexercise (48 h and 96 h), the participants provided blood samples, vastus lateralis biopsies, and performed maximal voluntary quadriceps contractions (MVCs). Skeletal muscle sarcolemmal integrity, extracellular matrix (ECM) content, and satellite cell (SC) content/proliferation were assessed by immunofluorescence. Transmission electron microscopy was used to quantify ultrastructural damage. MVC was comparable between T1D and controls before exercise. Postexercise, MVC was decreased in both groups, but subjects with T1D exhibited moderately lower strength recovery at both 48 h and 96 h. Serum creatine kinase, an indicator of muscle damage, was moderately higher in participants with T1D at rest and exhibited a small elevation 96 h postexercise. Participants with T1D showed lower SC content at all timepoints and demonstrated a moderate delay in SC proliferation after exercise. A greater number of myofibers exhibited sarcolemmal damage (disrupted dystrophin) and increased ECM (laminin) content in participants with T1D despite no differences between groups in ultrastructural damage as assessed by electron microscopy. Finally, transcriptomic analyses revealed dysregulated gene networks involving RNA translation and mitochondrial respiration, providing potential explanations for previous observations of mitochondrial dysfunction in similar cohorts with T1D. Our findings indicate that skeletal muscle in young adults with moderately controlled T1D is altered after damaging exercise, suggesting that longer recovery times following intense exercise may be necessary.

Protective and Recovery Effects of Resveratrol Supplementation on Exercise Performance and Muscle Damage following Acute Plyometric Exercise

Plyometric exercise (PE) is an effective training method to increase muscle mass and strength. However, excessive or inappropriate conditions might cause exercise-induced muscle damage (EIMD). Resveratrol (RES) is a natural polyphenol plant antitoxin, which improves exercise performance, and exhibits anti-oxidation, anti-inflammatory, and anti-cancer effects. Therefore, this study investigated the effect of RES supplementation on the recovery of muscle damage, inflammation, soreness, muscle power, and anaerobic performance following plyometric-exercise-induced muscle damage (PEIMD). The present study was a double-blind, placebo-controlled research trial. Thirty-six young, untrained males were enrolled into the placebo (n = 12), RES-500 (500 mg RES/day, n = 12), or RES-1000 (1000 mg RES/day, n = 12) group by a jumping height-counterbalanced grouping design. At baseline, to pre-PEIMD, supplements were pre-loaded 7 days before they conducted PEIMD, and the exercise performance, delayed-onset muscle soreness (DOMS) and muscle damage biomarkers were measured over the experimental period at baseline, pre-PEIMD, and post-PEIMD at 2, 24, 48, and 72 h. As a result, we found that, at 72 h post-EIMD, the force peak (FP) and rate of force development (RFD) of the counter movement jump (CMJ) in RES groups showed no significant difference compared to that at baseline but was significantly greater than the placebo group. In the Wingate anaerobic test (WAnT), supplementation in the RES group had a better recovery effect on the relative peak power (RPP), relative mean power (RMP) and fatigue index (FI) (p < 0.05), especially in the high-dose group. For the detection of muscle pain after PEIMD, the RES supplement group was significantly better than the placebo group (p < 0.05). In addition, for muscle damage indexes, such as creatine kinase (CK) and lactate dehydrogenase (LDH), after PEIMD, supplementation with RES could significantly reduce and accelerate recovery (p < 0.05). In addition, the blood biochemical indicators of blood count, liver function, and kidney function showed that RES will not cause adverse risks to the human body. Our results suggest that replenishing RES in advance could effectively reduce muscle pain, increase exercise performance, and decrease muscle damage indicators caused by PEIMD, and the recovery was faster. Therefore, plyometric exercises combined with suitable RES supplementation could be an effective candidate for controlling muscle damage, improving physical adaption, and recovering anaerobic capacity.

Creatine supplementation effect on recovery following exercise-induced muscle damage: A systematic review and meta-analysis of randomized controlled trials.

Exercise-induced muscle damage (EIMD) causes increased soreness, impaired function of muscles, and reductions in muscle force. Accumulating evidence suggests the beneficial effects of creatine on EIMD. Nevertheless, outcomes differ substantially across various articles. The main aim of this meta-analysis was to evaluate the effect of creatine on recovery following EIMD. Medline, Embase, Cochrane Library, Scopus, and Google Scholar were systematically searched up to March 2021. The Cochrane Collaboration tool for examining the risk of bias was applied for assessing the quality of studies. Weighted mean difference (WMD), 95% confidence interval (CI), and random-effects model, were applied for estimating the overall effect. Between studies, heterogeneity was examined using the chi-squared and I2 statistics. Nine studies met the inclusion criteria. Pooled data showed that creatine significantly reduced creatine kinase (CK) concentration overall (WMD = -30.94; 95% CI: -53.19, -8.69; p=.006) and at three follow-up times (48, 72, and 96hr) in comparison with placebo. In contrast, effects were not significant in lactate dehydrogenase (LDH) concentration overall (WMD = -5.99; 95% CI: -14.49, 2.50; p=.167), but creatine supplementation leaded to a significant reduction in LDH concentrations in trials with 48hr measurement of LDH. The current data indicate that creatine consumption is better than rest after diverse forms of damaging and exhaustive exercise or passive recovery. The benefits relate to a decrease in muscle damage indices and improved muscle function because of muscle power loss after exercise. PRACTICAL APPLICATIONS: Creatine supplementation would be effective in reducing the immediate muscle damage that happens <24, 24, 48, 72, and 96hr post-exercise. In the current meta-analysis, the positive effects of creatine could cause a decrease in CK concentration overall. But, due to high heterogeneity and the medium risk of bias for articles, we suggest that these results are taken into account and the facts are interpreted with caution by the readers.

Consumption of New Zealand Blackcurrant Extract Improves Recovery from Exercise-Induced Muscle Damage in Non-Resistance Trained Men and Women: A Double-Blind Randomised Trial.

Background: Blackcurrant is rich in anthocyanins that may protect against exercise-induced muscle damage (EIMD) and facilitate a faster recovery of muscle function. We examined the effects of New Zealand blackcurrant (NZBC) extract on indices of muscle damage and recovery following a bout of strenuous isokinetic resistance exercise. Methods: Using a double-blind, randomised, placebo controlled, parallel design, twenty-seven healthy participants received either a 3 g·day−1 NZBC extract (n = 14) or the placebo (PLA) (n = 13) for 8 days prior to and 4 days following 60 strenuous concentric and eccentric contractions of the biceps brachii muscle on an isokinetic dynamometer. Muscle soreness (using a visual analogue scale), maximal voluntary contraction (MVC), range of motion (ROM) and blood creatine kinase (CK) were assessed before (0 h) and after (24, 48, 72 and 96 h) exercise. Results: Consumption of NZBC extract resulted in faster recovery of baseline MVC (p = 0.04), attenuated muscle soreness at 24 h (NZBC: 21 ± 10 mm vs. PLA: 40 ± 23 mm, p = 0.02) and 48 h (NZBC: 22 ± 17 vs. PLA: 44 ± 26 mm, p = 0.03) and serum CK concentration at 96 h (NZBC: 635 ± 921 UL vs. PLA: 4021 ± 4319 UL, p = 0.04) following EIMD. Conclusions: Consumption of NZBC extract prior to and following a bout of eccentric exercise attenuates muscle damage and improves functional recovery. These findings are of practical importance in recreationally active and potentially athletic populations, who may benefit from accelerated recovery following EIMD.

Capture Myopathy in Avian Species: A Review

Capture myopathy, also known as exertional myopathy or exertional rhabdomyolysis, is a complication of capture that can render an animal unable to stand or walk after a capture event. The disease is commonly iatrogenic and associated with pursuit, capture or handling of avian or mammalian species. Clinical signs in birds include difficulty or inability to walk or stand, sternal recumbency or hock–sitting, ataxia, knuckling of the toes, pain, depression, tachypnea, trembling, and death. Renal signs, including myoglobinuria, are less common in avian species. The pathogenesis is related to extreme exertion resulting in anaerobic metabolism and metabolic acidosis. Typical changes seen on blood work are extreme elevations of CK and AST, indicators of muscle damage. Pathologic lesions seen in birds with capture myopathy are similar to those seen in mammals, however, cardiac and renal lesions are less common than in mammals. Treatment is difficult, prolonged, and often unsuccessful. Treatment components utilized in case reports include fluid therapy, vitamin E and selenium supplementation, anti-inflammatories, physical therapy, and muscle relaxants. Given the low success rate of treatment, careful planning of capture events and minimization of patient stress during handling are crucial in order to avoid capture myopathy and the necessity of treatment.

Correlación del dolor y la temperatura corporal en sujetos con lumbalgia: un estudio preliminar

IntroductionPain management is an important issue in a physiotherapeutic approach. Low back pain is one of the main causes of pain and disability in the world, and therefore we studied it using thermography as an imaging tool for objective evaluation and the visual analogue scale for subjective evaluation. ObjectiveTo describe the correlation between subjects with low back pain (PL) and subjects without low back pain (PS) using the subjective sensation of pain and thermographic values as variables. Material and methodsA correlational study was carried out, evaluating 10 subjects divided into two groups, a group of subjects with low back pain and a group without low back pain. The temperature was recorded in degrees Celsius, using thermograms and marking thermal points to evaluate each area, which was correlated with the pain rating initially established by the subjects. ResultsThe subjects without low back pain did not show abnormal temperature variations, and showed healthy musculature. In contrast, 2 subjects with low back pain showed abnormal thermal variations, an indication of probable muscle damage. The other 3 subjects did not show a relationship between pain and thermographic response. ConclusionsThe pain-thermography relationship showed a negative Pearson correlation for the abdominal region and an extremely low positive correlation for the lumbar region, with a statistical significance index greater than .05 (CI). Therefore, in this study no connection was found between pain index and temperature by muscle region. Infrared thermography proved to be a tool capable of detecting thermal alterations in real time, in potentially injured anatomical areas.

Effects of L-citrulline supplementation on nitric oxide and antioxidant markers after high-intensity interval exercise in young men: a randomized controlled trial.

L-citrulline (L-Cit) is a nonessential amino acid that stimulates nitric oxide (NO) production and improves exercise performance by reducing muscle damage indices; however, the direct benefits of L-Cit on antioxidant markers are unclear. The aim of this study was to examine antioxidant responses to high-intensity interval exercise following acute L-Cit supplementation. Nine young men (21 ± 1 years) participated in a double-blind crossover study in which they received 12 g of L-Cit and placebo (PL) an hour prior to high-intensity interval exercise on two occasions, separated by a seven-day washout period. Blood samples were obtained before (PRE), immediately after (IP), 10 (10P), and 30 min after exercise (30P) from the cubital vein using standard procedures. Serum concentrations of superoxide dismutase (SOD), glutathione peroxidase (GPx), catalase (CAT), and NO metabolites (NOx) were measured. The exercise protocol significantly elevated SOD (p = 0.01) and GPx (p = 0.048) from PRE to 10P in the L-Cit group with greater changes than the PL group. CAT concentrations increased IP (p = 0.014) and remained elevated at 10P (p = 0.03) and 30P (p = 0.015) in both the L-Cit and PL conditions. NOx concentrations increased IP (p = 0.05) in the L-Cit group with greater changes than PL group in PRE to IP, PRE to 10P, and PRE to 30P (p < 0.05). Our data indicate that L-Cit supplementation (single 12 g dose pre-exercise) induces improvements in antioxidant markers following a session of high-intensity interval exercise in young men.

Diffusion tensor imaging indices of acute muscle damage are augmented after exercise in peripheral arterial disease.

Although it is known that peripheral arterial disease (PAD) is associated with chronic myopathies, the acute muscular responses to exercise in this population are less clear. This study used diffusion tensor imaging (DTI) to compare acute exercise-related muscle damage between PAD patients and healthy controls. Eight PAD patients and seven healthy controls performed graded plantar flexion in the bore of a 3T MRI scanner. Exercise began at 2kg and increased by 2kg every 2min until failure, or completion of 10min of exercise. DTI images were acquired from the lower leg pre- and post-exercise, and were analyzed for mean diffusivity, fractional anisotropy (FA), and eigenvalues 1-3 (λ1-3) of the medial gastrocnemius (MG) and tibialis anterior (TA). Results indicated a significant leg by time interaction for mean diffusivity, explained by a significantly greater increase in diffusivity of the MG in the most affected legs of PAD patients (11.1 × 10-4 ± 0.5 × 10-4 mm2/s vs. 12.7 × 10-4 ± 1.2 × 10-4 mm2/s at pre and post, respectively, P = 0.02) compared to healthy control subjects (10.8 × 10-4 ± 0.3 × 10-4 mm2/s vs. 11.2 × 10-4 ± 0.5 × 10-4 mm2/s at pre and post, respectively, P = 1.0). No significant differences were observed for the TA, or λ1-3 (all P ≥ 0.06). Moreover, no reciprocal changes were observed for FA in either group (all P ≥ 0.29). These data suggest that calf muscle diffusivity increases more in PAD patients compared to controls after exercise. These findings are consistent with the notion that acute exercise results in increased muscle damage in PAD.

Blood parameters of young calves at abattoirs are related to distance transported and farm of origin

Nonreplacement dairy calves, or bobby calves, are fasted and transported to abattoirs from as young as 5 d of age in Australia. The aims of this cross-sectional observational study were (1) to assess the welfare status, as measured by blood parameters, of bobby calves in the commercial supply chain after transport and lairage, and (2) to assess whether distance and duration of transport are risk factors for poor bobby calf welfare, as measured by blood parameters. We hypothesized that bobby calves transported greater distances would be more likely to show evidence of compromised welfare, as measured by blood indicators of hydration, energy status, and muscle fatigue or damage. We also hypothesized that there would be a large amount of variability in indicators of energy status between calves from different farms. We analyzed blood samples collected at slaughter over a spring and an autumn calving period from 4,484 Australian bobby calves aged approximately 5 to 14 d old from 3 different states, after transport, fasting, and lairage. Packed cell volume (PCV), plasma glucose, and serum urea, total protein, β-hydroxybutyrate (BHB), and creatine kinase (CK) were measured. Radio frequency identification ear tag data were used to estimate the distance that the calves were transported and to identify the farm of origin. Data were analyzed using linear mixed models, except for BHB, which was analyzed using a Goodman-Kruskal gamma test due to left censoring of the data. Twelve percent of calves showed evidence of anemia (PCV less than 0.23 L/L), and 11% had urea concentrations consistent with dehydration (urea more than 7.7 mmol/L). Thirty-six percent of calves had CK activity above normal resting values, and 1% of calves had CK >2,000 U/L, indicating muscle fatigue or damage. Distance transported had significant effects on all blood variables except urea and BHB. With increasing distance transported, calves were more likely to show evidence of a negative energy balance (low plasma glucose) or dehydration (high PCV or total protein). The estimated effect of distance overall was small, but for calves transported more than 500 km, plasma glucose concentration declined more per kilometer. The calves' farm of origin accounted for a reasonable amount of the random variation between calves for plasma glucose (20%). Our results suggest that longer transport distances may increase the risk of poor calf welfare (dehydration, negative energy balance) after transport, and on-farm calf management (e.g., nutrition, timing of feeding before transport) may affect transported calves' energy status; improving this area could result in better energy availability during fasting.

장시간의 고강도 유산소 운동이 항산화 효소 및 근 손상지표에 미치는 영향

Purpose: The purpose of this study is to investigate the effects of long-term aerobic exercise on muscle damage indicators and antioxidant enzymes by observation of amateur athlete participants. We observed the changes that occurred at rest and immediately after a marathon and triathlon.<BR> Method: The subjects of the study were 8 amateur male marathon runners and 9 amateur triathletes. All participants were in their 30’s and 40’s of age and resided in the city of S. After the marathon runners ran a full race of 42.195 kilometers, two blood samples were taken immediately after the race when their conditions were stable. After the triathletes went through an Olympic course which included 1.5 kilometers of swimming, 40 kilometers of cycling, and 10 kilometers of running, two blood samples were also taken immediately after completion when their conditions were stable. Using the SPSS/PC+Ver. 21.0K program, descriptive statistics (Mean ± Standard Error) of all dependent variables were calculated. A two-way repeated ANOVA was performed to verify the difference between the average of the dependent variables once the homogeneity between the two groups (marathon and triathlon) and between thew to tests (stable and immediately after the race) were confirmed. A paired t-test was performed for the differences of the two tests within the groups, and an independent t-test was performed for the differences between the two groups. The statistical significance level was set to α=.05.<BR> Results: In the marathon group, SOD significantly increased immediately after the race (p<.001). In the triathlon group, SOD significantly increased in the same manner after the race (p<.05). There was no significant difference between the two groups. In both groups, CK and LDHi significantly increased immediately after the races (p<.001), with no significant differences between the groups.<BR> Conclusion: During long-term high-intensity aerobic exercise, marathons and triathlons increase oxidative stress, which can lead to muscle damage. Additionally, the increase of SOD, an antioxidant defense system enzyme, is a response to oxidative stress and appears to prevent the generation of free radicals from exercise.

Neuromuscular fatigue and recovery after strenuous exercise depends on skeletal muscle size and stem cell characteristics

Hamstring muscle injury is highly prevalent in sports involving repeated maximal sprinting. Although neuromuscular fatigue is thought to be a risk factor, the mechanisms underlying the fatigue response to repeated maximal sprints are unclear. Here, we show that repeated maximal sprints induce neuromuscular fatigue accompanied with a prolonged strength loss in hamstring muscles. The immediate hamstring strength loss was linked to both central and peripheral fatigue, while prolonged strength loss was associated with indicators of muscle damage. The kinematic changes immediately after sprinting likely protected fatigued hamstrings from excess elongation stress, while larger hamstring muscle physiological cross-sectional area and lower myoblast:fibroblast ratio appeared to protect against fatigue/damage and improve muscle recovery within the first 48 h after sprinting. We have therefore identified novel mechanisms that likely regulate the fatigue/damage response and initial recovery following repeated maximal sprinting in humans.