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Ischemic preconditioning (IPC) can enhance maximal strength likely due to neural priming. Cruz et al. (Cruz R, Tramontin AF, Oliveira AS, Caputo F, Denadai BS, Greco CC. Scand J Med Sci Sports 34: e14591, 2024) examined the neurophysiological mechanisms responsible for the ergogenic effect. Although key neurophysiological measures remained largely unchanged, voluntary activation and maximal strength were greater following IPC than sham-IPC. Although the mechanistic evidence remains inconclusive, the greater maximal strength provides further evidence of the ergogenic benefit of IPC. Researchers should continue examining the broader functional implications of IPC. [ABSTRACT FROM AUTHOR]

The ergogenecity of caffeine (CAF) and pre-exercise music have been studied extensively in male and mixed-gender groups, but there is limited information on their synergistic effects in females. This study assessed the effects of combining a low dose of CAF with warm-up music on taekwondo specific performance, perceived exertion (RPE), and psychological aspects in female athletes. In a double-blinded, randomized, placebo-controlled crossover study, 16 female taekwondo athletes (M ± SD; age: 17.69 ± 0.60 years) performed the taekwondo-specific agility test (TSAT), 10 s frequency speed of kick test (FSKT-10s) and its multiple version (FSKT-mult) under the following conditions: 1) no supplement with music (NS+M); 2) no supplement without music (control); 3) CAF without music (CAF+NM), 4) placebo without music (PL+NM), 5) CAF with music (CAF+M), 6) PL with music (PL+M). After each test, athletes rated their RPE, feeling scale (FS), felt arousal scale (FAS) and physical enjoyment (PACES). CAF+M induced better physical performance than other conditions on the FSKT-10s, FSKT-mult, and more desirable psychophysiological responses including RPE post_TSAT, RPE post_FSKT-10s, PACES post_FSKT-10s, FS, FAS post_warm-up, FAS post_FSKT-10s and FAS post_FSKTmult (all p < 0.05). Except for PL+M, CAF+M also elicited more desirable responses than other conditions for FAS post_TSAT (p < 0.05). Furthermore, CAF+M and CAF+NM conditions enhanced TSAT, PACES post_TSAT, RPE post_FSKTmult greater than the other conditions (p < 0.05). Preceding warm-up music stimulus with a low dose of CAF may be a more efficient strategy to enhance physical performance and affective valence in female taekwondo athletes compared with using either strategy in isolation. [ABSTRACT FROM AUTHOR]

The ergogenecity of caffeine (CAF) and pre-exercise music have been studied extensively in male and mixed-gender groups, but there is limited information on their synergistic effects in females. This study assessed the effects of combining a low dose of CAF with warm-up music on taekwondo specific performance, perceived exertion (RPE), and psychological aspects in female athletes. In a double-blinded, randomized, placebo-controlled crossover study, 16 female taekwondo athletes (M ± SD; age: 17.69 ± 0.60 years) performed the taekwondo-specific agility test (TSAT), 10 s frequency speed of kick test (FSKT-10s) and its multiple version (FSKT-mult) under the following conditions: 1) no supplement with music (NS+M); 2) no supplement without music (control); 3) CAF without music (CAF+NM), 4) placebo without music (PL+NM), 5) CAF with music (CAF+M), 6) PL with music (PL+M). After each test, athletes rated their RPE, feeling scale (FS), felt arousal scale (FAS) and physical enjoyment (PACES). CAF+M induced better physical performance than other conditions on the FSKT-10s, FSKT-mult, and more desirable psychophysiological responses including RPE post_TSAT, RPE post_FSKT-10s, PACES post_FSKT-10s, FS, FAS post_warm-up, FAS post_FSKT-10s and FAS post_FSKT-mult (all p < 0.05). Except for PL+M, CAF+M also elicited more desirable responses than other conditions for FAS post_TSAT (p < 0.05). Furthermore, CAF+M and CAF+NM conditions enhanced TSAT, PACES post_TSAT, RPE post_FSKT-mult greater than the other conditions (p < 0.05). Preceding warm-up music stimulus with a low dose of CAF may be a more efficient strategy to enhance physical performance and affective valence in female taekwondo athletes compared with using either strategy in isolation.

Purpose: To compare the acute effects of caffeine and placebo ingestion with a control condition (ie, no supplementation) on vertical jump performance. Methods: The sample for this study consisted of 26 recreationally trained men. Following the familiarization visit, the subjects were randomized in a double-blind manner to 3 main conditions: placebo, caffeine, and control. Caffeine was administered in the form of a gelatin capsule in the dose of 6 mg·kg body weight-1. Placebo was also administered in the form of a gelatin capsule containing 6 mg·kg-1 of dextrose. Vertical jump performance was assessed using a countermovement jump performed on a force platform. Analyzed outcomes were vertical jump height and maximal power output. Results: For vertical jump height, significant differences were observed between placebo and control conditions (g = 0.13; 95% confidence interval [CI], 0.03-0.24; +2.5%), caffeine and control conditions (g = 0.31; 95% CI, 0.17-0.50; +6.6%), and caffeine and placebo conditions (g = 0.19; 95% CI, 0.06-0.34; +4.0%). For maximal power output, no significant main effect of condition (P = .638) was found. Conclusions: Ingesting a placebo or caffeine may enhance countermovement jump performance compared with the control condition, with the effects of caffeine versus control appearing to be greater than the effects of placebo versus control. In addition, caffeine was ergogenic for countermovement jump height compared with placebo. Even though caffeine and placebo ingestion improved vertical jump height, no significant effects of condition were found on maximal power output generated during takeoff. [ABSTRACT FROM AUTHOR]

To determine the acute effect of low and high-dose BA trials on maximal aerobic speed (MAS) in endurance athletes. We hypothesized that high doses of BA have a greater effect than low doses, both compared to baseline. Twelve male endurance athletes volunteered for the study (age = 21.8 ± 2.37 years, weight = 69.8 ± 4.36 kg, height = 174 ± 5.45 cm, maximal oxygen uptake = 59.6 ± 3.77 mLO2·kg−1·min−1). The experimental design applied was randomized cross-over, double-blind. Treatment included three 6-minute run tests (6-MRT), the first as a baseline, then randomized 6-MRT with low (30 mg·kg−1) and high (45 mg·kg−1) dose BA trials. The 6-MRTs were separated by 72 hours. The main variable of the study was the distance (m) performed in the 6-MRT. Differences between tests were established through ANOVA and Tukey's multiple comparison tests (p < 0.05). The analysis showed significant differences between baseline and both doses (p < 0.001). No significant differences were observed between low and high-dose BA trials (p > 0.05). Both 30 and 45 mg·kg−1 of BA increased physical performance at maximal aerobic speed in endurance athletes. The acute intake formats described in the present investigation may be helpful for endurance athletes training and competing in aerobic-anaerobic transition zones. [ABSTRACT FROM AUTHOR]

Endurance, which is dependent at least partly upon the activation of the brain cortex, is important for performance in rowing. Transcranial direct current stimulation (tDCS) has shown benefits for endurance, but its effects on the endurance performance of elite rowing athletes are unknown, and are examined in this study. Eight elite female rowers completed 5 km of rowing on an ergometer following stimulation of the tDCS and sham over motor cortices. Each session lasted 20 min and the current was set at 2.2 mA. Time, 500 m/split, power, time corresponding to 500 m (TC500) and power corresponding to 500 m (PC500) were recorded continuously throughout the tests. No significant differences in time, 500 m/split and power were observed between baseline, tDCS and sham. Compared to the sham, tDCS induced a percentage reduction in TC500 from baseline to 2500 m and 4000 m, and a percentage increase in PC500 from baseline to 500 m, 1000 m, 1500 m, 2000 m, 2500 m, 4000 m, 4500 m and 5000 m. One-session tDCS did not have significant benefits for rowing endurance performance in elite professional rowers, and had only marginally greater efficacy compared to sham. These findings offer knowledge helpful to the design of future studies exploring the effects of tDCS on the endurance performance of elite rowers. [ABSTRACT FROM AUTHOR]

The ergogenic effects of carbohydrate (CHO) and caffeine (CAF) mouth rinse (MR) methods on anaerobic performance remains unclear. Therefore, the aim of this study was to investigate the effects of CHO, CAF, and CHO + CAF combination solutions in mouth on repeated vertical jumping (RVJ) performance in highly trained male athletes. Eight male athletes (mean age: 22 years) underwent test sessions four times with minimum 24-h intervals under fasting conditions. Participants rinsed their mouths with four different 25-ml solutions, namely, CHO (6.4% maltodextrin = 1.6 g), CAF (1.2% caffeine = 300 mg), placebo (PLA, saccharin), or CHO + CAF (6.4%+1.2%) combination, for 10 s and performed a 30-s RVJ test twice with a 5-min interval. Peak power output, vertical jump height, blood lactate level, fatigue index, and rate of perceived exertion of the RVJ tests for different intervention sessions were compared. The statistical significance level was set at p ≤ 0.05. Analyses demonstrated that CHO- (Δ: 3.4), CAF- (Δ: −0.8), and CHO + CAF-MR (Δ: −1.8) interventions led to similar RVJ performance changes compared to PLA. All differences in the dependent variables were statistically insignificant and had moderate and lower effect sizes between interventions (p > 0.05, g < 0.94). Our study did not elicit sufficient evidence to recommend highly trained male athletes the use of CHO- and CAF-MR separately or in combination to enhance jump performance. However, the fact that some differences have medium to large effect sizes suggests that the issue is still worth to be a potential topic for further research. Highlights Effects of CHO + CAF-MR on anaerobic performance in highly trained athletes have not been investigated using performance tasks requiring high technical skills. There is not enough evidence to suggest that CHO, CAF and CHO + CAF-MR interventions have beneficial effects on RVJ performance compared to PLA in highly trained male athletes. Some statistically insignificant differences have medium to large effect sizes. Therefore, the issue is still worth to be a potential topic for further research. [ABSTRACT FROM AUTHOR]

This study aimed to examine the effect of dextrose drink (D) on blood glucose, VO 2 max, and sprint speed compared with Sodium-Dextrose drink. Equipment and Methods : We conducted a double-blinded crossover study of 22 young male (19 ± 1.1 years) soccer players, consumed either Dextrose drink or Sodium-Dextrose drink. We compared pre- and post-data of Blood Glucose, VO 2 max, and sprint speed between the dextrose and sodium-dextrose drinks groups. The primary outcome was differences in ΔBlood Glucose between D and Sodium-D group. Secondary outcomes were differences in ΔVO 2 max and Δsprint speed between D and Sodium-D group. The mean BG level was higher in D compared with Sodium-D group [136 ± 22.9 mg/dl vs. 118 ± 21.5 mg/dl] (P = 0.009). Mean differences of ΔBG of D (mean before and mean after) compared with ΔBG Sodium-D (mean before and mean after) is 16.8 mg/dl (P = 0.001). The mean of sprint speed is faster in the D group [15.2 ± 1.25 sec vs. 15.9 ± 1.61 sec] (P = 0.019), but we found no significant differences in VO 2 max between both groups [42.1 ± 3.44 ml/min/kg vs. 42.3 ± 3.98 ml/min/kg] (P = 0.834). The present study demonstrated that dextrose drink without added sodium has a large influence on increasing blood glucose level and sprint speed. [ABSTRACT FROM AUTHOR]

Background: Stimulant medications used for the treatment of Attention Deficit-Hyperactivity Disorder (ADHD) are believed to provide a physical advantage in athletics, but several of these medications are not regulated by the World Anti-Doping Association. Given the prevalence of ADHD among the athlete population and concern for abuse of ADHD medications, this review and meta-analysis aimed to evaluate effects of ADHD medications on athletic performance, thereby appraising the validity of claims of performance enhancement. Methods: A search of MEDLINE, Embase, CINAHL, and Cochrane Review databases was performed for all randomized controlled trials evaluating athletic performance after ingestion of placebo or ADHD treatment medications from August 2020 through November 2020. All RCTs identified from these search criteria were included for screening, with exclusion of any animal studies. Two reviewers (JB, CK) assessed methodological quality and risk of bias using CONSORT 2010 and Cochrane Collaboration tools. Study results were compiled with corresponding p values for each finding. Effect sizes (Cohen's D) for athletic performance and physiological changes were aggregated for each study. Studies were further screened for homogeneity that would allow for meta-analysis. Heterogeneity was calculated using I2. Results: A total of 13,033 abstracts evaluating amphetamine, methamphetamine, methylphenidate, and bupropion were screened. The final analysis included nine studies, six of which found significant improvement in athletic performance with use of stimulant medications (p < 0.05). Methylphenidate and amphetamine were consistently identified to have a performance effect. Secondary effects identified included significant increase in heart rate, core temperature, and elevation of various serum hormone levels (p < 0.05). Effect size evaluation found seven studies demonstrating small to large effects on physical performance, as well as in categories of cardiometabolic, temperature, hormone, and ratings of perceived exertion, to varying degrees. A meta-analysis was performed on two studies, demonstrating conflicting results. Conclusions: Dopaminergic/noradrenergic agonist medications appear to have a positive effect on athletic performance, as well as effects on physiological parameters. Further consideration of medications currently not regulated, i.e. bupropion, is warranted given evidence of athletic performance enhancement. PROSPERO trial registration number: CRD42020211062; 10/29/2020 retrospectively registered. [ABSTRACT FROM AUTHOR]

Research studies address the benefits of music as a means for increasing arousal and work output. Research also indicates the positive contribution of music before or during an activity. In this study, we examined the use of music in physical education classes as a contributor to learner performance. The study included 109 6th-grade children (63 girls and 46 boys) who were asked to perform a medium distance running test (about 370 meters) in three situations: without music, while listening to slow music, and while listening to rhythmic music. The test was performed outdoors, and the children heard the music over the loudspeaker, for everyone to hear. Our findings indicate differences in the running times achieved by boys, whereby their results were better when listening to slow music than when performing without music. This finding raises the hypothesis that children respond differently to music compared to findings that are reported in the literature on adults, whereby girls may be less responsive to external stimulus, while boys may be able to channel slow music in such a way as to replace feelings of fatigue with greater energy . [ABSTRACT FROM AUTHOR]

Background: Acute caffeine ingestion has been associated with improvements in cognitive performance and visual functioning. The main objective of this study was to determine the effects of caffeine intake on dynamic visual acuity (DVA). Methods: Twenty-one low caffeine consumers (22.5 ± 1.6 years) took part in this placebo-controlled, double-blind, and balanced crossover study. In two different days and following a random order, participants ingested either caffeine (4 mg/kg) or placebo, and DVA was measured after 60 min of ingesting the corresponding capsule. A recently developed and validated software (moV& test, V&mp Vision Suite, Waterloo, Canada) was used to assess DVA. Results: We found a greater accuracy for both the horizontal and random motion paths of DVA after caffeine ingestion (p < 0.001 and p = 0.002, respectively). In regard to the speed of the response, our data revealed that caffeine intake was associated with a faster reaction time for horizontally (p = 0.012) but not for randomly (p = 0.846) moving targets. Also, participants reported higher levels of perceived activation after consuming caffeine in comparison to placebo (p < 0.001). Conclusions: Our data suggest that caffeine intake (i.e., a capsule containing 4 mg/kg) has an ergogenic effect on DVA, which may be of special relevance in real-word contexts that require to accurately and rapidly detect moving targets (e.g., sports, driving, or piloting). [ABSTRACT FROM AUTHOR]

The aim of this study was to investigate whether caffeine and/or sodium citrate have an ergogenic effect on the 1,500-m exercise performance in elite wheelchair athletes. A placebo-controlled, randomized, cross-over and double-blind study design was conducted with the four treatments placebo, caffeine, sodium citrate and the combination of caffeine and sodium citrate. Nine healthy, elite wheelchair-racing athletes (median: [min; max] age: 28 y [23; 54]; height: 173 cm [165; 188]; weight: 62.9 kg [48.9; 68.4], category T53/54) completed the study. All athletes were national team members, including several Paralympic Games, World and European Championship medalists. The athletes performed a 1,500-m time trial four times on a wheelchair training roller. Time to complete 1,500-m, pH, bicarbonate and sodium concentration as well as lactate concentration were measured. The time to complete 1,500-m was not significantly different between the four treatments (placebo: 170.6 s [141.7; 232.0]; caffeine: 179.5 s [134.8; 239.6]; sodium citrate: 178.3 s [136.4; 247.1]; combination: 177.6 s [136.1; 256.2]). However, pH and bicarbonate concentrations were significantly increased with sodium citrate ingestion compared with placebo. Moreover, maximal lactate concentrations were significantly higher in the caffeine and the combination treatment compared with placebo. The supplementation with sodium citrate and/or caffeine did not provide an ergogenic effect on the 1,500-m exercise performance in wheelchair elite athletes. [ABSTRACT FROM AUTHOR]

Endurance, which is dependent at least partly upon the activation of the brain cortex, is important for performance in rowing. Transcranial direct current stimulation (tDCS) has shown benefits for endurance, but its effects on the endurance performance of elite rowing athletes are unknown, and are examined in this study. Eight elite female rowers completed 5 km of rowing on an ergometer following stimulation of the tDCS and sham over motor cortices. Each session lasted 20 min and the current was set at 2.2 mA. Time, 500 m/split, power, time corresponding to 500 m (TC500) and power corresponding to 500 m (PC500) were recorded continuously throughout the tests. No significant differences in time, 500 m/split and power were observed between baseline, tDCS and sham. Compared to the sham, tDCS induced a percentage reduction in TC500 from baseline to 2500 m and 4000 m, and a percentage increase in PC500 from baseline to 500 m, 1000 m, 1500 m, 2000 m, 2500 m, 4000 m, 4500 m and 5000 m. One-session tDCS did not have significant benefits for rowing endurance performance in elite professional rowers, and had only marginally greater efficacy compared to sham. These findings offer knowledge helpful to the design of future studies exploring the effects of tDCS on the endurance performance of elite rowers.

Objective: The aim of this study was to identify the best energy dose of photobiomodulation therapy (PBMT) able to improve muscle performance and reduce fatigue during multiple-set knee extension exercise. Methods: Eighteen physically active men participated in this study. Each participant performed an isokinetic exercise protocol (5 sets of 10 knee extension repetitions, maximum contractions at 60°•s-1) in 6 sessions, 1 week apart. Control condition (no PBMT/placebo treatments) was applied at the first and sixth sessions. Placebo or PBMT with 135, 270, or 540 J/quadriceps was randomly applied from the second to fifth sessions. Placebo/PBMT treatments were always applied at two moments: 6 h before and immediately before exercise. The isometric and isokinetic concentric peak torques were assessed before and after the exercise protocol. Results: The knee extension exercise performance (total work performed during exercise) was not affected by PBMT (135, 270, and 540 J) compared with placebo treatment. However, all PBMT treatments (135, 270, and 540 J) led to lower percentage drop compared with placebo and control conditions on isometric peak torque (IPT), concentric peak torque (CPT), and concentric work (W). All PBMT doses led to possibly positive or likely positive effects on IPT, CPT, and W compared with placebo. Conclusions: Our findings demonstrate that PBMT with 135, 270, and 540 J applied at two moments (6 h before and immediately before exercise) was able to produce the same total work with lower fatigue, which may facilitate the performance of additional sets (i.e., higher training volume). [ABSTRACT FROM AUTHOR]

Background Fish oils were studied as ergogenic aids in a number of mixed physical trial designs showing promising results. However, the heterogeneous purity of the studied supplements, combined with the variety of physical tests employed call for more studies to confirm these findings, ideally with standardised supplements. Our aim was to test a supplement highly concentrated in DHA (DHA:EPA ratio equal to approximately 8:1) on a maximal cycling test to elucidate performance improvements mainly due to DHA. Methods A double-blind, placebo controlled, randomised balanced, parallel design, in competitive amateur cyclists was employed. They were all male, older than 18 years old, with training routine of 2 to 4 sessions per week lasting at least one hour each. A ramp cycling test to exhaustion with a subsequent 5 min recovery phase was employed before and after treatment to analyse aerobic metabolism and lactate clearance after the bout. After 30 days of supplementation with 975 mg of re-esterified DHA, the thirty-eight cyclist who completed the study were finally included for statistical analysis. Results Mean power output at ventilatory threshold 2 (VT2) improved after DHA supplementation both as absolute (△DHA versus △PLA: 6.33–26.54 Watts; CI 95%) and relative (p=0.006) values, paralleled with higher oxygen consumption at VT2 both for absolute (DHA 2729.4 ±304.5, 3045.9 ±335.0; PLA 2792.3 ±339.5, 2845.5 ±357.1; ml·min −1 baseline versus post p=0.025) and relative values (DHA 36.6 ±5.0, 41.2 ±5.4; PLA 37.2 ±5.7, 38.1 ±5.2; ml·kg −1·min −1 baseline versus post p=0.024). Heart rate recovery rate improved during the recovery phase in the DHA group compared to PLA (p=0.005). Conclusion DHA is capable of improving mean power output at the ventilatory threshold 2 (anaerobic ventilatory threshold) in amateur competitive cyclists. It is unclear if these findings are the result of the specific DHA supplement blend or another factor.

Copyright of Medicina Pro Praxi is the property of SOLEN sro and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

• Each odor has its mechanisms and its advantages in order to increase a physiological aspect during physical activity. • The pleasantness of odors seems important in order to maximize the positive effect during physical activity. • A consistent olfactory protocol to administer odors should be used to have better results among participants. Fewer and fewer people are reaching physical activity recommendations. Therefore, it seems important to make the practice of physical activity more enjoyable to increase the participation rate. Several environmental factors have been studied to see their impact on sports practice, and some studies investigated the effect of odors. This systematic review aims to provide a thorough view of the literature on the effect of different odors on physical activity. The search strategy consisted of using index terms and keywords in MEDLINE, EMBASE, EBM Reviews – Cochrane Central Register of Controlled Trials, CINAHL, SPORTDiscus, and Web of Science search engine. Data from 19 studies that included 458 participants revealed that the odors had different results on strength, cardiovascular, precision, and postural balance tasks depending on the odors' exposition. Among results, an important distinction was made between pleasant and unpleasant odors. Therefore, pleasant odors had better results on physical activity by improving participants' feeling. Even though this review clarified evidence about the effect of odors on physical activity, better methodological consistency is needed across studies such as the odor administration method to produce more meaningful results. [ABSTRACT FROM AUTHOR]

Introduction: The use of oral appliances to enhance sports performance has been advocated by some authors, however, studies addressing the effectiveness of these strategies are inconclusive. Methods: Here we investigate the effects of dental occlusions on shoulder strength. Fourteen healthy male subjects (age = 21.67 ± 0.86 years) without temporomandibular joint (TMJ) disorder participated in this study. Isokinetic strength was evaluated in shoulder abduction/adduction and arm external/internal rotation tests. Three randomised conditions were assessed: (1) occlusal splint (OS), which repositioned the TMJ in centric relation; (2) placebo splint (PS); and (3) no-splint (N). The strength tests were performed at a speed of 60°/sec in concentric mode. Muscle activity was measured by surface electromyography (EMG) in the main muscles engaged in the movements. Results: Significant differences in peak torque between OS and both of the other experimental conditions were found in some of the analyzed variables. Moreover, there was significantly higher muscular EMG activation in the OS condition when compared to the other conditions for some of the tested muscles. These data suggest that splints may have a positive ergogenic effect on shoulder muscular strength in healthy male subjects. Conclusion: OS may provide an advantage for healthy subjects engaged in sports whereby shoulder and arm strength are important for performance. Occlusal splints in centric relation position have an ergogenic effect, by increasing strength and muscle activation on shoulder in healthy subjects. These results could have implications for sports or other physical activities were arm and shoulder strength are important. [ABSTRACT FROM AUTHOR]

Strenuous exercise (any activity that expends six metabolic equivalents per minute or more causing sensations of fatigue and exhaustion to occur, inducing deleterious effects, affecting negatively different cells), induces muscle damage and hematological changes associated with high production of pro-inflammatory mediators related to muscle damage and sports anemia. The objective of this study was to determine whether short-term oral ubiquinol supplementation can prevent accumulation of inflammatory mediators and hematological impairment associated to strenuous exercise. For this purpose, 100 healthy and well-trained firemen were classified in two groups: Ubiquinol (experimental group), and placebo group (control). The protocol was two identical strenuous exercise tests with rest period between tests of 24 h. Blood samples were collected before supplementation (basal value) (T1), after supplementation (T2), after first physical exercise test (T3), after 24 h of rest (T4), and after second physical exercise test (T5). Hematological parameters, pro- and anti-inflammatory cytokines and growth factors were measured. Red blood cells (RBC), hematocrit, hemoglobin, VEGF, NO, EGF, IL-1ra, and IL-10 increased in the ubiquinol group while IL-1, IL-8, and MCP-1 decreased. Ubiquinol supplementation during high intensity exercise could modulate inflammatory signaling, expression of pro-inflammatory, and increasing some anti-inflammatory cytokines. During exercise, RBC, hemoglobin, hematocrit, VEGF, and EGF increased in ubiquinol group, revealing a possible pro-angiogenic effect, improving oxygen supply and exerting a possible protective effect on other physiological alterations.

Copyright of SPORMETRE: The Journal of Physical Education & Sport Sciences / Beden Eğitimi ve Spor Bilimleri Dergisi is the property of SPORMETRE: The Journal of Physical Education & Sport Sciences and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Background:Khat (Catha edulisForsk) is a natural psychoactive substance which contains two main addictive substances; Cathine and Cathinone. Khat is widely used in east Africa and southern Arabian Peninsula. Khat chewers believe that it improves work capacity and increases energy level and alertness. That is why we aimed in this study to investigate the physiological and ergogenic effects of khat extract.Methods:This study is an experimental study conducted at the Substance Abuse Research Centre in Jazan University, Saudi Arabia. Thirty healthy young volunteers were randomly assigned into two experimental groups. The first group ingested 45 g of grounded khat leaves extract mixed with juice in the first session then placebo (juice only) in the second session. While the second group ingested the placebo in the first session and the grounded khat leaves with juice in the second session. Experiments were done between December 2012 and March 2013. We recorded the blood pressure, heart rate, grip strength, and reaction time every 15 min for 75 min after each ingestion. The study proposal was reviewed and approved by Research Ethics Committee (REC) of the Medical Research Centre in Jazan University. Results: The results showed the consumption of 45 g of grounded khat leaves contributed to the increase in blood pressure (SBP & DBP) and reaction time (p< 0.05); but had no significant effect on heart rate and grip strength (p> 0.05).Conclusions:The findings of this study showed that Khat has an acute effect on some physiological parameters. These findings support the prohibition of cathinone and cathine by the World Anti-Doping Agency (WADA, 2016). [ABSTRACT FROM PUBLISHER]

Exercise has beneficial effects on our health by stimulating metabolic activation of skeletal muscle contraction. Caffeine is a powerful metabolic stimulant in the skeletal muscle that has ergogenic effects, including enhanced muscle power output and endurance capacity. In the present study, we aim to characterize the metabolic signatures of contracting muscles with or without caffeine stimulation using liquid chromatography-mass spectrometry and capillary electrophoresis coupled to mass spectrometry. Isolated rat epitrochlearis muscle was incubated in the presence or absence or of 3 mM caffeine for 30 min. Electrical stimulation (ES) was used to induce tetanic contractions during the final 10 min of incubation. Principal component analysis and hierarchical clustering analysis detected 184 distinct metabolites across three experimental groups—basal, ES, and ES with caffeine (ES + C). Significance Analysis of Microarray identified a total of 50 metabolites with significant changes in expression, and 23 metabolites significantly changed between the ES and ES + C groups. Changes were observed in metabolite levels of various metabolic pathways, including the pentose phosphate, nucleotide synthesis, β-oxidation, tricarboxylic acid cycle, and amino acid metabolism. In particular, D-ribose 5-phosphate, IMP, O-acetylcarnitine, butyrylcarnitine, L-leucine, L-valine, and L-aspartate levels were higher in the ES + C group than in the ES group. These metabolic alterations induced by caffeine suggest that caffeine accelerates contraction-induced metabolic activations, thereby contributing to muscle endurance performance and exercise benefits to our health.

We examined the effects of an adenosine receptor agonist on caffeine-induced changes in thermoregulation, neurotransmitter release in the preoptic area and anterior hypothalamus, and endurance exercise performance in rats. One hour before the start of exercise, rats were intraperitoneally injected with either saline alone (SAL), 10 mg kg − 1 caffeine and saline (CAF), a non-selective adenosine receptor agonist (5ʹ-N-ethylcarboxamidoadenosine [NECA]: 0.5 mg kg − 1 ) and saline (NECA), or the combination of caffeine and NECA (CAF + NECA). Rats ran until fatigue on the treadmill with a 5% grade at a speed of 18 m min − 1 at 23 °C. Compared to the SAL group, the run time to fatigue (RTTF) was significantly increased by 52% following caffeine administration and significantly decreased by 65% following NECA injection (SAL: 91 ± 14.1 min; CAF: 137 ± 25.8 min; NECA: 31 ± 13.7 min; CAF + NECA: 85 ± 11.8 min; p < 0.05). NECA decreased the core body temperature (T core ), oxygen consumption, which is an index of heat production, tail skin temperature, which is an index of heat loss, and extracellular dopamine (DA) release at rest and during exercise. Furthermore, caffeine injection inhibited the NECA-induced decreases in the RTTF, T core , heat production, heat loss, and extracellular DA release. Neither caffeine nor NECA affected extracellular noradrenaline or serotonin release. These results support the findings of previous studies showing improved endurance performance and overrides in body limitations after caffeine administration, and imply that the ergogenic effects of caffeine may be associated with the adenosine receptor blockade-induced increases in brain DA release. [ABSTRACT FROM AUTHOR]

Position statement: The International Society of Sports Nutrition (ISSN) provides an objective and critical review of the mechanisms and use of beta-alanine supplementation. Based on the current available literature, the conclusions of the ISSN are as follows: 1) Four weeks of beta-alanine supplementation (4–6 g daily) significantly augments muscle carnosine concentrations, thereby acting as an intracellular pH buffer; 2) Beta-alanine supplementation currently appears to be safe in healthy populations at recommended doses; 3) The only reported side effect is paraesthesia (tingling), but studies indicate this can be attenuated by using divided lower doses (1.6 g) or using a sustained-release formula; 4) Daily supplementation with 4 to 6 g of beta-alanine for at least 2 to 4 weeks has been shown to improve exercise performance, with more pronounced effects in open end-point tasks/time trials lasting 1 to 4 min in duration; 5) Beta-alanine attenuates neuromuscular fatigue, particularly in older subjects, and preliminary evidence indicates that beta-alanine may improve tactical performance; 6) Combining beta-alanine with other single or multi-ingredient supplements may be advantageous when supplementation of beta-alanine is high enough (4–6 g daily) and long enough (minimum 4 weeks); 7) More research is needed to determine the effects of beta-alanine on strength, endurance performance beyond 25 min in duration, and other health-related benefits associated with carnosine. [ABSTRACT FROM AUTHOR]

Objectives Inhaled β 2 -agonists may cause differential effects on lung function and athletic performance in female compared to male athletes. The objective of this study was to compare the effects of inhaled β 2 -agonists on lung function and cycling performance between female athletes with and without exercise-induced bronchoconstriction and with previously published data on men. Design Double-blind crossover randomized controlled trial. Methods Twenty-one female athletes (6 with exercise-induced bronchoconstriction and 15 without exercise-induced bronchoconstriction) performed a simulated 10-km time-trial on a cycle ergometer 60 min after the inhalation of either 400 μg of salbutamol or placebo. Forced expiratory volume in 1 s, was measured immediately before and 30 min after inhalation. Performance was measured by mean power output over the duration of the time trial. Results After salbutamol inhalation, Forced expiratory volume in 1 s improved significantly in athletes with exercise-induced bronchoconstriction (M (SD) = 6.1% (47.6)) and athletes without exercise-induced bronchoconstriction (4.0% (3.1); p ≤ 0.02). Mean power output was significantly decreased after salbutamol use (204 W (21)) compared to placebo (208 W (17); p = 0.047), regardless of airway hyperresponsiveness. Relative to placebo, salbutamol significantly increased mean oxygen consumption (46.9 mL kg −1 min −1 (5.9) vs. 44.8 mL kg −1 min −1 (4.0); p = 0.049) and significantly decreased cycling economy (72.8 W L −1 min −1 (6.8) vs. 76.4 W L −1 min −1 (4.3); p = 0.01). Conclusions The inhalation of salbutamol induced a significant increase in lung function in female athletes, but this increased lung function did not translate to improved exercise performance. [ABSTRACT FROM AUTHOR]

The study examined the effect of caffeine supplementation on match activities and development of fatigue during a football match. In a randomised, double-blind cross-over design, two experimental football games separated by 7 days were organised between the junior teams of two professional football clubs (17.6 ± 1.1 years (±s), 71.7 ± 6.9 kg, 13.9% ± 5.0% body fat). The players ingested either a capsule of 6 mg · kg−1 b.w. caffeine or placebo (dextrose) 65 min prior to the matches. Match activities were assessed using the ZXY match analysis system, and a Yo-Yo intermittent recovery test–level 2 (Yo-Yo IR2) was conducted immediately post-game. Heart rate was monitored throughout the game, and blood samples were obtained at baseline, half-time and after the game. There were no differences between caffeine and placebo regarding total distance covered (10,062 ± 916 vs 9854 ± 901 m), high-intensity running (557 ± 178 vs 642 ± 240 m), sprinting distance (109 ± 58 vs 112 ± 69 m) or acceleration counts (123 ± 31 vs 126 ± 24). In both trials, players displayed lower (P < 0.05) values in total distance and acceleration counts in the last 15 min compared to all other 15-min periods of the matches. Post-game Yo-Yo IR2 performance was not different between game trials (caffeine: 829 ± 322 m; placebo 819 ± 289 m). In conclusion, oral caffeine administration does not appear to have an ergogenic effect in young football players during match play. [ABSTRACT FROM AUTHOR]

The purpose of this study was to examine changes of thermoregulation, neurotransmitters in the preoptic area and anterior hypothalamus (PO/AH), which is the thermoregulatory center, and endurance exercise performance after the intraperitoneal injection of caffeine in rats. Core body temperature (Tcore), oxygen consumption (VO2) and tail skin temperature (Ttail) were measured. A microdialysis probe was inserted in the PO/AH, and samples for the measurements of extracellular dopamine (DA), noradrenaline (NA) and serotonin (5-HT) levels were collected. During the rest experiment, 1h after baseline collections in the chamber (23°C), the rats were intraperitoneally injected with saline, or 3mgkg−1 or 10mgkg−1 caffeine. The duration of the test was 4h. During the exercise experiment, baseline collections on the treadmill were obtained for 1h. One hour before the start of exercise, rats were intraperitoneally injected with either 10mgkg−1 caffeine (CAF) or saline (SAL). Animals ran until fatigue at a speed of 18mmin−1, at a 5% grade, on the treadmill in a normal environment (23°C). At rest, 3mgkg−1 caffeine did not influence Tcore, Ttail, VO2, extracellular DA, NA and 5-HT. 10mgkg−1 caffeine caused significant increases in Tcore, VO2, Ttail and extracellular DA in the PO/AH. In addition, 10mgkg−1 caffeine increased the run time to fatigue (SAL: 104.4±30.9min, CAF: 134.0±31.1min, p<0.05). The combination of caffeine and exercise increased Tcore, VO2, Ttail and extracellular DA in the PO/AH. NA increased during exercise, while neither caffeine nor exercise changed 5-HT. These results indicate that caffeine has ergogenic and hyperthermic effects, and these effects may be related to changes of DA release in the brain. [ABSTRACT FROM AUTHOR]

Capsiate is known to increase whole body oxygen consumption possibly via the activation of uncoupling processes, but its effect at the skeletal muscle level remains poorly documented and conflicting. To clarify this issue, gastrocnemius muscle function and energetics were investigated in mice 2 h after a single intake of either vehicle (control) or purified capsiate (at 10 or 100 mg/kg body wt) through a multidisciplinary approach combining in vivo and in vitro measurements. Mechanical performance and energy pathway fluxes were assessed strictly noninvasively during a standardized electrostimulation-induced exercise, using an original device implementing 31-phosphorus magnetic resonance spectroscopy, and mitochondrial respiration was evaluated in isolated saponin-permeabilized fibers. Compared with control, both capsiate doses produced quantitatively similar effects at the energy metabolism level, including an about twofold decrease of the mitochondrial respiration sensitivity for ADP. Interestingly, they did not alter either oxidative phosphorylation or uncoupling protein 3 gene expression at rest. During 6 min of maximal repeated isometric contractions, both doses reduced the amount of ATP produced from glycolysis and oxidative phosphorylation but increased the relative contribution of oxidative phosphorylation to total energy turnover (+28 and +21% in the 10- and 100-mg groups, respectively). ATP cost of twitch force generation was further reduced in the 10- (-35%) and 100-mg (-45%) groups. Besides, the highest capsiate dose also increased the twitch force-generating capacity. These data present capsiate as a helpful candidate to enhance both muscle performance and oxidative phosphorylation during exercise, which could constitute a nutritional approach for improving health and preventing obesity and associated metabolic disorders. [ABSTRACT FROM AUTHOR]