Treinamento de força em circuito na perda e no controle do peso corporal

Muitos estudos têm sido feitos voltados para contribuir no combate a prevenção e diminuição do número de pessoas com excesso de peso corporal (gordura corporal). No qual o aumento do gasto calórico é fundamental. O treinamento de força em circuito pode ser um método de treinamento intermediário entre os exercícios com predominância aeróbia ou anaeróbia, que parece atender as pessoas com sobrepeso. Podendo ser um método mais intenso (com características mais anaeróbias) tendo uma maior presença do metabolismo aeróbio, contribuindo com um maior gasto calórico durante o exercício e na sua recuperação, através de um maior EPOC, totalizando em um maior gasto calórico durante as 24 horas do dia ao individuo

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

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

Leucine and HMB differentially modulate proteasome system in skeletal muscle under different sarcopenic conditions

In the present study we have compared the effects of leucine supplementation and its metabolite β-hydroxy-β-methyl butyrate (HMB) on the ubiquitin-proteasome system and the PI3K/Akt pathway during two distinct atrophic conditions, hindlimb immobilization and dexamethasone treatment. Leucine supplementation was able to minimize the reduction in rat soleus mass driven by immobilization. On the other hand, leucine supplementation was unable to provide protection against soleus mass loss in dexamethasone treated rats. Interestingly, HMB supplementation was unable to provide protection against mass loss in all treatments. While solely fiber type I cross sectional area (CSA) was protected in immobilized soleus of leucine-supplemented rats, none of the fiber types were protected by leucine supplementation in rats under dexamethasone treatment. In addition and in line with muscle mass results, HMB treatment did not attenuate CSA decrease in all fiber types against either immobilization or dexamethasone treatment. While leucine supplementation was able to minimize increased expression of both Mafbx/Atrogin and MuRF1 in immobilized rats, leucine was only able to minimize Mafbx/Atrogin in dexamethasone treated rats. In contrast, HMB was unable to restrain the increase in those atrogenes in immobilized rats, but in dexamethasone treated rats, HMB minimized increased expression of Mafbx/Atrogin. The amount of ubiquitinated proteins, as expected, was increased in immobilized and dexamethasone treated rats and only leucine was able to block this increase in immobilized rats but not in dexamethasone treated rats. Leucine supplementation maintained soleus tetanic peak force in immobilized rats at normal level. On the other hand, HMB treatment failed to maintain tetanic peak force regardless of treatment. The present data suggested that the anti-atrophic effects of leucine are not mediated by its metabolite HMB.State of São Paulo Research Foundation, FAPESP - 07/57613-3State of São Paulo Research Foundation, FAPESP - 12/13071-0State of São Paulo Research Foundation, FAPESP - 06/61523-7CNP

In vivo effects of two novel arylpyrazole glucocorticoid receptor modulators on skeletal muscle structure and function.

Neste estudo, testamos dois novos moduladores seletivos do receptor de glicocorticóide, nomeados L5 e L7, em comparação com o dexametasona, sobre aspectos estruturais, funcionais e moleculares no músculo sóleo. Ratos Wistar foram tratados com doses progressivas de dexametasona, L5 e L7 em 1 ou 7 dias. A massa corporal e a ingestão alimentar apresentaram queda após o tratamento com dexametasona em todas as doses; os tratamentos com L5/L7 mostraram resposta semelhante aos controles. O peso do músculo foi diminuído pelo dexametasona, efeito não observado nos tratamentos com L5/L7. Apenas o tratamento com dexametasona causou uma diminuição na área de secção transversa dos tipos de fibra muscular analisada. A força tetânica do sóleo foi diminuída pela dexametasona, nos tratamentos com L5/L7 este parâmetro também não foi afetado. A expressão gênica de MAFbx/Atrogin-1 e MuRF-1 foi elevada pela dexametasona; por outro lado, L5/L7 não elevaram a expressão destes genes. Concluímos que o L5/L7, em contraste com o dexametasona, preveniu o músculo esquelético da atrofia.In this study, we have tested two new selective modulators named L5 and L7 along with dexamethasone in skeletal muscle structural, functional and molecular aspects. Male Wistar rats were treated with progressive doses of dexamethasone, L5 and L7 for 1 and 7 days. While body weight and food intake were decreased by the dexamethasone treatment in all doses, L5/L7 treatments induced gain in body weight similarly to controls. Muscle weight was decreased by dexamethasone, while L5/L7 were ineffective. Only the dexamethasone treatment caused a decrease in the analyzed cross sectional area of the skeletal muscle fiber types. Soleus tetanic force was decreased by the dexamethasone treatment, while L5/L7 treatments did not alter this parameter. MAFbx/Atrogin-1 and MuRF-1 gene expressions were elevated by dexamethasone; on the other hand, L5/L7 did not modulate any expression of those genes. We conclude that L5/L7, in contrast to dexamethasone, spare skeletal muscle from structural and functional loss, and molecular changes, reinforcing their role as a therapeutic device

Polygenic profile of brazilian athletes: distribution of polymorphisms associated with physical performance

A partir da finalização do projeto genoma humano, fornecendo informação sobre o código genético de um indivíduo referência, pesquisadores direcionam a busca por sítios polimórficos existentes no DNA genômicos e mitocondrial capazes de influenciar direta ou indiretamente traços relevantes nas mais diversas áreas. No esporte esta busca tem sido direcionada para identificar marcadores genéticos associados aos fenótipos envolvidos com o desempenho físico (endurance vs. força e potência muscular). Atualmente, diversos polimorfismos foram associados ao desempenho físico-esportivo, em pelo menos um estudo. No entanto, como o rendimento desportivo é um fenômeno poligênico, ou seja, sob a regulação de vários genes, a associação de um polimorfismo é insuficiente para caracterizar o atleta. Hipóteses estão sendo desenvolvidas na tentativa de identificar o perfil poligênico (combinação de vários polimorfismos) em grupos de atletas. Alguns pesquisadores avaliaram o perfil poligênico preliminar de atletas europeus, analisando um conjunto de 7 a 10 polimorfismos, entretanto, esses achados precisam ser investigados em outras populações. O objetivo deste projeto foi traçar o perfil poligênico de atletas brasileiros. Para tanto, uma coorte brasileira envolvendo 342 atletas de endurance, 308 atletas de força e potência, 93 atletas de esportes coletivos, 165 atletas de lutas e 967 não atletas foi considerada neste estudo. O DNA genômico destes indivíduos foram extraídos e 34 polimorfismos foram genotipados. De uma forma geral, o grupo Endurance foi bem semelhante ao grupo Não atletas. Foi verificado que os polimorfismos AGT M235T - Alelo G, ACTN3 R577X - Alelo R, MCT1 D490E - Alelo T, PPARGC1A G482S - Alelo C, VEGFR2 Q472H - Alelo T, CNDP2 C/G - Alelo G e PPARA G/C - Alelo C podem ser considerados marcadores genéticos para atletas de atividades que envolvam a força e a potência muscular. Ainda, dos sete marcadores genéticos associados ao grupo Força/Potência, dois deles foram associados em coortes estrangeiras ao grupo Endurance, sugerindo que a população Brasileira pode apresentar associações específicas e diferenciadas. O escore total dos genótipos (TGS; modelo aditivo), utilizando os sete polimorfismos mais relevantes para a força e potência, foi eficiente em discriminar o grupo alvo, dos demais grupos. Foi observado que possuir uma quantidade >= 9 alelos associados (escore >= 64,3) aumentou significativamente a chance (76,8%) do indivíduo pertencer ao grupo Força/Potência. No entanto, existem atletas do grupo alvo, de destaque internacional (top atletas), que possuem um baixo número de alelos associados (2 a 4 alelos associados), bem como existem atletas de endurance que possuem um alto número de alelos associados (10 a 12 alelos associados). Possuir um número maior de alelos associados ao fenótipo alvo pode ser uma vantagem para o atleta, que precisa ser adequadamente estimulado por fatores ambientais. Contudo, uma associação genótipo-fenótipo não indica que o indivíduo pode antecipar uma carreira vitoriosa. O desempenho físico-esportivo reflete uma complexa interação de fatores ambientais ou sociaisAfter the conclusion of the human genome project, information about the genetic code of an individual (reference) was provided. Since then, scientists directed their research to identify polymorphic sites in genomic and mitochondrial DNA able to be associated with relevant phenotypes. In sports, the search has been directed to identify genetic markers associated with performance-related phenotypes (endurance vs. muscle strength and power phenotypes). Currently, many polymorphisms have been associated with physical performance in at least one study. However, as the sport performance is a polygenic phenomenon (i.e., under the regulation of several genes), the association of a single polymorphism is insufficient to characterize the athlete biology. Hypotheses are being developed in an attempt to identify the athlete polygenic profile (i.e., the combination of several sports-relevant polymorphisms). Some researchers evaluated a preliminary polygenic profile of European athletes by analyzing a range from 7 to 10 polymorphisms; however, these findings need to be investigated in other populations. The objective of this project was to explore the polygenic profile of Brazilian athletes. A Brazilian cohort involving 342 endurance athletes, 308 strength and power athletes, 93 athletes from team sports, 165 combat sports athletes and 967 non-athletes was evaluated. Genomic DNA of these individuals was extracted and 34 polymorphisms were genotyped. In general, the Endurance group was very similar to the Non-athlete group. The main associations were found when comparing the Strength/Power group with the Non-athlete group. Seven genetic markers were highlighted in the Strength/Power group. It was found that the following polymorphisms AGT M235T - Allele G, ACTN3 R577X - Allele R, MCT1 D490E - Allele T, PPARGC1A G482S - Allele C, VEGFR2 Q472H - Allele T, CNDP2 C/G - Allele G e PPARA G/C - Allele C can be considered genetic markers for Brazilian strength and power athletes. Of the seven genetic markers associated with Strength/Power, two were previously associated in other cohorts to Endurance, suggesting that the Brazilian population may have different and specific associations. The Total Genotype Score (TGS; additive model) using the seven most relevant polymorphisms was efficient to discriminate the Strength/Power group. It was observed that having a quantity >= 9 alleles associated (score >= 64.3) significantly increased the chance (76.8%) of belong to the Strength/Power group. However, there are some athletes of the Strength/Power group (international-level) showing a low number of associated alleles (2 to 4 associated alleles), as well as Endurance athletes showing a high number of associated alleles (10 to 12 associated alleles). A high number of associated alleles may be advantageous to the athlete; however they need to be properly stimulated by environmental factors. Any genotype-phenotype association does not indicate that an individual can anticipate a successful career. The athletic performance reflects a complex interaction of genetic and environmental / social factor