Caffeine mouth rinse has no effects on anaerobic energy yield during a Wingate Test
Abstract
Background: The purpose was to investigate the effect of caffeine (CAF) mouth rinse on peak power (PP), mean power (MP), peak power relative to body mass (rel PP), mean power relative to body mass (rel MP), fatigue index (FI) and anaerobic contribution in the Wingate Test.
Methods: Ten healthy men (age: 24.8±3.7 years; body mass: 71.0±7.8 kg; height: 170±3 cm; body fat: 17.02±4.9%; VO2max: 44.15±5.5 ml·kg-1·min=) were recruited. A randomized, double-blind, cross-over design was employed. Participants were instructed to complete Wingate Test in the fastest time possible under 2 conditions: CAF (25 ml of mint syrup with 1.2% of CAF, equivalent to 300 mg of CAF) and placebo (PLA) (25 ml of mint syrup without CAF).
Results: There was no difference at PP (P=0.66), MP (P=0.16), rel PP (P=0.82), rel MP (P=0.18), FI (P=0.19), anaerobic alactic (P=0.71), anaerobic lactic (P=0.25), total energy expenditure (P=0.41) and peak plasma lactate concentration (P=0.57).
Conclusions: CAF mouth rinse did not increase peak power (PP), mean power (MP), peak power relative to body mass (rel PP), mean power relative to body mass (rel MP), Fatigue Index (FI) nor anaerobic contribution in the Wingate Test.
Corresponding Assessment Scenarios in Laboratory and on-Court Tests: Centrality Measurements by Complex Networks Analysis in Young Basketball Players
Abstract
Besides technical and tactical aspects, basketball matches involve high aerobic and anaerobic capacities, conferring the final performance of a team. Thus, the evaluation of physical and technical responses is an effective way to predict the performance of athletes. Field and laboratory tests have been used in sports. The first involving high ecological validity and low cost, and the second, greater control and accuracy but not easy application, considering the different preparation phases in a season. This study aimed, through complex networks analysis, to verify whether centrality parameters analysed from significant correlations behave similarly in distinct scenarios (laboratory and on-court), emphasizing aerobic and anaerobic physical parameters and technical performances. The results showed that, in a compelling analysis involving basketball athletes, the studied centralities (degree, betweenness, eigenvector and pagerank) revealed similar responses in both scenarios, which is widely attractive considering the greater financial economy and lower time when applying tests in the field.
Classical and contemporary theories on respiratory variables control during exercise: the road to a middle ground
Abstract
In their Viewpoint, Nicolò and colleagues (5) highlight the differential control of fR and VT above RCP, when considering the non-linear increase in VE during incremental exercise. The classical view for respiratory control tends to put all “eggs” in the acid-base control “basket”, while the current proposal (5) raises awareness to the contribution of mechanical afferent feedback and central command as fast regulators, primarily, of fRx. Critics towards both views would rely on the difficulty to isolate and quantify the effect of such inputs on a high external validity experimental design. For example, blood lactate concentration and muscle acidotic state are not synchronized (3), still, most data challenging the importance of acidotic inputs are based on exercise conditions known to improve disparity due to lactate shuttles and consumption (2). On the other hand, compelling evidence was brought up regarding the speed and importance of mechanical inputs as well as central control to fR during intermittent and high-intensity exercise (5), which should not be disregarded anymore. Still, during prolonged exercise, electromyography activity decreases, despite evidence of the growing VE and perception of fatigue (1,4). The importance of mechanical and metabolic inputs on respiratory control may be, therefore, dependent on exercise intensity and duration, and their predominance roles could shift as fatigue progresses. Exercise physiology scientists should take this into consideration, while making the separate presentation of fR and VT a common practice for most protocols involving exercise, adding muscle pH when possible, to help shed light on this issue.
Caffeine improves various aspects of athletic performance in adolescents independent of their 163 C > A CYP1A2 genotypes
Abstract
The purpose of this study was to investigate whether variations in 163 C > A CYP1A2 genotypes (rs 762 551) (AA, AC, and CC) modify the ergogenic effects of caffeine (CAF) on strength, power, muscular endurance, agility, and endurance in adolescent athletes. One hundred adolescents (age = 15 ± 2 years) were recruited. Participants ingested CAF (6 mg.kg−1) or placebo (PLA, 300 mg of cellulose) 1 hour before performing a sequence of physical tests: handgrip strength, vertical jumps, agility test, sit‐ups, push‐ups, and the Yo‐Yo intermittent recovery test level 1 (Yo‐Yo IR1). Compared to PLA, CAF enhanced (P < .05) sit‐up (CAF = 37 ± 9; PLA = 35 ± 8 repetitions) and push‐up repetitions (CAF = 26 ± 11; PLA = 24 ± 11 repetitions), and increased distance covered in Yo‐Yo IR1 test (CAF = 1010.4 ± 378.9; PLA = 903.2 ± 325.7 m). There was no influence of CAF on handgrip strength (CAF = 35.1 ± 8.9; PLA = 33.7 ± 8.7 kgf), countermovement jump height (CAF = 49.3 ± 12.6; PLA = 47.9 ± 13.8 cm), spike jump height (CAF = 54.2 ± 13.6; PLA = 52.9 ± 14.5 cm), and time in agility test (CAF = 15.8 ± 1.1; PLA = 15.9 ± 1.3 s, P > .05). When present, the ergogenic effect of CAF was not dependent of genotype. CAF improves muscular endurance and aerobic performance in adolescent athletes, regardless of their 163 C > A CYP1A2 genotype.
Caffeine mouth rinse enhances performance, fatigue tolerance and reduces muscle activity during moderate-intensity cycling
Abstract
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 noncaloric 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.
Anaerobic Threshold in Stand-up Paddle Comparison Between Direct and Alternative Methods
Abstract
The purpose of this study was to test the validity of alternative protocols, mean velocity during 30 minutes of continuous effort (V30min) and critical velocity (CV), to estimate the anaerobic threshold in stand-up paddle (SUP). Eight athletes performed: 3 maximal efforts at 400-, 500-, and 800-m distances to determine CV values, using the distance-time relationship; 3 efforts at 85, 90, and 100% of maximal 500-m effort to determine the velocity related to 3.5 mmol·L−1 of lactate, assumed as the onset of blood lactate accumulation (OBLA) and; a 30-minute continuous effort to determine the V30min. All evaluations were separated by 48 hours, with the athletes using their own boards and paddles in the water. No differences were observed between the OBLA (2.35 ± 0.13 m·s−1) and alternative methods (CV: 2.42 ± 0.20 m·s−1; p = 0.10 and V30min: 2.32 ± 0.13 m·s−1; p = 0.63). Although strong correlations were observed between the OBLA and alternative methods (CV: r = 0.84 and V30min: r = 0.94), the limits of agreement were higher in CV (±0.23 m·s−1) than V30min (±0.08 m·s−1). These results demonstrate that both the CV and V30min are valid to estimate the OBLA. In view of the specificity of SUP and the high levels of agreement, the use of the V30min is recommended to prescribe training intensities.
Physiological and technical demands of the small-sided and generic games in female
futsal players
Aim: This study aimed to compare the heart rate (HR) values and technical action frequencies during small-sided (SSG) and generic (GG) games in women futsal players. Methods: Six futsal players (age: 20.5 ± 7.4 years, height: 163.3 ± 16 cm, body mass: 57.95 ± 22 kg, maximum rate of oxygen consumption (VO2 max): 42.0 ± 9 ml.kg.min-1) performed two experimental conditions in two days separated for at least 72h of interval: (1) one set of 10 minutes of SSG, 3x3 players; and (2) one set of 10 minutes of GG, 4 (1 joker) x 4 (1 joker) players. During each experimental session, the subject’s HR values were monitored every 1 minute of play. Pass, shot, dribbling, driving, and disarmament was recorded during the games. Results: There was no difference between SSG and GG for HR average (p = 0.50). The HR values that were recorded at the first minute of GG were higher than SSG (p = 0.02). The HRmax in SSG and GG were equivalent to 91.9% and 90.8% of HRmax of the incremental test, respectively. Total technical actions was higher in SSG (+ 18.4%, p= 0.001) than GG. Pass was higher in the SSG (+16%; p= 0.01) in comparison to GG. Conclusion: Both models were higher than HRmax equivalent to AT velocity. The technical actions of the SSG were higher than GG, suggesting that the SSG model is a suitable technical and physiological stimulus for the development of female futsal players.
Acute metformin administration increases mean power and the early Power phase during a Wingate test in healthy male subjects
The present study tested the hypothesis that acute metformin would increase peak power measured during a Wingate test. Fourteen men (24 ± 6 years; 75.8 ± 10.2 kg; 177 ± 7 cm) participated in four test sessions, conducted in a crossover, counterbalanced, double-blind model. The first and second sessions consisted of anthropometric measurements and one Wingate test per day to assess test-retest reliability. In the last two sessions, the Wingate tests were performed on metformin (500 mg capsule, 1 hour before) or placebo (cellulose capsule, 1 hour before) condition. No differences were found between the placebo and metformin for peak power (1056.8 ± 215.8 W vs. 1095.2 ± 199.3 W, respectively; p = 0.24). Mean power (630.9 ± 87.8 W vs. 613.1 ± 94.8 W, respectively; p=0.01) and total work (18928 ± 2633 kJ vs. 18393 ± 2845 kJ, respectively; p = 0.01) in the metformin condition was higher than the placebo. The power were greater in metformin when compared to the placebo in moments 3 (p = 0.01), 4 (p = 0.01), 5 (p = 0.04), 6 (p = 0.04), 7 (p = 0.02), 8 (p = 0.03) and 9 (p = 0.01) seconds. There were no differences between conditions for the peak lactate (p = 0.08) and the rating of perceived exertion (p = 0.84). Acute metformin administration increased the early power phase and the mean power of a Wingate test.
International Summer School on Wearable Sensors in Sport
Department of Movement, Human and Health Sciences, University of Rome “Foro Italico”, Italy, 14-16 June 2021
2nd Prize - € 250,00
de Barros Sousa, Filipe Antonio – Federal University of Alagoas (UFAL/LACAE)
Two wearable devices suitability for monitoring the internal load from cycling exercise at different intensities: a pilot study
Effects of creatine and caffeine ingestion in combination on exercise performance: A systematic review
Creatine (CRE) and caffeine (CAF) have been used as ergogenic aids to improve exercise performance. The present study reviewed the current evidence supporting the additional use of CAF intake during or after the CRE loading on exercise performance. The search was carried out in eight databases, with the methodological quality of the studies assessed via the QualSyst tool. From ten studies that met the criteria for inclusion, six had strong, three moderate, and one weak methodological quality. CAF was ingested ∼1 h before the performance trial (5-7 mg.kg-1) after a CRE loading period (5-6 days with 0.3 g.kg-1.d-1) in five studies, with the combination CAF + CRE providing additional ergogenic effect compared to CRE alone in three of these studies. Furthermore, CAF was ingested daily during the CRE loading protocol in five studies, with CAF showing additive benefits compared to CRE alone only in one study (3 g.d-1 of CRE during 3 days + 6 mg.kg-1 of CAF for 3 days). The combination CAF + CRE seems to provide additional benefits to exercise performance when CAF is acutely ingested after a CRE loading. There is, however, no apparent benefit in ingesting CAF during a CRE loading period.
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The rating of perceived exertion is able to differentiate the post-matches metabolomic profile of elite U-20 soccer players
Purpose: The study aimed to assess the metabolic impact of elite Brazilian U-20 players using the rating of perceived exertion scale (RPE) to discriminate metabolomics sensitivity post-two soccer games separated by a short recovery interval.
Methods: Urine was collected immediately and then 20 h after two soccer matches of elite Brazilian U-20 players. RPE was collected after games. The spectra were pre-processed using TopSpin®3.2 software. Chenomx®software was used to identify metabolites in the urine through the available database.
Results: The results showed that the metabolic pathways related to energy production, cellular damage, and organic stresses were changed immediately after the game. 20 h after the games, antioxidant and anti-inflammatory pathways related to cell recovery were identified (e.g., gallic acid, ascorbate, and betaine). The matrix of positive correlations between metabolites was more predominant and stronger after game 2 than game 1. T-distribution registered metabolites discriminated below and above 7 on the RPE scale. Athletes with higher RPE values showed a high metabolite profile related to muscle damage (e.g., creatine, creatinine, and glycine) and energy production (e.g., creatine, formate, pyruvate, 1,3 dihydroxyacetone) 20 h post-soccer match. There was a different metabolic profile between athletes with higher and lower RPE values.
Conclusion: Metabolomics analysis made it possible to observe the metabolic impacts of energy production and muscular damage. RPE identified internal load changes within the group as a result of match intensity in soccer. The correlation matrix indicated a greater predominance of positive and strong correlations between metabolites in the second game compared to the first game.
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