Plasma Creatine Kinase Concentrations Research Articles

The Impact of Carbohydrate, Protein, and Combined Carbohydrate-Protein Supplementation on Muscle Damage and Oxidative Stress Markers During Prolonged Cycling Performance in the Heat

Background: The impact of oxidative stress (OS) on exercise performance and recovery depends on the mode, intensity, and duration of physical activity, which can lead to inflammation, fatigue, and muscle dysfunction. The effects of carbohydrate (CHO) and protein (PRO) supplementation, as well as their combination (CHO-PRO), on exercise performance remain controversial, particularly under normal and hot environmental conditions. Objectives: The present study examined the influence of locally based isocaloric carbohydrate (CHO) and protein (PRO) supplements on muscle damage and oxidative stress (OS) biomarkers during cycling in the heat (31°C, 70% relative humidity), compared to a placebo (PL). Methods: Sago (Sa), Soy (So), and Sago+Soy (SS) were used as the carbohydrate (CHO), protein (PRO), and CHO-PRO supplements, respectively. The Sa, So, and SS supplements contained 7.5% Sa, 7.5% So, and 6.0% Sa+1.5% So, respectively. Twelve well-trained male cyclists (age: 19.0 ± 5.6 years, height: 170.8 ± 7.6 cm, body weight: 60.1 ± 11.2 kg, and VO2max: 56.5 ± 6.5 mL·kg⁻¹·min⁻¹) participated in four experimental trials. Each trial involved 90 minutes of steady-state cycling on an ergometer at 60% VO2max, followed by a 20-km exhaustive cycling time-trial performance. During the steady-state cycling, participants received supplements five times at 0, 20, 40, 60, and 80 minutes. Results: Plasma concentrations of creatine kinase and F2-isoprostanes, which are biomarkers of muscle damage and oxidative stress (OS), significantly decreased after the trials (P < 0.05). The reduction in these biomarkers in the placebo group indicated that Sa, So, and SS supplementation did not provide additional benefits, as the placebo exhibited similar effects. Conclusions: In conclusion, despite the unexpected results, endurance athletes exercising in hot and humid conditions may potentially reduce symptoms of muscle damage and oxidative stress by consuming greater amounts of carbohydrate and protein supplements.

Combined Turmeric, Vitamin C, and Vitamin D Ready-to-Drink Supplements Reduce Upper Respiratory Illness Symptoms and Gastrointestinal Discomfort in Elite Male Football Players.

Elite football is associated with the increased risk of illness, although targeted supplementation can reduce illness risk. This study assessed the effects of a supplement containing turmeric root within a black pepper and fat-soluble blend, vitamin C and vitamin D, on upper respiratory symptoms (URS), gastrointestinal symptoms (GIS), muscle soreness, and markers of inflammation and gut permeability in elite male footballers. Twenty-three footballers completed 3 weeks of no intervention (CON), followed by 16 weeks of daily consuming 60 mL of a commercially available supplement containing raw turmeric root (17.5 g, estimated to contain 700 mg of curcumin), vitamin C (1000 mg), and vitamin D3 (3000 IU/75 mcg) (SUP). URS and GIS were measured daily. Immediately (0 h), 40, and 64 h after six competitive matches (two in CON, four in SUP), the subjective soreness and plasma concentrations of creatine kinase [CK], c-reactive protein [CRP], and intestinal fatty-acid binding protein [I-FABP] were assessed. URS incidence (p < 0.001), GIS (p < 0.05), and plasma [I-FABP] at 0 h (p < 0.05) were greater during CON versus SUP. At 40 h, [CRP] was greater than 0 h during CON (p < 0.01) but not SUP (p = 0.204). There were no differences in soreness or [CK]. This study indicates that turmeric root, vitamin C, and vitamin D supplementation over 16 weeks can reduce URS, GIS, and post-match [I-FABP] in elite footballers.

Chronic almond nut snacking alleviates perceived muscle soreness following downhill running but does not improve indices of cardiometabolic health in mildly overweight, middle-aged, adults.

As a popular food snack rich in protein, fiber, unsaturated fatty acids, antioxidants and phytonutrients, almond nut consumption is widely associated with improvements in cardiometabolic health. However, limited data exists regarding the role of almond consumption in improving exercise recovery. Accordingly, we aimed to investigate the impact of chronic almond snacking on muscle damage and cardiometabolic health outcomes during acute eccentric exercise recovery in mildly overweight, middle-aged, adults. Using a randomized cross-over design, 25 mildly overweight (BMI: 25.8 ± 3.6 kg/m2), middle-aged (35.1 ± 4.7 y) males (n = 11) and females (n = 14) performed a 30-min downhill treadmill run after 8-weeks of consuming either 57 g/day of whole almonds (ALMOND) or an isocaloric amount (86 g/day) of unsalted pretzels (CONTROL). Muscle soreness (visual analogue scale), muscle function (vertical jump and maximal isokinetic torque) and blood markers of muscle damage (creatine kinase (CK) concentration) and inflammation (c-reactive protein concentration) were measured pre and post (24, 48, and 72 h) exercise. Blood biomarkers of cardiometabolic health (total cholesterol, triglycerides, HDL cholesterol, and LDL cholesterol), body composition and psycho-social assessments of mood (POMS-2 inventory), appetite and well-being were measured pre and post intervention. Downhill running successfully elicited muscle damage, as evidenced by a significant increase in plasma CK concentration, increased perception of muscle soreness, and impaired vertical jump performance (all p < 0.05) during acute recovery. No effect of trial order was observed for any outcome measurement. However, expressed as AUC over the cumulative 72 h recovery period, muscle soreness measured during a physical task (vertical jump) was reduced by ~24% in ALMOND vs. CONTROL (p < 0.05) and translated to an improved maintenance of vertical jump performance (p < 0.05). However, ALMOND did not ameliorate the CK response to exercise or isokinetic torque during leg extension and leg flexion (p > 0.05). No pre-post intervention changes in assessments of cardiometabolic health, body composition, mood state or appetite were observed in ALMOND or CONTROL (all p > 0.05). Chronic almond supplementation alleviates task-specific perceived feelings of muscle soreness during acute recovery from muscle damaging exercise, resulting in the better maintenance of muscle functional capacity. These data suggest that almonds represent a functional food snack to improve exercise tolerance in mildly overweight, middle-aged adults.

Relationship between perceived fatigability and the values of biological and biometric markers in young professional and amateur rugby players during a sporting season

Objectives: The aim of our study was to investigate the relationship between the level of perceived fatigability and the values of biological and biometric markers in young professional and amateur rugby players during a sporting season.Materials and methods: The study was conducted on 30 rugby players divided into an amateur (12) and a professional (18) group. Fat mass, creatine kinase and aspartate aminotransferase were measured for 9 months in each player before they completed the french society of exercise and sports medicine overtraining questionnaire. Statistical analysis was performed and the significance level was set at 5%.Results: The higher the percentage of body fat the athletes have, the higher the questionnaire score (r= 0.14, p &lt; 0.01). Plasma creatine kinase and aspartate aminotransferase concentrations were negatively correlated with overtraining score (creatine kinase: r= -0.15, p= 0.03; aspartate aminotransferase: r= -0.11, p= 0.03).Conclusion: Our study has shown that there is a negative correlation between our biological markers and the perceived fatigue score and a positive correlation between body fat and the same score. Further work is required to determine whether creatine kinase, aspartate aminotransferase and percentage of body fat can really be markers of fatigue or even markers of recovery (creatine kinase) in order to make the best use of them in the monitoring of rugby players.

COMPARATIVE STUDY ON THE IMPACT OF DIFFERENT IMMOBILIZATION METHODS ON MUSCLE INTEGRITY AND STRESS INDICATORS IN BROOK TROUT (SALVELINUS FONTINALIS).

Chemical sedation of fish is often used during scientific research to reduce stress and risk of injury. Electric fish handling gloves (EFHG) have been proposed as a no-residue alternative to chemical immobilization. However, the impact of handling fish with EFHG on their physiology remains relatively poorly studied. Stress markers (plasma cortisol and lactate) and the impact on muscular integrity (plasma creatine kinase and histopathology of skeletal muscles) were assessed in brook trout (Salvelinus fontinalis) subjected to one of three immobilization methods (manual restraint, EFHG [10-16 mV], and buffered 60 mg/L tricaine methanesulfonate [MS-222] immersion anesthesia) for 1- and 5-min restraints. Plasma lactate levels were significantly higher 2 h postrestraint for all experimental groups (+242%; P < 0.001), but the magnitude of these increases was significantly lower in the MS-222 groups (P ≤ 0.0002). Plasma creatine kinase concentrations significantly increased 2 h postrestraint for the EFHG groups (+92%, P ≤ 0.0061), and this increase was significantly higher than in the MS-222 group for the 1-min restraint (P = 0.0031). Although there was no significant difference between the restraining methods tested at all time points for plasma cortisol, the EFHG and manual restraint groups showed a linear and statistically significant increase after the initial 5-min restraint, whereas all other groups presented an expected bell-shaped profile with a plasma peak 1 h after the initial restraint. One fish in the manual restraint group died during the 5-min restraint, and two fish from the EFHG group were euthanized at the end of this protocol because of buoyancy anomalies. All other fish from the 5-min restraint group developed cutaneous saprolegniasis 3 wk after the experiments. The evaluation of the safety of EFHG in brook trout showed similar impacts on the variables tested compared with manual restraint for 1- and 5-min immobilizations.

The effect of time of feeding on plasma amino acids during exercise and recovery in horses.

Feeding management in horses suggests feeding horses in advance of exercise, particularly the grain portion of the diet. Plasma amino acids (AA) peak at 3 to 6 h postfeeding depending on the AA. The timeframe between feeding and exercise may affect the availability of AA during and after exercise. The purpose of this study was to observe the differences in plasma AA in horses fed prior to exercise or after exercise. Eight light type horses were fed a diet with adequate protein and AA for horses in light to moderate exercise. After an adjustment period, horses completed a standardized exercise test (SET). Relative to the SET, horses were fed either 2 h prior (PRE horses) to the SET, 1 h after completing the SET (POST horses), or horses remained fasted throughout the sampling period (FASTED horses). Plasma was drawn prior to exercise, at the peak of exercise as well as at 1, 2, 4, and 7 h postexercise. Plasma was analyzed for AA, glucose, lactate, creatinine, creatine kinase, ammonia, urea-N, and 3-methylhistdine. After completion of the SET and sampling period, horses entered a 1-wk recovery period, which was followed by another SET. The protocol repeated until horses rotated through all feeding protocols in the study (three SETs). The majority of the plasma AA were elevated in PRE horses compared with POST horses prior to the SET until 2 h postexercise where POST horses’ plasma AA concentrations became elevated and remained elevated until the end of the sampling period. In that same time frame, plasma AA for the PRE group decreased out to the end of the sampling period. The elevation of plasma AA in POST horses would be expected as they were fed at 1 h postexercise, whereas PRE horses were reaching a 4 h postfeeding time frame at this point. This elevation was not observed for plasma concentrations of isoleucine, leucine, methionine, and histidine. Concentrations of these AA initially were greater for POST horses in the postexercise period; however, they declined more rapidly than the other AA. The rapid decrease of some of the plasma AA concentrations may suggest uptake by muscle for recovery. This in conjunction with a decrease in plasma creatine kinase concentrations for POST horses suggests that feeding postexercise may facilitate better muscle protein balance (synthesis vs. breakdown) in the recovery period following exercise.

Comparative Study on Electric Fish Handling Gloves and Immersion Anesthesia for the Surgical Implantation of Transmitters in Brook Trout

AbstractAlthough the use of electric fish handling gloves (EFHGs) has been advocated as a no‐residue alternative to chemical immobilization for field studies, the impact of their use on fish welfare remains uncertain for surgical procedures. The effects of EFHGs (10–16 mV), with and without local infiltration of lidocaine (6 mg/kg), on stress and muscle integrity after the surgical implantation of an intracoelomic transmitter in adult Brook Trout Salvelinus fontinalis were compared to the effects of two immersion anesthetics (buffered tricaine methanesulfonate at 60 mg/L and eugenol at 40 mg/L) using blood markers. Lower plane of anesthesia and inconsistent immobilization made surgeries with EFHGs more challenging to perform than surgeries conducted using immersion anesthesia. Plasma cortisol and lactate levels were significantly higher at 1–2 h postprocedure than at the end of the surgery (time 0) for all experimental groups (+210% and +121%, respectively), but no significant differences were detected for the magnitude of these increases between groups. Plasma creatine kinase concentrations significantly increased at 2 h postprocedure for the EFHG treatment groups (+206%), whereas they significantly decreased over the same period for the immersion anesthesia groups (−89%). Residues of lidocaine were not detected in fillets, suggesting the absence of significant systemic diffusion. This study suggests that the use of EFHGs for intracoelomic surgical procedures in Brook Trout induces higher disturbances to muscular physiology compared to immersion anesthesia. Differences in the level of stress, muscular anaerobic activity, or oxidative stress were not documented. Further research is needed to evaluate the analgesic properties of EFHGs and local infiltration with lidocaine.

Biochemical Effects of Routine Gonadectomy on Blood of Domestic Ferrets (Mustela putorius furo).

We studied domestic ferrets (Mustela putorius furo) to evaluate the physiologic effects of routine surgery. Standard plasma biochemistry panels and 1H-NMR spectroscopy of heparinized whole blood were performed on samples taken 24 h prior to and immediately after surgery from female and male ferrets undergoing routine gonadectomy. Increases in plasma glucose, phosphorus, potassium, and creatine kinase concentrations associated with the duration of surgery were identified on plasma biochemistry panels. Whole-blood NMR spectra allowed us to identify 42 metabolites and one drug residue. Variations between pre- and postoperative metabolite concentrations were most pronounced for female ferrets, which underwent more prolonged surgery than males. Affected metabolites included organic acids and osmolytes (betaine, methylmalonate, <small>D</small>-lactate), fatty acids and lipids (2-hydroxy-3-methylbutyric acid), and amino acid groups (acetylglycine, alloisoleucine, leucine, and isoleucine). These findings indicate that 1H-NMR spectroscopy of whole blood provides insight into metabolic perturbations in domestic ferrets undergoing surgery that are not detected in routine clinical chemistry panels.

Nutrient Restriction has Limited Short-Term Effects on Gut, Immunity, and Brain Development in Preterm Pigs

Extrauterine growth restriction (EUGR) in preterm infants is associated with higher morbidity and impaired neurodevelopment. Early nutrition support may prevent EUGR in preterm infants, but it is not known if this improves organ development and brain function in the short and long term. Using pigs as models for infants, we hypothesized that diet-induced EUGR impairs gut, immunity, and brain development in preterm neonates during the first weeks after birth. Forty-four preterm caesarean-delivered pigs (Danish Landrace×Large White×Duroc, birth weight 975±235g, male:female ratio 23:21) from 2 sows were fed increasing volumes [32-180mL/(kg·d)] of dilute bovine milk (EUGR group) or the same diet fortified with powdered bovine colostrum for 19 d (CONT group, 50-100% higher protein and energy intake than the EUGR group). The EUGR pigs showed reduced body growth (-39%, P < 0.01), lower plasma albumin, phosphate, and creatine kinase concentrations (-35 to 14%, P < 0.05), increased cortisol and free iron concentrations (+130 to 700%, P < 0.05), and reduced relative weights of the intestine, liver, and spleen (-38 to 19%, all P < 0.05). The effects of EUGR on gut structure, function, microbiota, and systemic immunity were marginal, although EUGR temporarily increased type 1 helper T cell (Th1) activity (e.g. more blood T cells and higher Th1-related cytokine concentrations on day 8) and reduced colon nutrient fermentation (lower SCFA concentration; -45%, P < 0.01). Further, EUGR pigs showed increased relative brain weights (+19%, P < 0.01), however, memory and learning, as tested in a spatial T-maze, were not affected. Most of the measured organ growth, and digestive, immune, and brain functions showed limited effects of diet-induced EUGR in preterm pigs during the first weeks after birth. Likewise, preterm infants may show remarkable physiological adaptation to deficient nutrient supply during the first weeks of life although early life malnutrition may exert negative consequences later.

Panax ginseng Supplementation Increases Muscle Recruitment, Attenuates Perceived Effort, and Accelerates Muscle Force Recovery After an Eccentric-Based Exercise in Athletes.

Cristina-Souza, G, Santos-Mariano, AC, Lima-Silva, AE, Costa, PL, Domingos, PR, Silva, SF, Abreu, WC, De-Oliveira, FR, and Osiecki, R. Panax Ginseng supplementation increases muscle recruitment, attenuates perceived effort, and accelerates muscle force recovery after an eccentric-based exercise in athletes. J Strength Cond Res 36(4): 991-997, 2022-The effect of Panax ginseng during and after an eccentric-based exercise is underexplored. In this study, we investigated the effect of Panax ginseng on muscle force and muscle excitation during an eccentric-based exercise and on subsequent muscle damage and delayed-onset muscle soreness (DOMS). Using a randomized, double-blind, crossover design, 10 male track and field athletes consumed Panax ginseng or placebo for 8 days. At the fifth day, they performed 4 sets until concentric failure of a half-squat exercise, with eccentric action increased by using an eccentric-inductor device attached to their knees. The rating of perceived exertion (RPE) and vastus lateralis electromyographic (EMG) activity was measured during the half-squat. Plasma lactate dehydrogenase (LDH) and creatine kinase (CK) concentrations, DOMS, and maximal isometric voluntary contractions (MIVCs) with EMG recording were measured at 24, 48, and 72 hours after the half-squat. Panax ginseng attenuated RPE and increased EMG during the sets. The MIVC remained reduced 48 hours after exercise in the placebo but returned to baseline 24 hours after exercise in the Panax ginseng, with values at 24 and 48 hours after exercise significantly higher in the Panax ginseng than in the placebo. The EMG during MIVC was higher in the Panax ginseng than in the placebo over the time points. No significant effect of Panax ginseng on LDH, CK, and DOMS was observed. These findings suggest that Panax ginseng increases muscle excitation and attenuates perceived effort during an eccentric-based exercise as well as accelerates the recovery of muscle force in well-trained athletes.

Effects of essential amino acids supplementation on muscle damage following a heavy-load eccentric training session

Summary Aim Unaccustomed physical exercise, particularly repeated eccentric muscle contractions, induces muscle soreness and alterations on muscle cellular structure. An increase in myofibrillar protein accretion can occur in the early post-exercise period and be potentiated by essential amino acid ingestion. We hypothesized that essential amino acid supplementation could reduce the efflux of indirect markers of muscle damage and delay the onset of muscular soreness in the week following a heavy-load eccentric training session. Methods Twenty-three randomly assigned young males performed a bench press exercise under eccentric condition. They were subdivided into a placebo group (n = 11) and an essential amino acids group (n = 12). The effect of the training session was assessed by analysing two indirect markers of muscle damage, namely plasma concentrations of creatine kinase and myoglobin measured before, immediately after, and post-workout day 1, 2, 3, 4 and 7. Muscle soreness was evaluated by a visual analogy scale at the same time point as the markers of muscle damage. Results The training session induced a significant increase in muscle soreness in both placebo and essential amino acids groups. Plasma creatine kinase release increased significantly at D+3 and D+4 while myoglobin efflux rose at D+3 in placebo group only. No statistical differences were observed between groups for the two indirect markers of muscle damage. Gaussian distribution was found to be the best-fit model for the plasma myoglobine and creatine kinase concentration curves. F-test support that individual curves were statistically distinguishable as comparing to the best-fit values of the three parameters (area, SD and mean) between placebo and essential amino acids group data sets (P Conclusion These data indicate that essential amino acids supplementation do have minor effects on the overall plasma release of indirect markers of muscle damage during the recovery period without impact on delayed-onset muscular soreness.

The effect of night-time exercise on sleep architecture among well-trained male endurance runners.

The aim of the present study was to investigate the effects of night-time (21:00hours) high-intensity, intermittent exercise on sleep architecture among well-trained athletes in a laboratory setting. In a randomized, counterbalanced order, 11 well-trained male runners completed a simulated trail-running exercise (TRAIL) on a motorized treadmill and a resting condition (REST; no exercise during the day). After each condition, nocturnal autonomic nervous system activity and core body temperature (CBT) were measured and sleep was analysed using polysomnography and actigraphy. Markers of muscle damage (maximal voluntary contraction [MVC], plasma creatine kinase concentration [CK] and perceived muscle soreness) were recorded before and immediately (POST), 24hr (H24) and 48hr (H48) after exercise. TRAIL induced a high level of fatigue and mild exercise-induced muscle damage, as determined by a reduction in MVC (-9.4%, p<.01, d=-1.36) and increases in [CK] (+176.0%, p<.01, d=1.49) and perceived muscle soreness (+4.5 UA, p<.01, d=2.17) compared with REST at H24. A trend for increased non-rapid eye movement (+4.2%; p=.10; d=0.86) and reduced rapid eye movement (-4.4%; p=.07; d=-0.87) during sleep was observed for TRAIL compared with the REST condition. Moreover, compared with REST, TRAIL significantly increased CBT and nocturnal HR during the first part of the night. In conclusion, sleep architecture was modified after night-time, high-intensity exercise among well-trained runners.

Pharmacokinetics of tulathromycin following administration to stocker cattle with remote delivery devices.

Remote delivery devices (RDD) are used by some to administer antimicrobials (AM) to cattle when treatment by manual injection is logistically difficult. However, it is not clear that the pharmacokinetics (PK) of AM administered by RDD is comparable to that for AM administered by injection; thus, it is not certain that cattle treated by RDD experience equivalent AM effect. Fifteen crossbred beef steers (body weight [BW] = 302.5 ± 21.7 kg) were used in a three-way crossover study to determine the PK of tulathromycin following administration with RDD in the BQA injection triangle. Cattle were treated by each of three methods at 2.5 mg of tulathromycin per kg of BW with a 60 d washout period between treatments: 1) subcutaneous injection of tulathromycin (SC), 2) treatment by RDD delivered by air pump projector (AIR, Pneudart, Model 178B) at 4.5 m distance, and 3) treatment by RDD delivered by CO2-powered projector at 7.5 m (CO2, Pneudart, Model 176B). Blood was collected prior to injection and at various points up to 552 h post-administration, pharmacokinetic data were analyzed as a mixed model using animal as a random effect and method of administration, order of administration, and their interaction as fixed effects. Plasma creatine kinase (CK) was measured before treatment and at 24 h after treatment to determine the degree of muscle injury resulting from each treatment. Three darts administered by AIR did not discharge (20%; 95% CI = 4% to 48%); and results from these steers were excluded from analysis. Maximum plasma concentration (718, 702.6, and 755.5 µg/mL for SC, AIR, and CO2, respectively) and area under the concentration-time curve (17,885, 17,423, and 18,796 µg • h/mL for SC, AIR and CO, respectively) were similar and not significantly different between methods of administration. There was an effect of time (P = 0.0002), period (P = 0.0001), and interaction between method of administration and study period (P = 0.0210) on plasma concentration of CK. However, method of treatment (P = 0.6091), interaction between method and time (P = 0.6972), interaction between period and time (P = 0.6153), and 3-way interaction between method, period and time (P = 0.6804) were not different. Results suggest that PK of tulathromycin following delivery by RDD can be similar to subcutaneous injection; however, failure of RDD to discharge after delivery by some types of projectors can cause an important proportion of cattle to fail to receive drug as expected.

Lipid emulsion, but not propofol, induces skeletal muscle damage and lipid peroxidation

PurposeProlonged propofol infusion induces skeletal muscle damage. However, it is well known that the lipid emulsion that is the solvent of propofol causes various types of tissue damage via lipid peroxidation, and that propofol, conversely, has an anti-lipid peroxidative effect. The purpose of this study was to determine whether propofol or the lipid emulsion is the cause of muscle damage following prolonged administration.MethodsRats were divided into four groups: NI group (no intervention), Cath group (venous catheter insertion only), Prop group (1% propofol (Maruishi) intravenous infusion at 10 mg/kg/h), and Lipid group (10% Lipofundin® intravenous infusion at 100 mg/kg/h) (n = 10, each group). 1% Propofol (Maruishi) or Lipofundin was infused at 1 mL/kg/h for 72 h. The solvent of 1% propofol (Maruishi) is a 10% lipid emulsion. Lipofundin consists of 50% long-chain triacylglycerols and 50% medium-chain triacylglycerols, similar to the propofol solvent. Plasma concentrations of creatine kinase and myoglobin, superoxide production level, and 4-hydroxynonenal and malondialdehyde expression in the gastrocnemius muscle were evaluated 72 h after the interventions.ResultsPlasma concentrations of creatine kinase and myoglobin in the Lipid group were significantly higher than those in the other three groups. The superoxide production level, and 4-hydroxynonenal and malondialdehyde expression in the Lipid group were also significantly higher than in the other three groups.ConclusionLipofundin induces skeletal muscle damage via lipid peroxidation, and 1% propofol (Maruishi) conversely suppresses the muscle damage via antioxidant effects.

Muscle Damage and Metabolic Responses to Repeated-Sprint Running With and Without Deceleration.

Minahan, CL, Poke, DP, Morrison, J, and Bellinger, PM. Muscle damage and metabolic responses to repeated-sprint running with and without deceleration. J Strength Cond Res 34(12): 3423-3430, 2020-This study aimed to determine whether repeated-sprint running with deceleration aggravates markers of muscle damage or delays the recovery of performance compared with repeated-sprint running without deceleration. Fourteen male team-sport athletes performed 2 randomly ordered testing sessions on a nonmotorized treadmill with one session requiring subjects to decelerate (TMd) within 4 seconds before stopping or immediately step to the side of the treadmill belt at the completion of each sprint (TMa). Peak and mean velocities, speed decrement, blood lactate concentrations, and oxygen uptake were monitored during the repeated-sprint running protocols. Countermovement vertical jump (CMJ) performance, perceived muscle soreness, sit-and-reach flexibility, plasma creatine kinase (CK), lactate dehydrogenase (LDH), and myoglobin (Mb) concentrations were quantified immediately before and after and 45 minutes, 24 and 48 hours after repeated-sprint running protocols. Although muscle damage was indicated by increases in CK, LDH, and Mb (p ≤ 0.05) in both groups, there was no significant effect of condition (TMa vs. TMd) on any of the measured performance or physiological variables (p > 0.05). The present study indicated that the removal of deceleration from repeated-sprint running on a nonmotorized treadmill has no effect on metabolism or performance during or after repeated-sprint running or markers of muscle damage.

Protective Role of Vitamin C Intake on Muscle Damage in Male Adolescents Performing Strenuous Physical Activity.

BACKGROUND:Strenuous non-regular exercise increases reactive oxygen species ROS level leading to an impaired balance between the endogenous antioxidant defence system and the free radicals production. Antioxidants intake can detoxify the peroxides produced during exercise, attenuating the inflammatory responses and therefore may prevent exercise-induced muscle damage.AIM:The purpose of this study was to determine the role of vitamin C intake in attenuating markers of muscle damage, oxidative stress and inflammatory responses in male adolescents performing the non-regular strenuous exercise.MATERIAL AND METHODS:Twenty recreationally active male adolescents were assigned to participate in the study. Eligible subjects performed strenuous recreational exercise (2-3 times per week) were randomly divided into two groups: The vitamin C (VC) group that consumed 500 mg of capsulated vitamin C after breakfast for a period of 90 days and the placebo (PL) group that consumed identical capsules in form and aspect that contained 500 mg of maltodextrin for the same period. Aspartate aminotransferase (AST), creatine kinase (CK), lactate dehydrogenase (LDH) were assessed for muscle damage. Malondialdehyde (MDA) was evaluated as a marker of lipid peroxidation. Plasma creatinine, uric acid and urea were determined to monitor kidney function. C-reactive protein, a marker of systemic inflammation was also measured.RESULTS:In comparison between PL and VC groups, the plasma concentrations of muscle damage markers, oxidative stress markers, kidney function and inflammatory markers showed no significant difference in their baseline values (P > 0.05). The plasma concentrations of CK, LDH, MDA, urea, uric acid and CRP were significantly decreased in the VC group (P < 0.05) as compared to their values before the intake of vitamin C.CONCLUSION:The present results support the intake of vitamin C as an antioxidant for attenuating exercise-induced muscle damage, oxidative stress and inflammatory markers in male adolescents performing the strenuous physical activity.

Time Course of Recovery From Resistance Exercise With Different Set Configurations.

Pareja-Blanco, F, Rodríguez-Rosell, D, Aagaard, P, Sánchez-Medina, L, Ribas-Serna, J, Mora-Custodio, R, Otero-Esquina, C, Yáñez-García, JM, and González-Badillo, JJ. Time course of recovery from resistance exercise with different set configurations. J Strength Cond Res 34(10): 2867-2876, 2020-This study analyzed the response to 10 resistance exercise protocols differing in the number of repetitions performed in each set (R) with respect to the maximum predicted number (P). Ten males performed 10 protocols (R(P): 6(12), 12(12), 5(10), 10(10), 4(8), 8(8), 3(6), 6(6), 2(4), and 4(4)). Three sets with 5-minute interset rests were performed in each protocol in bench press and squat. Mechanical muscle function (countermovement jump height and velocity against a 1 m·s load, V1-load) and biochemical plasma profile (testosterone, cortisol, growth hormone, prolactin, IGF-1, and creatine kinase) were assessed at several time points from 24-hour pre-exercise to 48-hour post-exercise. Protocols to failure, especially those in which the number of repetitions performed was high, resulted in larger reductions in mechanical muscle function, which remained reduced up to 48-hour post-exercise. Protocols to failure also showed greater increments in plasma growth hormone, IGF-1, prolactin, and creatine kinase concentrations. In conclusion, resistance exercise to failure resulted in greater fatigue accumulation and slower rates of neuromuscular recovery, as well as higher hormonal responses and greater muscle damage, especially when the maximal number of repetitions in the set was high.

A randomized controlled trial of manual therapy and pneumatic compression for recovery from prolonged running – an extended study

ABSTRACTManual therapy (MT) and intermittent pneumatic compression (IPC) are recovery methods used by endurance athletes with little evidence supporting effectiveness. This randomized controlled trial evaluated effectiveness of four daily post-race treatments of a specific MT protocol and IPC compared with supine rest on recovery following an ultramarathon among 56 ultramarathoners. Groups were comparable across all characteristics examined, including post-race plasma creatine kinase concentration. Subject completed timed 400 m runs before the race and on days three, five, seven and 14 post- race, and also provided muscle pain and soreness ratings and fatigue scores immediately before and after treatments, and during the 14 days post- race. Daily subjective measures and 400 m run times were not improved by either treatment, but both treatments reduced (p < .05) muscular fatigue scores acutely after treatment following the race and on post-race day 1, and MT improved (p < .05) muscle pain and soreness acutely following the race.

Trimetazidine restores the positive adaptation to exercise training by mitigating statin-induced skeletal muscle injury.

BackgroundExercise rehabilitation is demonstrated to improve the prognosis of patients with coronary heart disease (CHD). Statins, as the key medicine to lower cholesterol in CHD, result in skeletal muscle injury and impair exercise training adaptation. Energy metabolism dysfunction is identified as the potential mechanism underlying statin‐induced skeletal muscle injury. In this study, we investigated the effects of the metabolic modulator trimetazidine on skeletal muscle energy metabolism and statin‐associated exercise intolerance.MethodsHigh‐fat fed apolipoprotein E knockout (ApoE−/−) mice were given aerobic exercise and administrated simvastatin, trimetazidine, or simvastatin plus trimetazidine by gavage. Exercise capacity was evaluated at the end of the treatment by hanging grid test, forelimb grip strength, and running tolerance test. Plasma glucose, lipid, and creatine kinase concentrations were measured at the end of the treatment. After sacrifice, gastrocnemii were stored for assessment of muscle morphology and fibre type. Energy metabolism was estimated by plasma lactic acid concentration, ragged red fibres, and glycogen stores. Activities of mitochondrial complex III, citrate synthase activity, and membrane potential were measured to assess mitochondrial function. Oxidative stress was also evaluated by superoxide in mitochondria, superoxide dismutase activity, and glutathione redox state.ResultsIn high‐fat fed ApoE−/− mice, exercise training had no effect on lipid concentrations. Lower lipid concentrations with increased creatine kinase were observed with additional simvastatin treatment. Exercise capacity increased significantly in response to exercise training alone but was blunted by the addition of simvastatin. Similarly, cross‐sectional area of muscle fibres and the proportion of slow‐twitch fibres increased in the exercise group but decreased in the simvastatin plus exercise group. Additionally, simvastatin increased centronucleated fibres and induced energy metabolism dysfunction by inhibiting complex III activity and thus promoted oxidative stress in gastrocnemius. We demonstrated that trimetazidine could reverse simvastatin‐induced exercise intolerance and muscle damages. We also found the ability of trimetazidine in restoration of muscle fibre hypertrophy and facilitating fast‐to‐slow type shift. The energy metabolism dysfunction and oxidative stress in gastrocnemii were rescued by trimetazidine.ConclusionsTrimetazidine alleviated statin‐related skeletal muscle injury by restoration of oxidative phenotype and increasing fibre cross‐sectional areas in response to exercise training. Correspondingly, the exercise training adaptation were improved in high‐fat fed ApoE−/− mice. Moreover, trimetazidine is able to exert its positive effects without affecting the beneficial lipid‐lowering properties of the statins. Thus, trimetazidine could be prescribed to remedy the undesirable statins‐induced exercise intolerance during cardiac rehabilitation in patients with CHD.

Leukocyte profile, gene expression, acute phase response, and metabolite status of cows with sole hemorrhages

Sole hemorrhages result from disruption to normal claw horn formation and are caused by a variety of internal and external factors. Evidence suggests that they are painful, although they do not usually cause clinical lameness and are difficult to detect by observing cow gait. Little is known about how or whether sole hemorrhages affect the cow systemically. This study compared hematology profile, leukocyte gene expression, and physiological responses of cows with no/mild hemorrhages (category 1; n = 17), moderate hemorrhages (category 2; n = 18), and severe hemorrhages (category 3; n = 12). At approximately 100 d in milk, all cows in the study herd (n = 374) were locomotion scored before hoof examination. The cows included in the study were not clinically lame and had no other hoof disorder. Blood samples were taken from all cows within 24 h of selection. Leukocyte counts were obtained using an automated cell counter, cortisol and dehydroepiandrosterone (DHEA) concentration by ELISA, and plasma haptoglobin, urea, total protein, creatine kinase and glucose were analyzed on a clinical chemistry analyzer. Expression of 16 genes associated with lameness or stress were estimated using real-time quantitative PCR. Data from cows within each category were compared using the Mixed procedure in SAS (version 9.3; SAS Institute Inc., Cary, NC). Fixed effects included hemorrhage severity category and lactation number, with days in milk and body condition score included as covariates. Locomotion score worsened as sole hemorrhage category worsened. Locomotion score of category 1 cows tended to be lower than that of category 2 cows and was lower than that of category 3 cows. The locomotion score of category 3 cows was also greater than that of categories 1 and 2 combined. Category had no effect on leukocyte number, on any of the individual leukocyte cell numbers or percentages, cortisol or DHEA concentration, cortisol:DHEA ratio, or relative expression of any of the genes investigated, and we detected no differences in plasma glucose, protein, or creatine kinase concentrations between categories. However, category 3 cows had greater plasma concentrations of haptoglobin and tended to have lesser concentrations of plasma urea than category 1 and 2 cows. The differences in gait between cows with no or minor sole hemorrhages and cows with severe hemorrhages indicate that hemorrhages may be associated with discomfort or pain. Nevertheless, the only physiological measure that changed with increasing locomotion score was plasma haptoglobin concentration. Haptoglobin has previously been found to be elevated in lame cows, and thus shows promise as a marker for limb pain.