Is individualization of sodium bicarbonate ingestion based on time to peak necessary?

Purpose: To describe the reliability of blood bicarbonate pharmacokinetics in response to sodium bicarbonate (SB) supplementation across multiple occasions and assess, using putative thresholds, whether individual variation indicated a need for individualised ingestion timings. Methods: Thirteen men (age 27±5 y; body mass (BM) 77.4±10.5 kg; height 1.75±0.06 m) ingested 0.3 g·kg-1BM SB in gelatine capsules on 3 occasions. One hour after a standardised meal, venous blood was obtained before and every 10 min following ingestion for 3 h, then every 20 min for a further hour. Time-to-peak (Tmax), absolute-peak (Cmax), absolute-peak-change (ΔCmax) and area under the curve (AUC) were analysed using mixed models, intraclass correlation coefficient (ICC), coefficient of variation (CV) and typical error. Individual variation in pharmacokinetic responses was assessed using Bayesian simulation with multilevel models with random intercepts. Results: No significant differences between sessions were shown for blood bicarbonate regarding Cmax, ΔCmax or AUC (p>0.05), although Tmax occurred earlier in SB2 (127±36 min) than in SB1 (169±54 min, p=0.0088) and SB3 (159±42 min, p=0.05). ICC, CV and typical error showed moderate to poor reliability. Bayesian modelling estimated that >80% of individuals from the population experience elevated blood bicarbonate levels above + 5 mmol∙L-1 between 75-240 min after ingestion, and between 90-225 min above +6 mmol∙L-1. Conclusion: Assessing SB supplementation using discrete values showed only moderate reliability at the group level, and poor reliability at the individual level, while Tmax was not reproducible. However, when analysed as modelled curves, a 0.3 g·kg-1BM dose was shown to create a long-lasting window of ergogenic potential, challenging the notion that SB ingestion individualised to time-to-peak is a necessary strategy, at least when SB is ingested in capsules

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

supplementation and effects on performance

A vitamina D parece desempenhar papel importante na função muscular. A literatura aponta que níveis baixos dessa vitamina em atletas podem levar a maior risco de fratura por estresse, além de prejudicar a função e recuperação musculares. Esse trabalho objetiva identificar as implicações da deficiência de vitamina D no esporte, bem como analisar os efeitos da suplementação sobre níveis sanguíneos e performance atlética. Nesta revisão narrativa da literatura, uma busca por artigos científicos foi realizada nas bases de dados Pubmed e Biblioteca Virtual em Saúde (BVS). O papel da vitamina D está relacionado com saúde óssea, ação imunomoduladora, atuando sobre a imunidade inata e adquirida, inflamação, além de atuar em ações de vias moleculares nos músculos. Estudos mostram altas taxas de insuficiência e deficiência de vitamina D em atletas de diversas modalidades esportivas. Os níveis reduzidos dessa vitamina são observados principalmente em atletas que praticam modalidades esportivas do tipo indoor. Além disso, insuficiência e deficiência costumam ser mais frequentes nos meses de inverno. Apesar das taxas elevadas, a deficiência de vitamina D parece não impactar significativamente o desempenho de atletas. Estudos clínicos com diversos protocolos de suplementação de vitamina D em atletas apontam melhora considerável do estado nutricional dessa vitamina, porém ao analisar parâmetros de performance, essa melhora não é observada de forma significativa. Não há evidência de que a suplementação pode melhorar o desempenho em atletas. Logo, a vitamina D não deve ser recomendada como recurso ergogênico, mas para correção de deficiências e melhora da saúde geral dos atletas.Vitamin D seems to play an important role in muscle function. The literature points out that low levels of this vitamin in athletes can lead to a higher risk of stress fracture, in addition to impairing muscle function and recovery. This work aims to identify the implications of vitamin D deficiency in sport and to analyze the effects of supplementation on blood levels and athletic performance. In this narrative review of the literature, a search for scientific articles was carried out in Pubmed and Virtual Health Library (VHL) databases. The role of vitamin D is related to bone health, immunomodulatory action, acting on immunity, inflammation, in addition to acting on molecular pathway actions in muscles. Studies show high rates of vitamin D insufficiency and deficiency in athletes from different sports. The reduced levels of this vitamin are observed mainly in athletes who practice indoor sports. In addition, insufficiency and deficiency are more frequent in the winter months. Despite the high rates, vitamin D deficiency does not appear to significantly impact the performance of athletes. Clinical studies with several vitamin D supplementation protocols in athletes point to a considerable improvement in the nutritional status of this vitamin, however, when analyzing performance parameters, this improvement is not significantly observed. There is no evidence that supplementation can improve performance in athletes. Therefore, vitamin D should not be recommended as an ergogenic aid, but to correct deficiencies and improve the general health of athletes

Genetics and sport performance: current challenges and directions to the future

In recent years there has been a great progress in molecular biology techniques, which has facilitated the researches on influence of genetics on human performance. There are specific regions of DNA that can vary between individuals. Such variations (i.e., polymorphisms) may, in part, explain why some individuals have differentiated responses to certain stimuli, including the responses to sports training. In a particular sport, the presence of specific polymorphisms may contribute to high levels of performance. Since 1998, several polymorphisms have been associated with athletic phenotypes; however the accumulation of information generated over these 15 years shows that the influence of genetics to sport is extremely complex. In this review, we will summarise the current status of the field, discussing the implications of available knowledge for the practice of professionals involved with the sport and suggesting future directions for research. We also discuss topics related to the importance of polygenic profile characterization of athletes, methods for the identification of new polymorphisms associated with physical performance, the use of genetic testing for predicting competitive success, and how crucial is the genetic profile for the success athletes in competition.In recent years there has been a great progress in molecular biology techniques, which has facilitated the researches on influence of genetics on human performance. There are specific regions of DNA that can vary between individuals. Such variations (i.e., polymorphisms) may, in part, explain why some individuals have differentiated responses to certain stimuli, including the responses to sports training. In a particular sport, the presence of specific polymorphisms may contribute to high levels of performance. Since 1998, several polymorphisms have been associated with athletic phenotypes; however the accumulation of information generated over these 15 years shows that the influence of genetics to sport is extremely complex. In this review, we will summarise the current status of the field, discussing the implications of available knowledge for the practice of professionals involved with the sport and suggesting future directions for research. We also discuss topics related to the importance of polygenic profile characterization of athletes, methods for the identification of new polymorphisms associated with physical performance, the use of genetic testing for predicting competitive success, and how crucial is the genetic profile for the success athletes in competition

Weight loss in combat sports: physiological, psychological and performance effects

Abstract\ud \ud \ud \ud Background\ud \ud The present article briefly reviews the weight loss processes in combat sports. We aimed to discuss the most relevant aspects of rapid weight loss (RWL) in combat sports.\ud \ud \ud \ud Methods\ud \ud This review was performed in the databases MedLine, Lilacs, PubMed and SciELO, and organized into sub-topics: (1) prevalence, magnitude and procedures, (2) psychological, physiological and performance effects, (3) possible strategies to avoid decreased performance (4) organizational strategies to avoid such practices.\ud \ud \ud \ud Results\ud \ud There was a high prevalence (50%) of RWL, regardless the specific combat discipline. Methods used are harmful to performance and health, such as laxatives, diuretics, use of plastic or rubber suits, and sauna. RWL affects physical and cognitive capacities, and may increase the risk of death.\ud \ud \ud \ud Conclusion\ud \ud Recommendations during different training phases, educational and organizational approaches are presented to deal with or to avoid RWL.The authors would like to thank FAPESP for supporting the studies on rapid weight loss (grant # 2006/51293-4)

The Magnitude of Rapid Weight Loss and Rapid Weight Gain in Combat Sport Athletes Preparing for Competition: A Systematic Review

Combat sport athletes typically engage in a process called making weight, characterized by rapid weight loss (RWL) and subsequent rapid weight gain (RWG) in the days preceding competition. These practices differ across each sport, but no systematic comparison of the size of the changes in body mass exists. The aim was to determine the magnitude of RWL and RWG in combat sport athletes preparing for competition. The review protocol was preregistered with PROSPERO (CRD42017055279). In eligible studies, athletes prepared habitually with a RWL period ≤7 days preceding competition. An electronic search of EBSCOhost (CINAHL Plus, MEDLINE, and SPORTDiscus) and PubMed Central was performed up to July 2018. Sixteen full-text studies (total 4,432 participants; 156 females and 4,276 males) were included, providing data from five combat sports (boxing, judo, mixed martial arts, taekwondo, and wrestling). Three studies reported RWL and 14 studies reported RWG. Duration permitted for RWG ranged 3–32 hr. The largest changes in body mass occurred in two separate mixed martial arts cohorts (RWL: 7.4 ± 1.1 kg [∼10%] and RWG: 7.4 ± 2.8 kg [11.7% ± 4.7%]). The magnitude of RWG appears to be influenced by the type of sport, competition structure, and recovery duration permitted. A cause for concern is the lack of objective data quantifying the magnitude of RWL. There is insufficient evidence to substantiate the use of RWG as a proxy for RWL, and little data are available in females. By engaging in RWG, athletes are able to exploit the rules to compete up to three weight categories higher than at the official weigh-in

Sodium bicarbonate supplementation and the female athlete: A brief commentary with small scale systematic review and meta-analysis:Sodium bicarbonate use in women

Sodium bicarbonate (SB) is considered an effective ergogenic supplement for improving high-intensity exercise capacity and performance, although recent data suggests that women may be less amenable to its ergogenic effects than men. Currently, an apparent paucity of data on women means no consensus exists on whether women benefit from SB supplementation. The aim of the current study was to quantify the proportion of the published literature on SB supplementation that includes women, and to synthesise the evidence regarding its effects on blood bicarbonate and exercise performance in women by performing a systematic review and meta-analysis. Electronic searches of the literature were undertaken using three databases (MEDLINE, Embase, SPORTDiscus) to identify relevant articles. All meta-analyses were performed within a Bayesian framework. A total of 149 SB articles were identified, 11 of which contained individual group data for women. Results indicated a pooled blood bicarbonate increase of 7.4 [95%CrI: 4.2 to 10.4 mmol·L-1] following supplementation and a pooled standardised exercise effect size of 0.37 [95%CrI: -0.06 to 0.92]. The SB literature is skewed, with only 20% (30 studies) of studies employing female participants, of which only 11 studies (7.4%) provided group analyses exclusively in women. Despite the small amount of available data, results are consistent in showing that SB supplementation in women leads to large changes in blood bicarbonate and that there is strong evidence for a positive ergogenic effect on exercise performance that is likely to be small to medium in magnitude

Optimization of fast and simple real-time PCR-based method for genotyping the angiotensin converting enzyme-I I/D polymorphism

The insertion or deletion of 288 bp in intron 16 of the gene encoding for angiotensin converting enzyme-I (ACE) was the first genetic variant associated with physical performance and one of the most studied in the past 15 years. Carries of the deletion in one of its alleles may have higher enzyme activity, which may result in a greater vasoconstrictor response. These individuals may also better respond to strength and power training, as carriers of the insertion may have a greater propensity to respond better to the endurance training. Traditionally, to determine an individual genotype (I/I, I/D or D/D) the conventional PCR is the method used. This method involves the PCR reaction and then gel electrophoresis for the visualization of DNA bands indicating the genotype. For use this methodology on a large scale, as seen in association studies, such as those used to evaluate the influence of genetics in sport, this double process of conventional PCR is not time-effective. This paper aims to present an optimized, fast and efficient method for the genotyping of this polymorphism by real-time PCR, using genomic DNA samples collected from buccal cells. The method discussed in the text was originally proposed in 2001, but its original configuration has limitations in its methodology and uses much of the reagent. Thus, protocol variables such as primer concentration, reaction volume and the resolution of dissociation curve which indicates the genotypes were adjusted. After this adjustments the protocol remained effective with a reduced cost, suitable for use in large-scale studies involving genetic and sport.A inserção ou deleção de 288 pb no íntron 16 do gene que codifica a enzima conversora de angiotensina (ECA) foi a primeira variante genética associada com o desempenho físico e uma das mais estudadas nos últimos 15 anos. Carreadores da deleção em pelo menos um dos alelos, podem apresentar maior atividade enzimática, resultando em uma maior resposta vasoconstritora. Estes indivíduos podem também possuir uma melhor resposta ao treinamento de força e potência, assim como carreadores da inserção podem possuir uma melhor predisposição ao treinamento de endurance. Tradicionalmente, para determinar o genótipo do indivíduo (I/I, I/D ou D/D), o método utilizado é o PCR convencional. Este método envolve dois estágios; primeiramente a reação da PCR é realizada e depois o gel de agarose contendo o produto da PCR é submetido à eletroforese tornando possível visualizar por luz UV as bandas de DNA indicando o genótipo. Para o uso desta metodologia em larga escala, como no caso de estudos de associação, utilizados para avaliar a influência da genética no esporte, este duplo processo consumo muito tempo. Este artigo tem como objetivo apresentar um protocolo rápido e eficiente para a genotipagem deste polimorfismo por meio da PCR em tempo real, utilizando DNA genômico coletado de células bucais. O protocolo discutido no texto foi inicialmente proposto em 2001, contudo a sua configuração original apresenta limitações e utiliza uma quantidade grande de material. Variáveis do protocolo, tais como: concentração do primer, volume de reação e resolução da curva de dissociação que indica o genótipo foram ajustadas. Após este ajustamento, o protocolo permaneceu efetivo com uma quantidade reduzida de custo, adequado para o uso em estudos em larga-escala envolvendo genética e esporte

STUDENTS DROPOUT: COMPARISON BETWEEN STUDENTS SELECTED FOR SOCIAL ECONOMICAL CRITERIA AND FOR GENERAL KNOWLEDGE

The dropout problem is an important issue in every UNESP social prep course, focus of several types of reflection. The authors' experience in coordinating "Cursinho Desafio" (a course that prepares students to take the university entrance test) motivated them to investigate the social and economical factors that may be predictive of a student initially driven to abandon his studies, trying to identify causes that prevent or promote evasion of the students in these projects by comparing two different samples by means of access to the course. The escape of the students who enter using for social economical criteria doesn’t differ, per se, from the escape of other students. However, this study showed us that the student's support network is essential, and as difficulties that are added up to their permanence, there is increased evasion

Individual participant data meta-analysis provides no evidence of individual response variation in individuals supplementing with beta-alanine.

Currently, little is known about the extent of inter-individual variability in response to beta-alanine (BA) supplementation, nor what proportion of said variability can be attributed to external factors, or to the intervention itself (intervention response). To investigate this, individual participant data on the effect of BA supplementation on a high intensity cycling capacity test (CCT110%) were meta-analysed. Changes in time to exhaustion (TTE) and muscle carnosine (MCarn) were the primary and secondary outcomes. Multi-level distributional Bayesian models were used to estimate the mean and standard deviation of BA and placebo (PLA) group change scores. The relative sizes of group standard deviations were used to infer whether observed variation in change scores were due to intervention or non-intervention related effects. Six eligible studies were identified, and individual data were obtained from four of these. Analyses showed a group effect of BA supplementation on TTE (7.7[95%CrI:1.3 to 14.3 s]) and MCarn (18.1[95%CrI:14.5 to 21.9 mmol·kgDM-1]). A large intervention response variation was identified for MCarn (σ_IR= 5.8 [95%CrI: 4.2 to 7.4 mmol·kgDM-1]); however, equivalent change score standard deviations were shown for PLA (16.1[95%CrI:13.0 to 21.3 s]) and BA (15.9[95%CrI:13.0 to 20.0 s] conditions, with the probability that standard deviation was greater in PLA being 0.64. In conclusion, the similarity in observed change score standard deviations between groups for TTE indicates the source of variation is common and therefore unrelated to BA supplementation, likely originating instead from external factors, which may include, for example, nutritional intake, sleep patterns or training status