We have already talked about the production of protein (see articles: The needs protein, protein 1st part, 2nd part and and 3rd part), now we see deepen the theme of branched amino acids. We have seen how essential amino acids are those that our body can not synthesize itself and therefore must necessarily be made through proper nutrition, these are: threonine, valine, leucine, isoleucine, methionine, phenylalanine, tryptophan, lysine, histidine and arginine (the latter two essential for the body growth). Amino acids essential substitutes: cysteine, cystine and tyrosine. Amino acids not essential: glycine, alanine, nor-leucine, aspartic acid, acid glutamine, proline, ossiprolina, arginine, serine, histidine. The essential amino acids are occurring in eggs, meat, fish and cheese. Usually a diet well-structured and varied allows down to recruit a sufficient quantity of essential amino acids, so that in the western world there are food shortages in this direction, which persists in undernourished areas of the planet. Several studies have repeatedly shown the usefulness and importance of amino acids essential in sports performance, but not all studies have resulted in an unique position. In particular, differences on the conclusions have the same amino acids branched into sports performance, their need for integration and how to recruitment. This is certainly partly due to the fact that not always the studies were conducted on athletes who practiced the same sport and then varied the systems used energy. Moreover, it must also consider the specificity of each individual sport and especially the capabilities that this leaves down to eat properly during the same athletic gesture. Now some research would emphasized as the particular prolonged muscular activity, is characterized by reduced protein synthesis due to the lack of amino acids that occurs in response to their use as an energy source. This reduction would occur during the recovery phase. According to these studies, and integration of amino acids, both before and during and immediately after the athletics would be advisable to bring a sensitive and increases performance. These studies, however, were conducted on runners, sport long associated with a poor capacity to reinstate the athlete energy consumed during the same competition. We can not be adapted to cycling this study for obvious reasons. Indeed, the cyclist has broad authority to reinstate the energy expenditure during the race both liquid and solid supplements, if taken with the right arrangements allow down to maintain stocks of high carbohydrate (and lipid) required for the synthesis of energy. We must not forget that the protein, and thus the amino acids, become a source of energy unless there is a shortage of carbohydrates and fats, or whether their absorption exceeds the demands of protein synthesis being converted into fatty acids and carbohydrates and stored in the form of glycogen or triglycerides. Now it seems clear that an intake of branched amino acids before the competition is unnecessary, it would be used by the eventual improvement in stocks of glycogen, low-energy system used in cycling road and that can be possibly better integrated with intake of carbohydrates. Other studies also have shown how even in body building, where there is the cult of hyperproteic diet, a massive recruitment of amino acids not lead to sensitive increases muscle mass compared to athletes who had a more balanced assumption. The study, in particular, has highlighted the growth of muscles and performance is not only linked to the recruitment of proteins, namely the muscle to grow it needs proteins, but especially of training. To this point, having reached the proper intake of proteins under its load of training, an additional increase of share protein does not improve performance and speed of growth of muscle mass. This same study had also shown, in comparison, as some sport of resistance, always the runners, requiring a greater intake of protein because the same were used for the synthesis of energy, given the impossibility of these athletes to eat properly during the performance sport. What that does not happen when the athlete has the opportunity to eat properly. Other studies also have shown that it is not true the idea that a massive introduction of amino acids can stimulate the production of testosterone and thus contribute to further improvement of sports performance. It is true that some research has shown that an intake of branched amino acids essential to a stimulus leads to production of testosterone, but this has been shown only on residents of long and precarious health conditions in which the recruitment of amino acids branched managed to restore some balance psychophysical, but always in comparison to the previous precarious state of health. Then in healthy subjects and particularly in sports has never been and show the possibility that an intake of amino acids leading to an increased production of testosterone. In light of the facts, then, seems to exclude the motion safer, which in cycling recruitment of a branched amino acid before and during athletic performance, is cheap and leads to improved athletic performance. There remains the issue of appointment after the athletics. The proteins have the primary task of construction and reconstruction of muscle fibers, an intake of branched amino acids after the athletics could then lead to real benefits to that effect. But immediately the end of a high effort by the agency priority to the reconstruction of the energy stocks, and a recruitment of branched amino acids immediately after the sport would not be used for the reconstruction of muscle tissue, but for rebuilding stocks of glycogen, which can be better done with the recruitment of carbohydrates. So that intake of amino acids is preferable after the athletics, but at a distance of the end of it and after proper reintegration of carbohydrates. So it is preferable to their recruitment distance of about two and a half hours after the end of the race. Regarding the quantity to be taken that will be calculated taking into account the daily calories needs and the breakdown of calories and principles in food meals. As mentioned in an athlete with an average age of about 20-22 years can take a value of 1,6-1,8 grams of protein per kilogram of body weight per day, while above this value in young people between the 15-20 years, if the optimal dose is about 1,8-2,0 grams of protein per kilogram of body weight per day. We have, then, to 2,5-3 grams of protein per day per kilogram of body weight in even younger players, but already engaged in sporting activities. The value protein taken daily should be approximately 12-14% of daily caloric needs, with a percentage of protein of animal origin, constituting about 60% of total protein, with an equitable distribution of the eight amino acids essential. We said that a well structured diet will lead to achieving those values naturally without the need for supplements, but if it becomes necessary recruitment then this should be so wise. In particular, we should not exceed the value of total protein in order to avoid an increase of nitrogen in the blood uncoagulable overload and subsequent kidney to eliminate it. It will give priority to the three essential amino acids: leucine, isoleucine, valine, which alone make up about 60% of human skeletal muscle. The composition of the optimal ratio is 2:1:1; 2 shares of leucine, 1 part of an isoleucine and valine. Is preferable, then, associate with this integration also that of vitamins B1 and B6 that will facilitate the assimilation. If taken so wise as indicated above, there should be not collateral effects.