A Narrative Review of Current Concerns and Future Perspectives of the Carbohydrate Mouth Rinse Effects on Exercise Performance.

Previous systematic reviews have confirmed that carbohydrate (CHO) mouth rinse may boost physical exercise performance, despite some methodological aspects likely affecting its ergogenic effect. In this review, we discussed if the exercise mode, pre-exercise fasting status, CHO solutions concentration, CHO solutions temperature, mouth rinse duration, and CHO placebo effects may potentially reduce the CHO mouth rinse ergogenic effect, suggesting possible solutions to manage these potential confounders. The effectiveness of CHO mouth rinse as a performance booster is apparently related to the origin of the exercise-induced neuromuscular fatigue, as CHO mouth rinse unequivocally potentiates endurance rather than sprint and strength exercises performance. Furthermore, ergogenic effects have been greater in fasting than fed state, somehow explaining the varied magnitude of the CHO mouth rinse effects in exercise performance. In this regard, the CHO solution concentration and temperature, as well as the mouth rinse duration, may have increased the variability observed in CHO mouth rinse effects in fasting and fed state. Finally, placebo effects have challenged the potential of the CHO mouth rinse as an ergogenic aid. Therefore, we suggest that future studies should consider methodological controls such as sample size and sample homogeneity, proper familiarization with experimental procedures, and the use of alternative placebo designs to provide unbiased evidence regarding the potential of the CHO mouth rinse as an ergogenic aid.

Perceptual and Neuromuscular Responses Adapt Similarly Between High-Load Resistance Training and Low-Load Resistance Training With Blood Flow Restriction.

ABSTRACT: Teixeira, EL, Painelli, VdS, Schoenfeld, BJ, Silva-Batista, C, Longo, AR, Aihara, AY, Cardoso, FN, Peres, BdA, and Tricoli, V. Perceptual and neuromuscular responses adapt similarly between high-load resistance training and low-load resistance training with blood flow restriction. J Strength Cond Res 36(9): 2410-2416, 2022-This study compared the effects of 8 weeks of low-load resistance training with blood flow restriction (LL-BFR) and high-load resistance training (HL-RT) on perceptual responses (rating of perceived exertion [RPE] and pain), quadriceps cross-sectional area (QCSA), and muscle strength (1 repetition maximum [RM]). Sixteen physically active men trained twice per week, for 8 weeks. One leg performed LL-BFR (3 sets of 15 repetitions, 20% 1RM), whereas the contralateral leg performed HL-RT (3 sets of 8 repetitions, 70% 1RM). Rating of perceived exertion and pain were evaluated immediately after the first and last training sessions, whereas QCSA and 1RM were assessed at baseline and after training. Rating of perceived exertion was significantly lower (6.8 ± 1.1 vs. 8.1 ± 0.8, p = 0.001) and pain significantly higher (7.1 ± 1.2 vs. 5.8 ± 1.8, p = 0.02) for LL-BFR than that for HL-RT before training. Significant reductions in RPE and pain were shown for both protocols after training (both p < 0.0001), although no between-protocol differences were shown in absolute changes ( p = 0.10 and p = 0.48, respectively). Both LL-BFR and HL-RT were similarly effective in increasing QCSA (7.0 ± 3.8% and 6.3 ± 4.1%, respectively; both p < 0.0001) and 1RM (6.9 ± 4.1% and 13.7 ± 5.9%, respectively; both P < 0.0001), although absolute changes for 1RM in HL-RT were greater than LL-BFR ( p = 0.001). In conclusion, LL-BFR produces lower RPE values and a higher pain perception than HL-RT. However, consistent application of these approaches result in chronic adaptations so that there are no differences in perceptual responses over the course of time. In addition, muscle strength is optimized with HL-RT despite similar increases in muscle hypertrophy between conditions.

Carbohydrate Mouth Rinse Mitigates Mental Fatigue Effects on Maximal Incremental Test Performance, but Not in Cortical Alterations.

Detrimental mental fatigue effects on exercise performance have been documented in constant workload and time trial exercises, but effects on a maximal incremental test (MIT) remain poorly investigated. Mental fatigue-reduced exercise performance is related to an increased effort sensation, likely due to a reduced prefrontal cortex (PFC) activation and inhibited spontaneous behavior. Interestingly, only a few studies verified if centrally active compounds may mitigate such effects. For example, carbohydrate (CHO) mouth rinse potentiates exercise performance and reduces effort sensation, likely through its effects on PFC activation. However, it is unknown if this centrally mediated effect of CHO mouth rinse may mitigate mental fatigue-reduced exercise performance. After a proof-of-principle study, showing a mental fatigue-reduced MIT performance, we observed that CHO mouth rinse mitigated MIT performance reductions in mentally fatigued cyclists, regardless of PFC alterations. When compared to placebo, mentally fatigued cyclists improved MIT performance by 2.24-2.33% when rinsing their mouth with CHO during MIT. However, PFC and motor cortex activation during MIT in both CHO and placebo mouth rinses were greater than in mental fatigue. Results showed that CHO mouth rinse mitigated the mental fatigue-reduced MIT performance, but challenged the role of CHO mouth rinse on PFC and motor cortex activation.

Magnetic Resonance Spectroscopy as a Non-invasive Method to Quantify Muscle Carnosine in Humans: a Comprehensive Validity Assessment.

Carnosine is a dipeptide abundantly found in human skeletal muscle, cardiac muscle and neuronal cells having numerous properties that confers performance enhancing effects, as well as a wide-range of potential therapeutic applications. A reliable and valid method for tissue carnosine quantification is crucial for advancing the knowledge on biological processes involved with carnosine metabolism. In this regard, proton magnetic resonance spectroscopy (1H-MRS) has been used as a non-invasive alternative to quantify carnosine in human skeletal muscle. However, carnosine quantification by 1H-MRS has some potential limitations that warrant a thorough experimental examination of its validity. The present investigation examined the reliability, accuracy and sensitivity for the determination of muscle carnosine in humans using in vitro and in vivo experiments and comparing it to reference method for carnosine quantification (high-performance liquid chromatography - HPLC). We used in vitro 1H-MRS to verify signal linearity and possible noise sources. Carnosine was determined in the m. gastrocnemius by 1H-MRS and HPLC to compare signal quality and convergent validity. 1H-MRS showed adequate discriminant validity, but limited reliability and poor agreement with a reference method. Low signal amplitude, low signal-to-noise ratio, and voxel repositioning are major sources of error.

A suplementação com vitamina C e E pode inibir as adaptações ao treinamento físico aeróbio? / Does vitamin C and E supplementation inhibit aerobic exercise training adaptations?

Cronicamente, o exercício aeróbio promove inúmeros benefícios sobre o desempenho físico e a saúde. No entanto, sessões agudas de exercício aeróbio induzem a produção de Radicais Livres, cujo acúmulo está associado a diversos efeitos prejudiciais sobre a célula, e em última instância, sobre a saúde. Apesar da existência de defesas antioxidantes nas células musculares, e da sugestão de que a presença dos Radicais Livres funcionaria como um importante gatilho para algumas adaptações ao treinamento físico, é crescente o número de trabalhos investigando se a suplementação com antioxidantes, tais como as Vitaminas C e E, pode atenuar o surgimento dos Radicais Livres produzidos durante o exercício e treinamento aeróbio. É igualmente crescente o número de estudos averiguando se a suplementação com antioxidantes poderia interferir com certas adaptações ao treinamento aeróbio. Logo, o objetivo deste Ponto de Vista foi examinar se as evidências literárias permitem concluir se a suplementação com antioxidantes inibe a adaptação das defesas antioxidantes endógenas, de fatores relacionados ao conteúdo e função mitocondriais, e do consumo máximo de oxigênio. Observou-se escassez e controvérsia entre os diferentes estudos, onde fatores relacionados ao baixo número amostral, ao curto período de exposição aos protocolos de treinamento, e à ausência de padronização nas medidas fisiológicas sendo mensuradas bem como da caracterização do estado antioxidante basal ainda causam dificuldade no estabelecimento de conclusões definitivas. Entretanto, as poucas evidências oriundas de estudos bem controlados sugerem que algumas adaptações, em especial aquelas relacionadas à biogênese e atividade mitocondrial, podem ser inibidas com a adição das Vitaminas C e/ou E ao treinamento aeróbio...(AU)

Chronically, aerobic exercise promotes several benefits on exercise performance and health. However, acute sessions of aerobic exercise induce the production of Free Radicals, which accumulation is associated with several harmful effects on the cell, and ultimately on health. Despite the existence of antioxidant defenses within muscle cells, and the suggestion that the presence of Free Radicals would act as an important trigger for some adaptations to exercise training, there is a growing number of studies investigating whether supplementation with antioxidants, such as Vitamins C and E, can attenuate the occurrence of Free Radicals produced during exercise and aerobic training. The number of studies investigating whether antioxidant supplementation could interfere with certain adaptations to aerobic training is also increasing. Therefore, the aim of this Point of View was to examine whether evidence allow us to conclude if antioxidant supplementation inhibits the adaptation of endogenous antioxidant defenses, factors related to mitochondrial content and function, and maximal oxygen uptake. It was observed scarcity and controversy among the different studies, where factors related to the low sample size, the short period of exposure to the training protocols, and the lack of standardization in the physiological measures being measured as well as of the characterization of the basal antioxidant status still cause difficulty in establishing definitive conclusions. However, the few evidence from well-controlled studies suggest that some adaptations, especially those related to mitochondrial biogenesis and activity, may be inhibited with the addition of Vitamins C and/or E to aerobic training...(AU)

A Systematic Risk Assessment and Meta-Analysis on the Use of Oral ß-Alanine Supplementation.

ß-Alanine supplementation is one of the world's most commonly used sports supplements, and its use as a nutritional strategy in other populations is ever-increasing, due to evidence of pleiotropic ergogenic and therapeutic benefits. Despite its widespread use, there is only limited understanding of potential adverse effects. To address this, a systematic risk assessment and meta-analysis was undertaken. Four databases were searched using keywords and Medical Subject Headings. All human and animal studies that investigated an isolated, oral, ß-alanine supplementation strategy were included. Data were extracted according to 5 main outcomes, including 1) side effects reported during longitudinal trials, 2) side effects reported during acute trials, 3) effect of supplementation on circulating health-related biomarkers, 4) effect of supplementation on skeletal muscle taurine and histidine concentration, and 5) outcomes from animal trials. Quality of evidence for outcomes was ascertained using the Grading of Recommendations Assessment Development and Evaluation (GRADE) framework, and all quantitative data were meta-analyzed using multilevel models grounded in Bayesian principles. In total, 101 human and 50 animal studies were included. Paraesthesia was the only reported side effect and had an estimated OR of 8.9 [95% credible interval (CrI): 2.2, 32.6] with supplementation relative to placebo. Participants in active treatment groups experienced similar dropout rates to those receiving the placebo treatment. ß-Alanine supplementation caused a small increase in circulating alanine aminotransferase concentration (effect size, ES: 0.274, CrI: 0.04, 0.527), although mean data remained well within clinical reference ranges. Meta-analysis of human data showed no main effect of ß-alanine supplementation on skeletal muscle taurine (ES: 0.156; 95% CrI: -0.38, 0.72) or histidine (ES: -0.15; 95% CrI: -0.64, 0.33) concentration. A main effect of ß-alanine supplementation on taurine concentration was reported for murine models, but only when the daily dose was ≥3% ß-alanine in drinking water. The results of this review indicate that ß-alanine supplementation within the doses used in the available research designs, does not adversely affect those consuming it.

A temperatura dos repositores hídricos pode influenciar a capacidade aeróbia? / Does the fluid replacers' temperature may influence the aerobic capacity?

O aumento da temperatura interna (Ti) é considerado importante causa da fadiga durante exercícios prolongados realizados no calor. Dentre as estratégias empregadas para atenuá-la, a reposição hídrica é a que mais se destaca por sua praticidade e baixo custo. Por outro lado, pouco se sabe a respeito da influência que a temperatura dos repositores hídricos exerce sobre respostas termorregulatórias e o desempenho aeróbio durante exercícios prolongados em ambientes quentes. Teoricamente, as bebidas em baixa temperatura poderiam conferir vantagem fisiológica, agindo como dissipadores de calor ou proporcionando uma sensação agradável, levando à manutenção da ativação do drive central. Combinados, esses mecanismos podem diminuir os efeitos deletérios da elevação da Ti ao desempenho. Mesmo assim, o número de estudos investigando tal hipótese é escasso. Logo, o objetivo deste Ponto de Vista foi examinar se as evidências existentes apoiam a hipótese de modulação da Ti e melhora do desempenho aeróbio a partir da ingestão de bebidas em baixas temperaturas durante os exercícios prolongados realizados no calor. Encontramos grande heterogeneidade na metodologia dos estudos, sobretudo no que diz respeito 1) ao baixo número amostral; 2) à ausência de soluções controle; 3) à falta de padronização do momento de administração dos repositores hídricos; e 4) ao protocolo de exercício utilizado. Isso dificulta o estabelecimento de conclusões definitivas sobre o assunto, e, portanto, mais estudos são necessários. Contudo, evidências oriundas de poucos estudos bem controlados sugerem que repositores hídricos em baixa temperatura podem atenuar o aumento na Ti e melhorar a capacidade aeróbia durante a realização de exercícios prolongados no calor....(AU)

The increase in internal temperature (Ti) is considered a major cause of fatigue during prolonged exercise in the heat. Among the strategies employed to attenuate it, the fluid replacement is the most used due its cost-effectiveness and practicality. On the other hand, little is known about the influence that the beverage temperature exerts on the thermoregulatory responses and aerobic capacity during prolonged exercise in hot environments. Theoretically, fluid replacers at a low temperature may provide a physiological advantage by acting as a 'heat sink', and providing a pleasant sensation, leading to increased central drive activation. These mechanisms would mitigate the side effects of an increased Ti on performance. Nevertheless, the number of studies dedicated to investigate this hypothesis is scarce. Thus, the aim of this Point of View was to examine whether the existing evidence support the modulation of Ti and improved aerobic capacity hypothesis from fluid replacers at low temperatures during prolonged exercise in hot environments. We have found substantial heterogeneity in the methodology inherent in these studies with regards to the 1) low sample size; 2) absence of control solutions; 3) lack of standardization of the moment of administration of the fluid replacers; and 4) exercise protocol. This causes difficulty in establishing definitive conclusions on this topic, and therefore more studies are required. However, the few existing evidence from well-controlled studies suggest that the fluid replacers at low temperatures can attenuate the increase in Ti and improve aerobic capacity during prolonged exercise in the heat....(AU)

Dispelling the myth that habitual caffeine consumption influences the performance response to acute caffeine supplementation.

This study investigates the influence of habitual caffeine intake on aerobic exercise-performance responses to acute caffeine supplementation. A double-blind, crossover, counterbalanced study was performed. Forty male endurance-trained cyclists were allocated into tertiles, according to their daily caffeine intake: low (58 ± 29 mg/d), moderate (143 ± 25 mg/d), and high (351 ± 139 mg/d) consumers. Participants completed three trials in which they performed simulated cycling time trials (TTs) in the fastest time possible following ingestion of the following: caffeine (CAF: 6 mg/kg body mass), placebo (PLA), and no supplement (CON). A mixed-model analysis revealed that TT performance was significantly improved in CAF compared with PLA and CON (29.92 ± 2.18 vs. 30.81 ± 2.67 and 31.14 ± 2.71 min, respectively; P = 0.0002). Analysis of covariance revealed no influence of habitual caffeine intake as a covariate on exercise performance (P = 0.47). TT performance was not significantly different among tertiles (P = 0.75). No correlation was observed between habitual caffeine intake and absolute changes (CAF - CON) in TT performance with caffeine (P = 0.524). Individual analysis showed that eight, seven, and five individuals improved above the variation of the test in CAF in the low, moderate, and high tertiles, respectively. A Fisher's exact test did not show any significant differences in the number of individuals who improved in CAF among the tertiles (P > 0.05). Blood lactate and ratings of perceived exertion were not different between trials and tertiles (P > 0.05). Performance effects of acute caffeine supplementation during an ~30-min cycling TT performance were not influenced by the level of habitual caffeine consumption.NEW & NOTEWORTHY There has been a long-standing paradigm that habitual caffeine intake may influence the ergogenicity of caffeine supplementation. Low, moderate, and high caffeine consumers showed similar absolute and relative improvements in cycling time-trial performance following acute supplementation of 6 mg/kg body mass caffeine. Performance effects of acute caffeine were not influenced by the level of habitual caffeine consumption, suggesting that high habitual caffeine intake does not negate the benefits of acute caffeine supplementation.

Nutritional Strategies to Modulate Intracellular and Extracellular Buffering Capacity During High-Intensity Exercise.

Intramuscular acidosis is a contributing factor to fatigue during high-intensity exercise. Many nutritional strategies aiming to increase intra- and extracellular buffering capacity have been investigated. Among these, supplementation of beta-alanine (~3-6.4 g/day for 4 weeks or longer), the rate-limiting factor to the intramuscular synthesis of carnosine (i.e. an intracellular buffer), has been shown to result in positive effects on exercise performance in which acidosis is a contributing factor to fatigue. Furthermore, sodium bicarbonate, sodium citrate and sodium/calcium lactate supplementation have been employed in an attempt to increase the extracellular buffering capacity. Although all attempts have increased blood bicarbonate concentrations, evidence indicates that sodium bicarbonate (0.3 g/kg body mass) is the most effective in improving high-intensity exercise performance. The evidence supporting the ergogenic effects of sodium citrate and lactate remain weak. These nutritional strategies are not without side effects, as gastrointestinal distress is often associated with the effective doses of sodium bicarbonate, sodium citrate and calcium lactate. Similarly, paresthesia (i.e. tingling sensation of the skin) is currently the only known side effect associated with beta-alanine supplementation, and it is caused by the acute elevation in plasma beta-alanine concentration after a single dose of beta-alanine. Finally, the co-supplementation of beta-alanine and sodium bicarbonate may result in additive ergogenic gains during high-intensity exercise, although studies are required to investigate this combination in a wide range of sports.

Can leucine supplementation attenuate muscle atrophy? A literature review / A suplementação de leucina pode atenuar a atrofia muscular? Uma revisão da literatura

Abstract Currently, there has been new expectations in studying strategies with the potential to mitigate the skeletal muscle atrophy that characterizes conditions such as aging, disuse, cancer, and the use of certain medications. Among them, amino acid leucine has received special attention due to its potential to stimulate specific pathways of protein synthesis in skeletal muscle. Due to the wide spread use of this amino acid by the media, several studies have been aimed at investigating the possible effectiveness of leucine against skeletal muscle atrophy. As a result, this literature review was aimed to analyze recent studies that investigated the effects of leucine supplementation on skeletal muscle atrophy in both humans and animals. Overall, the wide variations in the experimental designs developed, models studied, leucine dose, treatment duration and sample healthiness make it difficult for professionals and researchers to establish guidelines about possible therapeutic effectiveness of this nutritional strategy.

Resumo Atualmente, surgem novas expectativas em estudar estratégias com o potencial de atenuar a atrofia muscular esquelética que caracteriza condições como o envelhecimento, o desuso, o câncer, assim como o uso de determinadas medicações. Dentre elas, o aminoácido leucina vem recebendo especial destaque devido ao seu potencial em estimular vias específicas de síntese proteica no músculo esquelético. Devido à grande disseminação do uso deste aminoácido pela mídia, diversas pesquisas vêm sendo desenvolvidas com foco na investigação de possível efetividade da leucina contra a atrofia muscular esquelética. Em virtude disso, essa revisão bibliográfica teve por objetivo analisar os estudos recentes que investigaram os efeitos da suplementação isolada de leucina sobre a atrofia muscular, tanto em humanos quanto em animais. De forma geral, as grandes variações nos desenhos experimentais desenvolvidos, nos modelos estudados, na dose de leucina empregada, na duração do protocolo de suplementação e na saudabilidade da amostra, fazem com que profissionais da área e pesquisadores sofram em poder estabelecer maiores diretrizes acerca da possível eficácia terapêutica desta estratégia nutricional.

Eficácia ergogênica da suplementação de cafeína sobre o desempenho de força? uma análise crítica / Ergogenic efficacy of caffeine supplementation on strength performance? a critical analysis

Fatores que melhoram as adaptações ao treino de força, especialmente os nutricionais, têm sido alvo de interesse de praticantes de treino de força. Devido aos já conhecidos mecanismos de ação da cafeína, pesquisas vêm sendo desenvolvidas com o intuito de investigar o potencial ergogênico da cafeína sobre o desempenho de força. Tais estudos, entretanto, são escassos, e seus resultados, controversos. Assim, o objetivo desta revisão foi trazer à tona os potenciais mecanismos de ação pelos quais a cafeína poderia exercer seu efeito ergogênico sobre o desempenho de força, avaliando o possível papel ergogênico da suplementação de cafeína sobre esta atividade. De forma geral, devido à grande heterogeneidade existente nos desenhos experimentais, ao variado nível de habituação ao consumo de cafeína, às divergências dos testes físicos empregados e na dieta precedente ao teste físico, não podemos atestar a favor da eficácia ergogênica deste suplemento nutricional sobre o desempenho de força.

Factors that improve the adaptations to strength training, especially the nutritional, have been the subject of interest from individuals practicing strength training. Due to known mechanisms of action of caffeine, studies have been undertaken in order to investigate the ergogenic potential of caffeine on strength performance. Such studies, however, are scarce, and their results controversial. Thus, the aim of this review was to bring out the potential mechanisms of action by which caffeine could exert its ergogenic effect on strength performance, evaluating the possible ergogenic role of caffeine on this activity. In general, due to the heterogeneity in experimental designs, to the varied level of habituation to the consumption of caffeine, to the differences in the physical test employed and diet preceding the physical test, we cannot attest the ergogenic effectiveness of this nutritional supplement on strength performance.

Lactato: de causa da fadiga a suplemento ergogênico? / Lactate: from cause of fatigue to ergogenic supplement?

Durante anos, pesquisadores inseridos na área de fisiologia do exercício apontaram para o lactato como o principal causador da fadiga durante exercícios de alta intensidade. Hoje, por outro lado, já existem diversos estudos demonstrando que o lactato per se não possui qualquer efeito sobre a fadiga neste tipo de exercício, mas que a acidose muscular, ocasionada pelo acúmulo de íons hidrogênio no interior da célula muscular, seria o fator limitante para o desempenho físico durante exercícios físicos de alta intensidade. Assim, estratégias com o objetivo de atenuar a queda do pH intramuscular, como a suplementação de beta-alanina e bicarbonato de sódio, têm se destacado no cenário esportivo. Embora anteriormente destacado como vilão durante esforços intensos, a suplementação de lactato vem recebendo especial atenção em anos recentes. A suplementação com este composto teoricamente pode aumentar os níveis sanguíneos de pH e bicarbonato, aumentando a capacidade de tamponamento extracelular, e por consequência, o desempenho físico. A suplementação com lactato também pode aumentar os níveis sanguíneos deste composto, aumentando sua disponibilidade como substrato para a gliconeogênese. Assim, estudos tem surgido com o intuito de avaliar a eficácia do lactato como tamponante e como substrato energético. Os poucos estudos até agora conduzidos, entretanto, não nos permitem atestar a eficácia ergogênica desta estratégia nutricional. A falta de estudos dose-resposta sobre as variáveis sanguíneas que caracterizam o mecanismo de ação do lactato, bem como de aplicação de testes físicos com baixo coeficiente de variação e boa validade externa exemplificam a necessidade de mais estudos investigando a eficácia ergogênica desta estratégia nutricional.

For years, researchers from the exercise physiology field pointed to lactate as the main cause of fatigue during high-intensity exercises. Today, however, there are several studies demonstrating that lactate per se does not have any effect on fatigue during this type of exercise, but muscle acidosis occasioned by hydrogen ions accumulation inside the muscle cell would be the limiting factor for performance during high-intensity exercises. Therefore strategies aiming to attenuate the decrease of intramuscular pH levels, like beta-alanine and sodium bicarbonate supplementation, have been prominent in the sports scenario. Although previously highlighted as a villain during high-intensity exercises, lactate supplementation has received special attention in recent years. Supplementation with this compound can theoretically increase blood pH and bicarbonate levels, increasing the extracellular buffering capacity, and hence, performance. Lactate supplementation can also increase lactate blood levels, increasing its availability as a substrate for gluconeogenesis. Thus, studies have arisen aiming to assess the effectiveness of lactate as a buffering agent and as an energy substrate. The few studies so far conducted, however, do not allow us to attest the ergogenic effectiveness of this nutritional strategy. The lack of dose-response studies on blood variables that characterize lactate mechanism of action, as well as the application of physical tests with a low coefficient of variation and good external validity exemplifies the need for further studies investigating the ergogenic effectiveness of this nutritional strategy.

The effects of two different doses of calcium lactate on blood pH, bicarbonate, and repeated high-intensity exercise performance.

We investigated the effects of low- and high-dose calcium lactate supplementation on blood pH and bicarbonate (Study A) and on repeated high-intensity performance (Study B). In Study A, 10 young, physically active men (age: 24 ± 2.5 years; weight: 79.2 ± 9.45 kg; height: 1.79 ± 0.06 m) were assigned to acutely receive three different treatments, in a crossover fashion: high-dose calcium lactate (HD: 300 mg · kg(-1) body mass), low-dose calcium lactate (LD: 150 mg · kg(-1) body mass) and placebo (PL). During each visit, participants received one of these treatments and were assessed for blood pH and bicarbonate 0, 60, 90, 120, 150, 180, and 240 min following ingestion. In Study B, 12 young male participants (age: 26 ± 4.5 years; weight: 82.0 ± 11.0 kg; height: 1.81 ± 0.07 m) received the same treatments of Study A. Ninety minutes after ingestion, participants underwent 3 bouts of the upper-body Wingate test and were assessed for blood pH and bicarbonate 0 and 90 min following ingestion and immediately after exercise. In Study A, both HD and LD promoted slight but significant increases in blood bicarbonate (31.47 ± 1.57 and 31.69 ± 1.04 mmol · L(-1, respectively) and pH levels (7.36 ± 0.02 and 7.36 ± 0.01, respectively), with no effect of PL. In Study B, total work done, peak power, mean power output were not affected by treatments. In conclusion, low- and high-dose calcium lactate supplementation induced similar, yet very discrete, increases in blood pH and bicarbonate, which were not sufficiently large to improve repeated high-intensity performance.

The ergogenic effect of beta-alanine combined with sodium bicarbonate on high-intensity swimming performance.

We investigated the effect of beta-alanine (BA) alone (study A) and in combination with sodium bicarbonate (SB) (study B) on 100- and 200-m swimming performance. In study A, 16 swimmers were assigned to receive either BA (3.2 g·day(-1) for 1 week and 6.4 g·day(-1) for 4 weeks) or placebo (PL; dextrose). At baseline and after 5 weeks of supplementation, 100- and 200-m races were completed. In study B, 14 were assigned to receive either BA (3.2 g·day(-1) for 1 week and 6.4 g·day(-1) for 3 weeks) or PL. Time trials were performed once before and twice after supplementation (with PL and SB), in a crossover fashion, providing 4 conditions: PL-PL, PL-SB, BA-PL, and BA-SB. In study A, BA supplementation improved 100- and 200-m time-trial performance by 2.1% (p = 0.029) and 2.0% (p = 0.0008), respectively. In study B, 200-m time-trial performance improved in all conditions, compared with presupplementation, except the PL-PL condition (PL-SB, +2.3%; BA-PL, +1.5%; BA-SB, +2.13% (p < 0.05)). BA-SB was not different from BA-PL (p = 0.21), but the probability of a positive effect was 78.5%. In the 100-m time-trial, only a within-group effect for SB was observed in the PL-SB (p = 0.022) and BA-SB (p = 0.051) conditions. However, 6 of 7 athletes swam faster after BA supplementation. The probability of BA having a positive effect was 65.2%; when SB was added to BA, the probability was 71.8%. BA and SB supplementation improved 100- and 200-m swimming performance. The coingestion of BA and SB induced a further nonsignificant improvement in performance.