Increase In Endurance Performance Research Articles

The Effects of 8-week Acetic Acid Feeding on Endurance Performance and Fat Metabolism in Skeletal Muscle of Mice

PURPOSE:The combined effect of acetic acid supplementation and endurance exercise training on fatty acid metabolism and skeletal muscle functions are not well known. Therefore, the purpose of this study was to investigate the effects of 8-week acetic acid administration with or without endurance exercise training on fatty acid metabolism and skeletal muscle functions using mice.METHODS: Fourty-eight male wild-type ICR mice (10-week old) were randomly divided into 4 groups: sedentary control (Sed+Con), sedentary sodium acetate (Sed+NaAc), exercise control (Exe+Con) and exercise sodium acetate (Exe+NaAc) groups. For acetic acid diet, sodium acetate was incorporated into the chow diet at 5% (w/w). For the exercise training, mice performed 4 days/week of 20 min treadmill running exercise training for 8 weeks. Following 8 weeks of combined treatments of acetic acid and endurance running exercise training, visceral fat mass and skeletal muscle mass, blood parameters, and the markers for fatty acid metabolism were analyzed. The results were analyzed with one-way ANOVA (p<.05) using the SPSS 21 program.RESULTS: Eight weeks of Exe+NaAc treatment significantly increased maximal running time compared with Sed+Con and Exe+Con groups (p<.05). Eight weeks of Exe+NaAc treatment significantly decreased fatty acid synthesis-related FAS (fatty acid synthase) protein levels compared with the Sed+Con group, and increased fatty acid oxidation-related CPT1B (carnitine palmitoyltransferase 1B) protein levels compared with Sed+Con and Sed+NaAc groups (p<.05). This combined treatment of acetic acid and endurance exercise training also increased AMPK activation compared with the Sed+Con and the Sed+NaAc groups (p<.05).CONCLUSIONS: It was concluded that there were synergistic effects of the treatment of 8-week acetic acid supplementation and endurance exercise training on the reductions of body weight and visceral fat mass and an increase in endurance performance.

Caffeine mouth rinse enhances performance, fatigue tolerance and reduces muscle activity during moderate-intensity cycling.

We investigated the effects of caffeine mouth rinse on endurance performance, muscle recruitment (i.e., electromyographic activity of the vastus lateralis and rectus femoris), rating of perceived effort and heart rate. Twelve physically-active healthy men cycled at 80% of their respiratory compensation point until task failure. The participants rinsed their mouths for 10 seconds with placebo (PLA, 25 mL of a solution composed of non-caloric mint essence) or caffeine (CAF, 25 mL of 1.2% of anhydrous caffeine concentration with non-caloric mint essence) every 15 minutes of exercise. Time until exhaustion increased 17% (effect size = 0.70) in CAF compared to PLA (p = 0.04). The wavebands of low-frequency electromyographic activity (EMG) of the vastus lateralis and rectus femoris was lower in CAF group than PLA at 50% of the time until exhaustion (p = 0.04). The global EMG signal was lower in CAF group than PLA at 100% of the time until exhaustion (p = 0.001). The rating of perceived effort pooled was higher in CAF mouth rinse (p = 0.001) than PLA group. No effect was found on the heart rate between the groups (p > 0.05). Caffeine mouth rinse increases endurance performance, rating of perceived effort and decreases muscle activity during a moderate-intensity exercise.

High Intensity Shoulder Exercise Improves Function, Pain And Tendinous Blood Flow In Subacromial Pain Syndrome.

Subacromial pain syndrome (SAPS) defined as pain of non-traumatic origin localized around the acromion, is a debilitating, common and often chronic condition. Among many proposed underlying causes of SAPS, hypoperfusion and hypoxic conditions in and around the tendons may be an intrinsic cause of SAPS. Exercise therapy with low load is the advocated treatment of choice for SAPS. PURPOUSE: To determine if high intensity aerobic interval training (HIIT) of the rotator cuff was feasible, more effective in improving endurance and reducing pain compared to low intensity exercises. Additionally, to examine the response of tendinous microcirculation following the exercise therapy. METHODS: 21 subjects with chronic SAPS randomized to two groups: HIIT (n=13) and control group (CG) (n=8) was tested before and after 8 weeks of exercise therapy. Endurance performance was assessed by an incremental abduction adduction exercise of the arm to exhaustion (TTE). Contrast enhanced ultrasound (CEUS) of the m. supraspinatus and tendon was utilized to indicate tendon blood flow. Limitations in daily life was assessed by the shoulder pain and disability index (SPADI). RESULTS: Endurance in the TTE-test improved by an estimated 233 seconds more on average in HIIT than in CG (p=0.001, 95%CI: 102 to 363), the change was significant in HIIT (p<0.001), no change was seen in CG. The SPADI score was reduced 22 points more on average in HIIT (p=0.017, 95%CI: -40 to -5). The change from pre to post-test was significant in HIIT(p<0.001), but not in the CG. HIIT also experienced less pain during exercise after the intervention compared to CG (p<0.001). CEUS indicated an increase in tendinous blood flow in the HIIT group (p=0.019), no change was observed in CG. CONCLUSIONS: HIIT rotator cuff exercise appear to be a feasible intervention in SAPS, reducing pain and increasing endurance performance more than exercise with low load. CEUS indicate that HIIT may increase tendon microcirculation, thus abating a potential hypoperfused/ hypoxic state underlying the condition.

High-Intensity Shoulder Abduction Exercise in Subacromial Pain Syndrome.

This study aimed to determine if adding high-intensity aerobic interval training (HIIT) of the rotator cuff to usual care was feasible in SAPS and improved shoulder endurance more than usual care alone, as well as to examine the influence on shoulder pain and disability and the response of tendinous microcirculation after HIIT. Twenty-one subjects with chronic SAPS were randomized to two groups: experimental group (EG; n = 13) receiving HIIT in addition to treatment as usual and control group (CG; n = 8) receiving treatment as usual. Before and after 8 wk of exercise therapy, endurance performance was assessed by an incremental abduction exercise of the arm to exhaustion (TTE). Pain and disability was assessed by the shoulder pain and disability index (SPADI). Contrast-enhanced ultrasound of the musculus supraspinatus and tendon was utilized to indicate tendon blood flow. Endurance in the TTE test improved by an estimated 233 s more on average in EG than in CG (P = 0.001; 95% confidence interval, 102 to 363). The SPADI score was reduced 22 points more on average in EG (P = 0.017; 95% confidence interval, -40 to -5). The change from pretest to posttest was significant in EG for both TTE test and SPADI improvement (P < 0.001). EG also experienced less pain during exercise after the intervention compared with CG (P < 0.001). Contrast-enhanced ultrasound indicated an increase in tendinous blood flow in EG (P = 0.019). HIIT rotator cuff exercise seems to be a feasible intervention in SAPS, increasing endurance performance more than usual care alone.

The Physiological Effects of Amino Acids Arginine and Citrulline: Is There a Basis for Development of a Beverage to Promote Endurance Performance? A Narrative Review of Orally Administered Supplements

Nutritional and ergogenic aid supplementation is prevalent within athletic or general fitness populations, and is only continuing to gain momentum. Taken in isolation or as a combination, amino acid (AA) supplementation has the potential to increase endurance performance among other benefits. L-Arginine (L-Arg) and L-Citrulline (L-Cit) are two AAs proposed to increase endothelial nitric oxide (NO) synthesis, with potential additional physiological benefits, and therefore may contribute to enhanced performance outcomes such as increased power output, or time to exhaustion. However, the appropriate dose for promoting physiological and performance benefits of these AAs, and their potential synergistic effects remains to be determined. Therefore, the aim of this review was to evaluate the varied concentrations used in the current literature, assess the effects of L-Arg and L-Cit in combination on physiological responses and endurance performance, and consider if there is a fundamental basis for providing these supplements in the form of a beverage. A total of six studies were considered eligible for the review which utilized a range of 3–8 g of the AA constituents. The findings support the notion that supplementing with a combination of L-Arg and L-Cit may increase NO production, enhance vasodilation, and therefore increase performance capacity in athletes. A beverage as a carrier for the two AAs is worth considering; however, there remains limited research assessing these outcomes across a consistent range of concentrations in order to see their full potential.

Six Sessions of Sprint-Interval Training Did Not Improve Endurance and Neuromuscular Performance in Untrained Men.

Previous research demonstrated that six sessions of cycling sprint-interval training (SIT) within a duration of only 2 weeks can increase endurance performance considerably. Primarily muscular mechanisms have been under investigation explaining such performance improvements. However, it has been shown in other exercise tasks that training-induced changes also occur at the level of the central nervous system. Therefore, we hypothesized to observe an enhanced neuromuscular performance in conjunction with an increase in endurance performance after 2 weeks of SIT. Therefore, we randomly assigned 19 healthy men (26 ± 5 years) to a control (n = 10) or a training group (n = 9), the latter performing a replication of the SIT protocol from Burgomaster et al. Before and after the training intervention, both groups performed a cycling endurance test until exhaustion. Neuromuscular function of the right vastus lateralis muscle was assessed before and after each endurance task by the means of maximal voluntary isometric contractions (MVCs). The variables of interest being MVC, voluntary activation was measured by peripheral nerve stimulations (VAPNS), by transcranial magnetic stimulation (VATMS), as well as potentiated resting twitches (Qtw,pot). We did not find any significant differences between the groups in the control variable time to exhaustion in the endurance task. In addition, we did not observe any time × group interaction effect in any of the neuromuscular parameters. However, we found a significant large-sized time effect in all neuromuscular variables (MVC, = 0.181; VATMS, = 0.250; VAPNS, = 0.250; Qtw,pot, = 0.304) as well as time to exhaustion = 0.601). In contrast to other studies, we could not show that a short-term SIT is able to increase endurance performance. An unchanged endurance performance after training most likely explains the lack of differences in neuromuscular variables between groups. These findings demonstrate that replication studies are needed to verify results no matter how strong they seem to be. Differences over time for the variables of neuromuscular fatigue irrespective of group (MVC, + 9.3%; VATMS, + 0.2%; VAPNS, + 6.3%; Qtw,pot, + 6.3%) demonstrate test-retest effects that should be taken into consideration in future training studies and emphasize the inevitable necessity for controlled experiments.

Caffeine Increased Muscle Endurance Performance Despite Reduced Cortical Activation and Unchanged Neuromuscular Efficiency and Corticomuscular Coherence.

The central and peripheral effects of caffeine remain debatable. We verified whether increases in endurance performance after caffeine ingestion occurred together with changes in primary motor cortex (MC) and prefrontal cortex (PFC) activation, neuromuscular efficiency (NME), and electroencephalography–electromyography coherence (EEG–EMG coherence). Twelve participants performed a time-to-task failure isometric contraction at 70% of the maximal voluntary contraction after ingesting 5 mg/kg of caffeine (CAF) or placebo (PLA), in a crossover and counterbalanced design. MC (Cz) and PFC (Fp1) EEG alpha wave and vastus lateralis (VL) muscle EMG were recorded throughout the exercise. EEG–EMG coherence was calculated through the magnitude squared coherence analysis in MC EEG gamma-wave (CI > 0.0058). Moreover, NME was obtained as the force–VL EMG ratio. When compared to PLA, CAF improved the time to task failure (p = 0.003, d = 0.75), but reduced activation in MC and PFC throughout the exercise (p = 0.027, d = 1.01 and p = 0.045, d = 0.95, respectively). Neither NME (p = 0.802, d = 0.34) nor EEG–EMG coherence (p = 0.628, d = 0.21) was different between CAF and PLA. The results suggest that CAF improved muscular performance through a modified central nervous system (CNS) response rather than through alterations in peripheral muscle or central–peripheral coupling.

Genes Whose Gain or Loss-of-Function Increases Endurance Performance in Mice: A Systematic Literature Review.

Endurance is not only a key factor in many sports but endurance-related variables are also associated with good health and low mortality. Twin and family studies suggest that several endurance-associated traits are ≈50% inherited. However, we still poorly understand what DNA sequence variants contribute to endurance heritability. To address this issue, we conducted a systematic review to identify genes whose experimental loss or gain-of-function increases endurance capacity in mice. We found 31 genes including two isoforms of Ppargc1a whose manipulation increases running or swimming endurance performance by up to 1800%. Genes whose gain-of-function increases endurance are Adcy5, Adcy8, Hk2, Il15, Mef2c, Nr4a3, Pck1 (Pepck), Ppard, Ppargc1a (both the a and b isoforms of the protein Pgc-1α), Ppargc1b, Ppp3ca (calcineurin), Scd1, Slc5a7, Tfe3, Tfeb, Trib3 & Trpv1. Genes whose loss-of-function increases endurance in mice are Actn3, Adrb2, Bdkrb2, Cd47, Crym, Hif1a, Myoz1, Pappa, Pknox1, Pten, Sirt4, Thbs1, Thra, and Tnfsf12. Of these genes, human DNA sequence variants of ACTN3, ADCY5, ADRB2, BDKRB2, HIF1A, PPARD, PPARGC1A, PPARGC1B, and PPP3CA are also associated with endurance capacity and/or VO2max trainability suggesting evolutionary conservation between mice and humans. Bioinformatical analyses show that there are numerous amino acid or copy number-changing DNA variants of endurance genes in humans, suggesting that genetic variation of endurance genes contributes to the variation of human endurance capacity, too. Moreover, several of these genes/proteins change their expression or phosphorylation in skeletal muscle or the heart after endurance exercise, suggesting a role in the adaptation to endurance exercise.

Effects of Small-Sided Games vs. Conventional Endurance Training on Endurance Performance in Male Youth Soccer Players: A Meta-Analytical Comparison

Small-sided games have been suggested as a viable alternative to conventional endurance training to enhance endurance performance in youth soccer players. This has important implications for long-term athlete development because it suggests that players can increase aerobic endurance through activities that closely resemble their sport of choice. The objectives of this meta-analysis were to compare male youth soccer players' adaptability to small-sided games vs. conventional endurance training and to establish exercise prescription guidelines for this population. The data sources utilised were Google Scholar, PubMed and Microsoft Academic. Studies were eligible for inclusion if interventions were carried out in male soccer players (aged < 18years) and compared the effects of small-sided games and conventional endurance training on aerobic endurance performance. We defined small-sided games as "modified [soccer] games played on reduced pitch areas, often using adapted rules and involving a smaller number of players than traditional games". We defined conventional endurance training as continuous running or extensive interval training consisting of work durations > 3min. The inverse-variance random-effects model for meta-analyses was used because it allocates a proportionate weight to trials based on the size of their individual standard errors and facilitates analysis whilst accounting for heterogeneity across studies. Effect sizes were represented by the standardised mean difference and presented alongside 95% confidence intervals. Seven studies were included in this meta-analysis. Both modes of training were effective in increasing endurance performance. Within-mode effect sizes were both of moderate magnitude [small-sided games: 0.82 (95% confidence interval 0.05, 1.60), Z = 2.07 (p = 0.04); conventional endurance training: 0.89 (95% confidence interval 0.06, 1.72), Z = 2.10 (p = 0.04)]. There were only trivial differences [0.04 (95% confidence interval -0.36, 0.43), Z = 0.18 (p = 0.86)] between the effects on aerobic endurance performance of small-sided games and conventional endurance training. Subgroup analyses showed mostly trivial differences between the training methods across key programming variables such as set duration (≥ or < 4min) and recovery period between sets (≥ or < 3min). Programmes that were longer than 8weeks favoured small-sided games [effect size = 0.45 (95% confidence interval -0.12, 1.02), Z = 1.54 (p = 0.12)], with the opposite being true for conventional endurance training [effect size = -0.33 (95% confidence interval -0.79, 0.14), Z = 1.39 (p = 0.16)]. Programmes with more than 4 sets per session favoured small-sided games [effect size = 0.53 (95% confidence interval -0.52, 1.58), Z = 0.98 (p = 0.33)] with only a trivial difference between those with 4, or fewer, sets [effect size =-0.13 (95% confidence interval -0.52, 0.26), Z = 0.65 (p = 0.52)]. Small-sided games are as effective as conventional endurance training for increasing aerobic endurance performance in male youth soccer players. This is important for practitioners as it means that small-sided games can allow both endurance and skills training to be carried out simultaneously, thus providing a more efficient training stimulus. Small-sided games offer the same benefits as conventional endurance training with two sessions per week, with ≥ 4 sets of 4min of activity, interspersed with recovery periods of 3min, recommended in this population.

High-Intensity Interval Training in Panic Disorder Patients: A Pilot Study.

High-intensity interval training (HIIT) may produce strong physiological but also psychological effects within a short period. However, it is questionable if this type of training is applicable and effective in patients with panic disorder (PD) because they are more vulnerable to the adverse effects of exercise. Twelve PD patients performed a 12-day HIIT trial. Every second day, patients performed 10 high-intensive 1-minute intervals at 77% to 95% of their maximum heart rate separated by 1-minute intervals with moderate to low intensity. All patients completed the 12-day training period. PD severity, agoraphobia, depression, general disorder severity, and endurance performance improved substantially with moderate to large effects sizes. Moreover, the increase in endurance performance was correlated with the reduction of depression and agoraphobia. HIIT was well tolerated by patients with PD and may induce rapid and strong therapeutic effects. A randomized controlled clinical trial is needed to verify our findings.

Increasing Iron Status through Dietary Supplementation in Iron-Depleted, Sedentary Women Increases Endurance Performance at Both Near-Maximal and Submaximal Exercise Intensities

Iron deficiency persists as the most common micronutrient deficiency globally, despite having known detrimental effects on physical performance. Although iron supplementation and aerobic exercise have been examined individually and are known to improve physical performance, the impact of simultaneous iron supplementation and aerobic training remains unclear. The aim of this study was to examine the individual and combined effects of iron supplementation and aerobic training on improving maximal and submaximal physical performance in iron-depleted, nonanemic (IDNA) women. We hypothesized that women receiving iron would improve their endurance performance but not their estimated maximal oxygen consumption (eVO2max). Seventy-three sedentary, previously untrained IDNA (serum ferritin <25 µg/L and hemoglobin >110 g/L) women aged 18-26 y with a body mass index (kg/m2) of 17-25 participated in a double-blind, 8-wk, randomized controlled trial with a 2×2 factorial design including iron supplementation (42 mg elemental Fe/d) or placebo and aerobic exercise training (5 d/wk for 25 min at 75-85% of age-predicted maximum heart rate) or no training. Linear models were used to examine relations between training, supplement, and changes in the primary outcomes of observed maximal oxygen consumption (VO2peak) and eVO2max and ventilatory threshold (absolute oxygen consumption and percentage of maximum). Re-evaluation of a published meta-analysis was used to compare effects of iron supplementation on maximal oxygen consumption (VO2max) and VO2peak. There were significant training-by-supplement interactions for VO2peak, volume of oxygen consumption at the ventilatory threshold, and the percentage of eVO2max where the threshold occurred, with the iron-untrained group performing better than the placebo-untrained group. There was no beneficial effect of iron supplementation for VO2max (mean difference: 0.53; 95% CI: -0.75, 1.81; P=0.42), but a significant benefit was observed for VO2peak (mean difference: 1.87; 95% CI: 0.15, 3.60; P=0.03). Iron supplementation increases endurance performance at submaximal and maximal (VO2peak) exercise intensities in IDNA women. However, increasing iron status does not increase eVO2max. This trial was registered at clinicaltrials.gov as NCT03002090.

Effects of Ketone Bodies on Endurance Exercise.

Priorities for every athlete include improving endurance performance, optimizing training, nutrition, and recovery. Nutritional strategies are crucial to support athletes to perform at the highest level, and considering that muscular and hepatic glycogen stores are limited, alternative strategies to maximize fat metabolism have been suggested. A ketogenic diet has been proposed as a possible method of providing metabolic fuel during prolonged periods of exercise. However, clinical trials and empirical experience have produced contrasting results regarding the ergogenic value of a ketogenic diet. For this reason, using ketone esters and/or salts have been proposed to obtain nutritional ketosis without limiting carbohydrate intake. Exogenous ketones should not only represent an alternative metabolic fuel source, sparing carbohydrates, but they also may increase postexercise glycogen replenishment, decrease proteolysis, and act as metabolic modulators and signaling metabolites. While there are some encouraging results showing an increase in endurance performance, contrasting evidence regarding the efficacy of exogenous ketones for endurance performance is present and further studies should be performed to make a definitive statement.

Lack of cyclin D3 induces skeletal muscle fiber-type shifting, increased endurance performance and hypermetabolism

The mitogen-induced D-type cyclins (D1, D2 and D3) are regulatory subunits of the cyclin-dependent kinases CDK4 and CDK6 that drive progression through the G1 phase of the cell cycle. In skeletal muscle, cyclin D3 plays a unique function in controlling the proliferation/differentiation balance of myogenic progenitor cells. Here, we show that cyclin D3 also performs a novel function, regulating muscle fiber type-specific gene expression. Mice lacking cyclin D3 display an increased number of myofibers with higher oxidative capacity in fast-twitch muscle groups, primarily composed of myofibers that utilize glycolytic metabolism. The remodeling of myofibers toward a slower, more oxidative phenotype is accompanied by enhanced running endurance and increased energy expenditure and fatty acid oxidation. In addition, gene expression profiling of cyclin D3−/− muscle reveals the upregulation of genes encoding proteins involved in the regulation of contractile function and metabolic markers specifically expressed in slow-twitch and fast-oxidative myofibers, many of which are targets of MEF2 and/or NFAT transcription factors. Furthermore, cyclin D3 can repress the calcineurin- or MEF2-dependent activation of a slow fiber-specific promoter in cultured muscle cells. These data suggest that cyclin D3 regulates muscle fiber type phenotype, and consequently whole body metabolism, by antagonizing the activity of MEF2 and/or NFAT.

Correction to: The Effect of Acute Caffeine Ingestion on Endurance Performance: A Systematic Review and Meta-Analysis.

Caffeine is a widely used ergogenic aid with most research suggesting it confers the greatest effects during endurance activities. Despite the growing body of literature around the use of caffeine as an ergogenic aid, there are few recent meta-analyses which quantitatively assess the effect of caffeine on endurance exercise. To summarise studies which have investigated the ergogenic effects of caffeine on endurance time-trial performance and to quantitatively analyse the results of these studies to gain a better understanding of the magnitude of caffeine's ergogenic effect on endurance time-trial performance. A systematic review was carried out on randomised placebo-controlled studies investigating the effects of caffeine on endurance performance and a meta-analysis was conducted to determine the ergogenic effect of caffeine on endurance time-trial performance. 44 studies met the inclusion criteria and were included in the meta-analysis. Caffeine has a small but evident effect on endurance performance when taken in moderate doses (3-6mg·kg-1) as well as an overall improvement following caffeine compared to placebo in mean power output (2.92 ± 2.18%; EffectSize = 0.22 ± 0.15) and time-trial completion time (2.26 ± 2.60%; Effect Size = 0.28 ± 0.12). However, differences in responses to caffeine ingestion have been shown, with two studies reporting slower time-trial performance while five studies reported lower mean power output during the time-trial. Caffeine can be used effectively as an ergogenic aid when taken in moderate doses, such as during sports when a small increase in endurance performance can lead to significant differences in placements as athletes are often separated by small margins.

The Effect of Acute Caffeine Ingestion on Endurance Performance: A Systematic Review and Meta-Analysis.

Caffeine is a widely used ergogenic aid with most research suggesting it confers the greatest effects during endurance activities. Despite the growing body of literature around the use of caffeine as an ergogenic aid, there are few recent meta-analyses that quantitatively assess the effect of caffeine on endurance exercise. To summarise studies that have investigated the ergogenic effects of caffeine on endurance time-trial performance and to quantitatively analyse the results of these studies to gain a better understanding of the magnitude of the ergogenic effect of caffeine on endurance time-trial performance. A systematic review was carried out on randomised placebo-controlled studies investigating the effects of caffeine on endurance performance and a meta-analysis was conducted to determine the ergogenic effect of caffeine on endurance time-trial performance. Forty-six studies met the inclusion criteria and were included in the meta-analysis. Caffeine has a small but evident effect on endurance performance when taken in moderate doses (3-6mg/kg) as well as an overall improvement following caffeine compared to placebo in mean power output (3.03 ± 3.07%; effect size = 0.23 ± 0.15) and time-trial completion time (2.22 ± 2.59%; effect size = 0.41 ± 0.2). However, differences in responses to caffeine ingestion have been shown, with two studies reporting slower time-trial performance, while five studies reported lower mean power output during the time-trial. Caffeine can be used effectively as an ergogenic aid when taken in moderate doses, such as during sports when a small increase in endurance performance can lead to significant differences in placements as athletes are often separated by small margins.

Apoptosis In Recovering Human Skeletal Muscle after High Intensity Cycling In Men Receiving Ergogenic Rg1 Compound

PURPOSE: To examine the impact of high intensity exercise on cell death in human skeletal muscle during recovery with Rg1 supplementation, which has been shown to increase endurance performance. METHODS: Using randomized double blind placebo controlled crossover design, twelve young men were studied on three occasions: Placebo, Rg1 (1 mg) and Rg1 (5 mg) supplementation 1 h prior to a high-intensity exercise. Biopsied samples were taken from vastus lateralis before, immediately after and 3 h after a 1-h cycling exercise at 75% VO2max. RESULTS: Apoptotic and necrotic cells in vastus lateralis increased immediately after 1 h cycling (80-140% and 80-120%, P < 0.05), concurrent with macrophage infiltration (both CD68+ and CD163+). Increases in iNOS and myogenic factor Myf5 mRNA levels after exercise were further elevated during Rg1 supplemented trial. Rg1 (5 mg) significantly increased high intensity endurance performance and accelerates the disappearance of apoptotic and necrotic cell number occurred 3 h after exercise during recovery. CONCLUSION: High intensity exercise increased cell death in human skeletal muscle after high intensity aerobic exercise. The ergogenic compound Rg1 accelerates phagocytosis to remove unhealthy muscle cell in exercised skeletal muscle.

Endurance performance is enhanced by intermittent hyperbaric exposure via up-regulation of proteins involved in mitochondrial biogenesis in mice.

This study was designed to (1) investigate the effects of acute hyperbaric exposure on muscle mRNA expression levels, and (2) clarify the mechanisms by which intermittent hyperbaric exposure improves endurance capacity. Experiment 1: Male mice were subjected to acute 1‐h hyperbaric exposure (1.3 atmospheres absolute with 20.9% O2). The expression of peroxisome proliferator‐activated receptor gamma coactivator 1‐alpha (PGC‐1α) mRNA significantly increased in the soleus (7.2‐fold) and red gastrocnemius muscles (Gr, 5.1‐fold) 3 h after hyperbaric exposure. Peroxisome proliferator‐activated receptor alpha (PPAR α) mRNA levels significantly increased in the plantaris (PL, 2.9‐fold) and Gr (2.3‐fold) 3 h after hyperbaric exposure. Experiment 2: Mice were subjected to exercise training with (HypTr) and without (Tr) 1‐h hyperbaric exposure for 4 weeks. Increases in maximal exercise capacity were significantly greater in HypTr than in Tr. In PL, activity levels of 3‐hydroxyacyl‐CoA‐dehydrogenase and citrate synthase (CS) were significantly greater in HypTr than in Tr. CS and phosphofructokinase activities both markedly increased in the white gastrocnemius muscle (Gw) in HypTr only. PGC‐1α expression in the nucleus was significantly greater in HypTr than in Tr in PL (4.8‐fold), Gr (3.2‐fold), and Gw (15‐fold). Protein levels of mitochondrial transcription factor A and heat shock protein 70 significantly increased after training with hyperbaric exposure. These results suggest that exercise training with intermittent hyperbaric exposure represents a beneficial strategy for increasing endurance performance by facilitating oxidative and glycolytic capacities and the expression of proteins involved in mitochondrial biogenesis in the hindlimb muscles.

No Adverse Effects of Matcha Green Tea Powder on Metabolic and Physiological Responses during Running

Matcha is powder made from green tea leaves that had restricted light exposure to enhance composition. Consumption of the powder in Matcha green tea drinks ensures substantially higher intake of catechins and caffeine than normally brewed green tea. Green tea effects are commonly examined with epigallocatechin gallate (EGCG) or green tea extract with evidence to support enhanced fat oxidation and increased endurance performance. The metabolic and physiologic responses of short-duration intake of Matcha green tea powder during exercise are not known. PURPOSE: To examine the metabolic and physiological responses of Matcha green tea powder during submaximal treadmill running. METHODS: Twelve male recreational runners (mean±SD, age: 31±9 years, height: 185±9 cm, body mass: 79±11 kg, maximum oxygen uptake (V[Combining Dot Above]O2max): 55±6 mL[BULLET OPERATOR]kg-1[BULLET OPERATOR]min-1) completed a 40-minute treadmill run at 55% of the running speed at V[Combining Dot Above]O2max, i.e. running at 10.0±0.8 km[BULLET OPERATOR]h-1. In the Matcha condition, participants were supplemented with 3x3 capsules on the day before and 3 capsules one hour before exercise in a fasted state. Each capsule contains 77 mg total catechins of which 37.5 mg EGCG and 12 mg caffeine. Expired air, heart rate and rating of perceived exertion (RPE) were collected at 10-minute intervals and analysed with two-way repeated measures and Bonferroni post hoc testing. Significance was accepted at p<0.05. RESULTS: There was no condition effect of Matcha green tea powder at any time point on minute ventilation, oxygen consumption, fat oxidation, carbohydrate oxidation, heart rate and RPE. For example, fat oxidation values and heart rates during 9-10 min, 19-20 min, 29-30 min and 39-40 min were 0.63±18, 0.65±0.24, 0.71±0.17, 0.80±0.24 g·min-1 and 0.63±0.22, 0.67±0.26, 0.67±0.22, 0.73±0.24 g·min-1, and 139±13, 145±14, 148±14, 150±14 beats·min-1 and 140±13, 144±13, 147±13, 150±13 beats·min-1, for the control and Matcha condition, respectively. CONCLUSION: Short-duration intake of Matcha green tea powder had no adverse effects on metabolic and physiological responses during submaximal intensity running. Future studies should address whether there is an effect of long-duration intake of Matcha green tea on metabolic and physiological responses and exercise performance. Matcha capsules were provided by OMGTEA Ltd, United Kingdom.

Analyses of Meldonium (Mildronate) from Blood, Dried Blood Spots (DBS), and Urine Suggest Drug Incorporation into Erythrocytes.

Initially developed in the late 1970s for veterinary applications due to proposed growth-promoting effects in animals [5], meldonium has become an approved drug in selected Eastern European countries and is the subject of ongoing clinical trials focusing the compound’s anti-ischemic and cardioprotective properties [2] [3] [12] [15] as well as potential applications regarding diabetes, neurodegenerative disorders, and bronchopulmonary diseases. In the context of athletic performance, beneficial effects on the individuals’ physical working capacity, increased endurance performance, and accelerated recovery after physical activity were discussed [4] [10] [11], mentioning oral doses of meldonium of up to 2.0 g per day over 2–3 weeks in the course of pre-competition preparation phases [4]. In 2015, the World Anti-Doping Agency (WADA) initiated a one-year monitoring program [22] regarding the prevalence of meldonium (mildronate) in doping controls. Obtained data demonstrated a considerable extent of meldonium use by athletes [8] [16], which was further corroborated by a significant number of declarations of use and analytical findings at the Baku 2015 European Games [18]. Subsequently, the WADA Prohibited List that became effective in January 2016 [24] classified meldonium as banned under S4 (Hormone and Metabolic Modulators).

Short-duration intermittent hypoxia enhances endurance capacity by improving muscle fatty acid metabolism in mice.

This study was designed to (1) investigate the effects of acute short‐duration intermittent hypoxia on muscle mRNA and microRNA expression levels; and (2) clarify the mechanisms by which short‐duration intermittent hypoxia improves endurance capacity. Experiment‐1: Male mice were subjected to either acute 1‐h hypoxia (12% O2), acute short‐duration intermittent hypoxia (12% O2 for 15 min, room air for 10 min, 4 times, Int‐Hypo), or acute endurance exercise (Ex). The expression of vascular endothelial growth factor‐A mRNA was significantly greater than the control at 0 h post Ex and 6 h post Int‐Hypo in the deep red region of the gastrocnemius muscle. miR‐16 expression levels were significantly lower at 6 and 10 h post Int‐Hypo. Peroxisome proliferator‐activated receptor gamma coactivator 1‐alpha (PGC‐1α) mRNA levels were significantly greater than the control at 3 h post Ex and 6 h post Int‐Hypo. miR‐23a expression levels were lower than the control at 6–24 h post Int‐Hypo. Experiment‐2: Mice were subjected to normoxic exercise training with or without intermittent hypoxia for 3 weeks. Increases in maximal exercise capacity were significantly greater by training with short‐duration intermittent hypoxia (IntTr) than without hypoxia. Both 3‐Hydroxyacyl‐CoA‐dehydrogenase and total carnitine palmitoyl transferase activities were significantly enhanced in IntTr. Peroxisome proliferator‐activated receptor delta and PGC‐1α mRNA levels were both significantly greater in IntTr than in the sedentary controls. These results suggest that exercise training under normoxic conditions with exposure to short‐duration intermittent hypoxia represents a beneficial strategy for increasing endurance performance by enhancing fatty acid metabolism in skeletal muscle.