Revista Brasileira de Nutrição Esportiva

195-203

Authors: Luiz Henrique Carrilho

Introduction: Good nutrition back better development for physical performance, there may be a decrease in muscle fatigue, and also preventing the loss of lean mass, but due to the difficulties of lack of time people nowadays can maintain a diet balanced, grows ever more interest in dietary supplements that promise the same benefits of proper nutrition. The whey protein (WP) is a protein supplement made from whey, which is widely used due to their beneficial health properties in general. Objective: To demonstrate with this work, the relationship between the use of whey protein among practitioners or no physical activity. Materials and Methods: Systematic Literature Review. Results: there were 11 international articles on humans and 2 national addressing the whey protein with exercise performance or not. Discussion: were found different training protocols and diet. Results were decreased weight, reduced body fat, increased satiety, easy digestibility, increased bone mineral density, lean mass, muscle and liver glycogen and strength. Conclusion: in general, the consumption of whey protein promoted improvement in both health and in performance, but nothing can replace a balanced diet and suitable for every lifestyle. Key words: Whey protein, Benefits, Food supplement, Physical activity.

212-223

Authors: Luciana Aparecida Gonçalves

The branched chain amino acids (AACR/BCAA): leucine, isoleucine and valine are essential amino acids in the human diet. Lately these amino acids have gaining some attention due their physiological properties, especially leucine. The objective of this literature review is to aim for the highest number of studies and other reviews with humans, approaching the effects of leucine supplementation singly or not in anabolic processes of synthesis, muscle protein degradation and prevention of sarcopenia. Eight studies were evaluated, all of them with humans, with or without physical activity and with or without food. Among the studies reviewed, it was found that 7 studies associate the beneficial effects of leucine supplementation and only one mentions the endurance exercises had no beneficial results with the use of leucine with respect to the muscle synthesis associated with exercise. Some studies report that leucine promotes muscle protein synthesis by protein kinase mammalian target of rapamycin (mTOR) that stimulates the three key proteins: 70 kDa ribosomal protein S6 kinase (p70S6K), eukaryotic translation initiation factor 4E binding protein 1 (4E-BP1), and eukaryotic initiation factor 4G (elF4G). It also verifies that leucine acts by stimulating the translation initiation stage of messenger RNA into protein by mechanisms dependent and independent of insulin and mTOR. Although 90% of the articles have a positive standpoint regarding leucine supplementation and muscle protein synthesis further studies and research that addresses more training are needed especially endurance. Key words: BCAA, Leucine, Protein Synthesis, Supplementation, Insulin.

233-245

Authors: Milena Biazi Prado Pereira

Introduction: Physical exercise has many benefits, however, it may increase the production of free radicals or reactive oxygen species (ROS) in the muscle and other tissues which may contribute to tissue and cellular damage and may impair physical performance. The antioxidant defense system is extremely important to protect against oxidative stress. Objective: Discuss the role of antioxidants against oxidative stress observed in weightlifting physical exercise. Literature Review: Selected studies from 1998 to 2012, totaling 50 articles (26 international and 24 national). The reviewed literature has show that there are studies with positive and negative results regarding antioxidant supplementation on oxidative stress induced by exercise, so definitive conclusions are complicated by variations in population, the timing, antioxidants dosage variations and different protocols, which induce different degrees of muscle damage. Conclusion: Oxidative stress can be observed in different types of exercise, including weightlifting, however, systematic training induce positive adaptations in the antioxidant defense in response to increased production of ROS. Furthermore, antioxidant supplementation should only be indicated in case of deficit and for high performance athletes, because studies are still inconclusive regarding the benefits against oxidative stress and therefore its recommendation for the general population. Key words: Antioxidants, Oxidative Stress, Weightlifting, Free Radicals.