Effects of Diets Supplemented with Branched-Chain Amino Acids on the Performance and Fatigue Mechanisms of Rats Submitted to Prolonged Physical Exercise

This study aimed to determine the effects of diets chronically supplemented with branched-chain amino acids (BCAA) on the fatigue mechanisms of trained rats. Thirty-six adult Wistar rats were trained for six weeks. The training protocol consisted of bouts of swimming exercise (one hour a day, five times a week, for six weeks). The animals received a control diet (C) (n = 12), a diet supplemented with 3.57% BCAA (S1) (n = 12), or a diet supplemented with 4.76% BCAA (S2) (n = 12). On the last day of the training protocol, half the animals in each group were sacrificed after one hour of swimming (1H), and the other half after a swimming exhaustion test (EX). Swimming time until exhaustion was increased by 37% in group S1 and reduced by 43% in group S2 compared to group C. Results indicate that the S1 diet had a beneficial effect on performance by sparing glycogen in the soleus muscle (p < 0.05) and by inducing a lower concentration of plasma ammonia, whereas the S2 diet had a negative effect on performance due to hyperammonemia (p < 0.05). The hypothalamic concentration of serotonin was not significantly different between the 1H and EX conditions. In conclusion, chronic BCAA supplementation led to increased performance in rats subjected to a swimming test to exhaustion. However, this is a dose-dependent effect, since chronic ingestion of elevated quantities of BCAA led to a reduction in performance.Fundacao de Amparo a Pesquisa do Estado de Sao Paulo (FAPESP)Fundacao de Amparo a Pesquisa do Estado de Sao Paulo (FAPESP)Coordenacao de Aperfeicoamento de Pessoal de Nivel Superior (CAPES)Coordenacao de Aperfeicoamento de Pessoal de Nivel Superior (CAPES

Efeito da temporada de basquetebol profissional sobre o perfil lipídico

The aim of the present study was to verify the effect of the professional basketball season on the lipids profile. Seven professional players (age: 23.6±4.3 years; body mass: 110.2±17.5 kg; height: 195.4±10.3 cm) were evaluated before and after a period ranging 4 moths, during national professional basketball season (2 games per week, 2 to 3 tactical and technical exercise workout, 2 to 3 strength exercise workout, 1 to 2 recuperative workout and 1 day of passive rest, all of then as a median per week). Blood samples and anthropometric measures were taken. The first visit was made before the beginning of the season and the second visit two days (48 hours) after the ending of the last game of the season. The lipids profile (triglyceride, VLDL, LDL-cholesterol, HDL-cholesterol, and total cholesterol) was analyses by commercial kits (Labtest®, Brazil). The comparison between the results (before and after) was carried through by non-parametric Wilcoxon pair test. The level of significance of 5% was used (p < 0.05). After basketball season, a reduction in the LDL-cholesterol plasma concentrations was demonstrated (before: 111.40±9 mg/dL after: 84.60±8.50 mg/dL; p < 0.05), as well as in total cholesterol (before: 171.20±6.44 mg/dL after: 148.20±6.37 mg/dL; p < 0.05). Besides, increase in rate the HDL/total cholesterol was found (before: 0.22±0.03 after: 0.27±0.06; p < 0.05). The results herein found indicate that the basketball season may induce changes in LDL-cholesterol, total cholesterol and in rate the HDL/total cholesterol concentrations, suggesting a modulatory effect on the lipid profile in professional basketball player after 4 moths season.O objetivo do presente estudo foi verificar o efeito da temporada de basquetebol profissional sobre o perfil lipídico. Sete jogadores profissionais (idade: 23,6±4,3 anos; massa corporal: 110,2±17,5 kg; estatura: 195,4±10,3 cm) foram avaliados antes e após um período de 4 meses, relativos a uma temporada nacional de basquetebol profissional (2 partidas por semana, 2 a 3 sessões de treinos técnicos e tático, 2 a 3 sessões de treino de musculação, 1 a 2 sessões de treino regenerativo e 1 dia de descanso passivo, sendo todos a média por semana) . Os jogadores foram submetidos a analise antropométrica e coleta sangüínea. A primeira visita foi feita antes do início da temporada e a segunda visita dois dias (48 horas) após o término da última partida da temporada. Foram realizadas análises do perfil lipídico (triacilglicerol, VLDL, LDL-colesterol, HDL-colesterol, e colesterol total) por kits comerciais (Labtest®, Brasil). A comparação entre os resultados foi realizada pareadamente (antes e depois o início da temporada) por teste não paramétrico de Wilcoxon. Utilizou-se o nível de significância de 5% (p < 0,05). Após a temporada, foi demonstrada diminuição nas concentrações da LDL-colesterol (pré: 111,40±9 mg/dL vs pós: 84,60±8,50 mg/dL; p < 0,05), bem como do colesterol total (pré: 171,20±6,44 mg/dL vs pós: 148,20±6,37 mg/dL; p < 0,05). Além disso, foi encontrado aumento na taxa HDL/colesterol total (pré: 0,22±0,03 vs pós: 0,27±0,06; p < 0,05). Os resultados indicam que a temporada de basquetebol profissional pode induzir alterações na concentração de LDL-colesterol, de colesterol total e na taxa HDL/colesterol total, sugerindo um efeito modulador sobre o perfil lipídico de jogadores profissionais de basquetebol após uma temporada de 4 meses

Low and moderate, rather than high intensity strength exercise induces benefit regarding plasma lipid profile

<p>Abstract</p> <p>Background</p> <p>The effects of chronic aerobic exercise upon lipid profile has been previously demonstrated, but few studies showed this effect under resistance exercise conditions.</p> <p>Objective</p> <p>The aim of this study was to examine the effects of different resistance exercise loads on blood lipids.</p> <p>Methods</p> <p>Thirty healthy, untrained male volunteers were allocated randomly into four groups based at different percentages of one repetition maximum (1 RM); 50%-1 RM, 75%-1 RM, 90%-1 RM, and 110%-1 RM. The total volume (sets × reps × load) of the exercise was equalized. The lipid profile (Triglycerides [TG], HDL-cholesterol [HDL-c], LDL-cholesterol, and Total cholesterol) was determined at rest and after 1, 24, 48 and 72 h of resistance exercise.</p> <p>Results</p> <p>The 75%-1 RM group demonstrated greater TG reduction when compared to other groups (p < 0.05). Additionally, the 110%-1 RM group presented an increased TG concentration when compared to 50% and 75% groups (p = 0.01, p = 0.01, respectively). HDL-c concentration was significantly greater after resistance exercise in 50%-1 RM and 75%-1 RM when compared to 110%-1 RM group (p = 0.004 and p = 0.03, respectively). Accordingly, the 50%-1 RM group had greater HDL-c concentration than 110%-1 RM group after 48 h (p = 0.05) and 72 h (p = 0.004), respectively. Finally, The 50% group has showed lesser LDL-c concentration than 110% group after 24 h (p = 0.007). No significant difference was found in Total Cholesterol concentrations.</p> <p>Conclusion</p> <p>These results indicate that the acute resistance exercise may induce changes in lipid profile in a specific-intensity manner. Overall, low and moderate exercise intensities appear to be promoting more benefits on lipid profile than high intensity. Long term studies should confirm these findings.</p

Effect of bench press exercise intensity on muscle soreness and inflammatory mediators

This study compared four different intensities of a bench press exercise for muscle soreness, creatine kinase activity, interleukin (IL)-1, IL-6, tumor necrosis factor- (TNF-), and prostaglandin E2 (PGE2) concentrations in the blood. Thirty-five male Brazilian Army soldiers were randomly assigned to one of five groups: 50% one-repetition maximum (1-RM), 75% 1-RM, 90% 1-RM, 110% 1-RM, and a control group that did not perform the exercise. The total volume (setsrepetitionsload) of the exercise was matched among the exercise groups. Muscle soreness and plasma creatine kinase activity increased markedly (P0.05) after exercise, with no significant differences among the groups. Serum PGE2 concentration also increased markedly (P0.05) after exercise, with a significantly (P0.05) greater increase in the 110% 1-RM group compared with the other groups. A weak but significant (P0.05) correlation was found between peak muscle soreness and peak PGE2 concentration, but no significant correlation was evident between peak muscle soreness and peak creatine kinase activity, or peak creatine kinase activity and peak PGE2 concentration. All groups showed no changes in IL-1, IL-6 or TNF-. Our results suggest that the intensity of bench press exercise does not affect the magnitude of muscle soreness and blood markers of muscle damage and inflammation.FAPESP[06/54683-8

Alterações na produção de IL-10 e TNF-&#945; no músculo esquelético em ratos com insuficiência cardíaca secundária ao infarto do miocárdio Changes in the production of IL-10 and TNF-&#945; in skeletal muscle of rats with heart failure secondary to acute myocardial infarction

FUNDAMENTO: Estudos recentes demonstram que a expressão de mediadores inflamatórios, como as citocinas, é um importante fator de desenvolvimento e progressão da insuficiência cardíaca (IC), principalmente na presença de disfunção ventricular esquerda. Essas alterações têm sido demonstradas tanto no plasma como no músculo cardíaco e, mais recentemente, no músculo esquelético de ratos e pacientes com IC. OBJETIVO: Investigar a produção e expressão do fator de necrose tumoral-&#945; (TNF-&#945;) e interleucina-10 (IL-10) no músculo sóleo e extensor digital longo (EDL) em animais com disfunção ventricular pós-infarto do miocárdio (IM). MÉTODOS: Utilizaram-se ratos Wistar machos que foram submetidos à ligadura da artéria coronária esquerda sem posterior reperfusão. Quatro semanas após esse procedimento, os animais foram submetidos à análise ecocardiográfica e divididos nos seguintes grupos experimentais: falso operado (Sham) e IM. Mantiveram-se em observação por um período adicional de 8 semanas. RESULTADOS: O nível da citocina TNF-&#945; aumentou 26,5% (p < 0,05), e sua expressão gênica, 3 vezes (p < 0,01). O nível de IL-10 apresentou diminuição de 38,2% (p < 0,05). Ambas as alterações ocorreram apenas no músculo sóleo, sem alterações no EDL. A diminuição (36,5%, p < 0,05) na razão IL-10/ TNF-&#945; deveu-se tanto ao aumento dos níveis teciduais do TNF-&#945; quanto à diminuição da IL-10 dos níveis teciduais. CONCLUSÃO: Nossos resultados demonstraram alterações relevantes na razão IL-10/ TNF-&#945;, o que pode ter um papel aditivo na avaliação da deterioração e progressão do quadro da disfunção ventricular esquerda pós-IM. Além disso, nosso estudo sugere que essas alterações parecem estar relacionadas ao tipo de fibra muscular.<br>BACKGROUND: Recent studies show that the expression of inflammatory mediators, such as cytokines, is an important factor for the development and progression of heart failure (HF), especially in the presence of left ventricular dysfunction. These changes have been demonstrated both in the plasma and heart muscle and, more recently, in skeletal muscle of rats and in patients with HF. OBJECTIVE: To investigate the production and expression of tumor necrosis factor-&#945; (TNF) and interleukin-10 (IL-10) in the soleus and the extensor digitorum longus (EDL) muscles of animals with left ventricular dysfunction after myocardial infarction (MI). METHODS: We used male Wistar rats that underwent ligation of the left coronary artery without reperfusion. Four weeks after this procedure, the animals underwent echocardiography and were divided into the following experimental groups: sham operated (sham) and IM. They remained under observation for a further period of 8 weeks. RESULTS: The level of the cytokine TNF-&#945; increased by 26.5% (p <0.05), and its gene expression increased 3 times (p <0.01). The level of IL-10 decreased by 38.2% (p <0.05). Both changes occurred only in the soleus muscle, with no change in the EDL. The decrease (36.5%, p <0.05) in the IL-10/TNF-&#945; ratio was due to both increased tissue levels of TNF-&#945; and decreased tissue levels of IL-10. CONCLUSION: Our results showed significant changes in the IL-10/TNF-&#945; ratio, which may have an additive role in the assessment of deterioration and progression of left ventricular dysfunction post-MI. Furthermore, our study suggests that these changes seem to be related to the muscle fiber type. (Arq Bras Cardiol 2010; 94(3):293-300