An Experimental Model for Resistance Exercise in Rodents

This study aimed to develop an equipment and system of resistance exercise (RE), based on squat-type exercise for rodents, with control of training variables. We developed an operant conditioning system composed of sound, light and feeding devices that allowed optimized RE performance by the animal. With this system, it is not necessary to impose fasting or electric shock for the animal to perform the task proposed (muscle contraction). Furthermore, it is possible to perform muscle function tests in vivo within the context of the exercise proposed and control variables such as intensity, volume (sets and repetitions), and exercise session length, rest interval between sets and repetitions, and concentric strength. Based on the experiments conducted, we demonstrated that the model proposed is able to perform more specific control of other RE variables, especially rest interval between sets and repetitions, and encourages the animal to exercise through short-term energy restriction and “disturbing” stimulus that do not promote alterations in body weight. Therefore, despite experimental limitations, we believe that this RE apparatus is closer to the physiological context observed in humans

An Experimental Model for Resistance Exercise in Rodents

This study aimed to develop an equipment and system of resistance exercise (RE), based on squat-type exercise for rodents, with control of training variables. We developed an operant conditioning system composed of sound, light and feeding devices that allowed optimized RE performance by the animal. With this system, it is not necessary to impose fasting or electric shock for the animal to perform the task proposed (muscle contraction). Furthermore, it is possible to perform muscle function tests in vivo within the context of the exercise proposed and control variables such as intensity, volume (sets and repetitions), and exercise session length, rest interval between sets and repetitions, and concentric strength. Based on the experiments conducted, we demonstrated that the model proposed is able to perform more specific control of other RE variables, especially rest interval between sets and repetitions, and encourages the animal to exercise through short-term energy restriction and “disturbing” stimulus that do not promote alterations in body weight. Therefore, despite experimental limitations, we believe that this RE apparatus is closer to the physiological context observed in humans

Leucine supplementation combined with resistance exercise improves the plasma lipid profile of dexamethasone-treated rats

The impact of leucine supplementation and resistance exercise (RE) on plasma lipid profile was evaluated in adult rats treated with dexamethasone, an experimental model of dyslipidemia. Total cholesterol did not differ among groups. Furthermore, leucine supplementation did not promote improvement in the plasma total cholesterol and LDL-c of the animals. However, plasma TG and VLDL-c were significantly decreased and HDL-c increased after 7 days of leucine supplementation combined with RE. In conclusion, leucine supplementation combined with RE, but not isolated, improved the plasma lipid profile of dexamethasone-induced dyslipidemic rats

The need of a weight management control program in judo: a proposal based on the successful case of wrestling

Judo competitions are divided into weight classes. However, most athletes reduce their body weight in a few days before competition in order to obtain a competitive advantage over lighter opponents. To achieve fast weight reduction, athletes use a number of aggressive nutritional strategies so many of them place themselves at a high health-injury risk. In collegiate wrestling, a similar problem has been observed and three wrestlers died in 1997 due to rapid weight loss regimes. After these deaths, the National Collegiate Athletic Association had implemented a successful weight management program which was proven to improve weight management behavior. No similar program has ever been discussed by judo federations even though judo competitors present a comparable inappropriate pattern of weight control. In view of this, the basis for a weight control program is provided in this manuscript, as follows: competition should begin within 1 hour after weigh-in, at the latest; each athlete is allowed to be weighed-in only once; rapid weight loss as well as artificial rehydration (i.e., saline infusion) methods are prohibited during the entire competition day; athletes should pass the hydration test to get their weigh-in validated; an individual minimum competitive weight (male athletes competing at no less than 7% and females at no less than 12% of body fat) should be determined at the beginning of each season; athletes are not allowed to compete in any weight class that requires weight reductions greater than 1.5% of body weight per week. In parallel, educational programs should aim at increasing the athletes', coaches' and parents' awareness about the risks of aggressive nutritional strategies as well as healthier ways to properly manage body weight.The authors would like to thank FAPESP (#06/51293-4 and #09/02896-6) and CNPq (#1428 10/2009-6) for the financial support.The authors would like to thank FAPESP (#06/512934 and #09/028966) and CNPq (#1428 10/20096) for the financial support

Effects of leucine supplementation and resistance exercise on dexamethasone-induced muscle atrophy and insulin resistance in rats

Objective: We aimed to evaluate the effects of resistance exercise (RE) and leucine (LEU) supplementation on dexamethasone (DEXA)-induced muscle atrophy and insulin resistance.Methods: Male Wistar rats were randomly divided into DEXA(DEX), DEXA + RE (DEX-RE), DEXA + LEU (DEX-LEU), and DEXA + RE + LEU (DEX-RE-LEU) groups. Each group received DEXA 5 mg . kg(-1) . d(-1) for 7 d from drinking water and were pair-fed to the DEX group; LEU-supplemented groups received 0.135 g . kg(-1) . d(-1) through gavage for 7 d; the RE protocol was based on three sessions of squat-type exercise composed by three sets of 10 repetitions at 70% of maximal voluntary strength capacity.Results: the plantaris mass was significantly greater in both trained groups compared with the non-trained groups. Muscle cross-sectional area and fiber areas did not differ between groups. Both trained groups displayed significant increases in the number of intermediated fibers (IIa/IIx), a decreased number of fast-twitch fibers (IIb), an increased ratio of the proteins phospho(Ser2448)/ total mammalian target of rapamycin and phospho(Thr389)/total 70-kDa ribosomal protein S6 kinase. and a decreased ratio of phospho(Ser253)/total Forkhead box protein-3a. Plasma glucose was significantly increased in the DEX-LEU group compared with the DEX group and RE significantly decreased hyperglycemia. the DEX-LEU group displayed decreased glucose transporter-4 translocation compared with the DEX group and RE restored this response. LEU supplementation worsened insulin sensitivity and did not attenuate muscle wasting in rats treated with DEXA. Conversely, RE modulated glucose homeostasis and fiber type transition in the plantaris muscle.Conclusion: Resistance exercise but not LEU supplementation promoted fiber type transition and improved glucose homeostasis in DEXA-treated rats. (C) 2012 Elsevier Inc. All rights reserved.Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Univ São Paulo, Lab Appl Nutr & Metab, Sch Phys Educ & Sports, São Paulo, BrazilUniv São Paulo, Inst Biomed Sci, São Paulo, BrazilUniv São Paulo, Lab Mol & Cellular Physiol Exercise, Sch Phys Educ & Sports, São Paulo, BrazilUniv São Paulo, Sch Med, Lab Expt Hypertens, São Paulo, BrazilUniversidade Federal de São Paulo, Dept Biosci, São Paulo, BrazilClermont Univ, UFR Med, UMR Nutr Humaine 1019, Clermont Ferrand, FranceINRA, UMR Unite Nutr Humaine 1019, F-63122 St Genes Champanelle, FranceUniversidade Federal de São Paulo, Dept Biosci, São Paulo, BrazilFAPESP: 08/51090-1FAPESP: 10/07062-3FAPESP: 10/10852-6FAPESP: 11/04690-6Web of Scienc

Low-Intensity Swimming Training does not Improve Hypertension in Rats

Abstract Aim: To investigate the effects of low-intensity swimming training upon arterial blood pressure in 26-weeks-old male spontaneously hypertensive rats. Methods: The animals were randomly divided into two groups: sedentary (SED, n = 7) and trained (TR, n = 7). The aerobic training consisted of 90-min swimming sessions, five days a week. After nine weeks of intervention, the arterial blood pressure and heart rate were invasively measured using a catheter inserted into the femoral artery. Conclusion: The present study demonstrated that low-intensity swimming training cannot improve arterial blood pressure in an experimental model of severe hypertension

Surfe profissional brasileiro: existe correlação entre atividades desenvolvidas e ranking?

ResumoIntrodução: No contexto atual, pouco se sabe sobre as atividades que caracterizam o treinamento desenvolvido pelos surfistas profissionais brasileiros, inferindo assim a interferência do mesmo na melhora do rendimento físico e técnico destes atletas. Objetivo: O objetivo do presente estudo foi de explorar as atividades desenvolvidas pelos surfistas profissionais e correlacionar com a posição no ranking nacional. Métodos: Para tanto, participaram da amostra 14 atletas. Realizou-se uma pesquisa do tipo survey que utilizou como instrumento, para coleta de dados, um questionário com nove questões relacionando as características dos sujeitos analisados e as atividades desenvolvidas na busca de melhorar o desempenho esportivo. Foi realizado o teste de correlação de Spearman entre o número de atividades que cada sujeito desenvolvia e sua posição no ranking. Resultados: Os resultados indicaram que o treinamento físico constitui-se, majoritariamente, pelas seguintes atividades: alongamento, corrida, filmagem, musculação, bicicleta, ioga, prática mental, natação, treino de bateria e boxe. Não foi encontrada nenhuma correlação entre o número de atividades desenvolvidas e posição no ranking nacional. Conclusão: Conclui-se não existe correlação entre a posição no ranking nacional e o número de atividades desenvolvidas pelos atletas.         Palavras-chave: Surfe. Rendimento esportivo. Treinamento

Does Branched-Chain Amino Acids Supplementation Modulate Skeletal Muscle Remodeling through Inflammation Modulation? Possible Mechanisms of Action

Skeletal muscle protein turnover is modulated by intracellular signaling pathways involved in protein synthesis, degradation, and inflammation. The proinflammatory status of muscle cells, observed in pathological conditions such as cancer, aging, and sepsis, can directly modulate protein translation initiation and muscle proteolysis, contributing to negative protein turnover. In this context, branched-chain amino acids (BCAAs), especially leucine, have been described as a strong nutritional stimulus able to enhance protein translation initiation and attenuate proteolysis. Furthermore, under inflammatory conditions, BCAA can be transaminated to glutamate in order to increase glutamine synthesis, which is a substrate highly consumed by inflammatory cells such as macrophages. The present paper describes the role of inflammation on muscle remodeling and the possible metabolic and cellular effects of BCAA supplementation in the modulation of inflammatory status of skeletal muscle and the consequences on protein synthesis and degradation

Potential therapeutic effects of branched-chain amino acids supplementation on resistance exercise-based muscle damage in humans

Branched-chain amino acids (BCAA) supplementation has been considered an interesting nutritional strategy to improve skeletal muscle protein turnover in several conditions. In this context, there is evidence that resistance exercise (RE)-derived biochemical markers of muscle soreness (creatine kinase (CK), aldolase, myoglobin), soreness, and functional strength may be modulated by BCAA supplementation in order to favor of muscle adaptation. However, few studies have investigated such effects in well-controlled conditions in humans. Therefore, the aim of this short report is to describe the potential therapeutic effects of BCAA supplementation on RE-based muscle damage in humans. The main point is that BCAA supplementation may decrease some biochemical markers related with muscle soreness but this does not necessarily reflect on muscle functionality