Friday 1 June 2012

Sports Nutrition Series:Part 1

Hello everyone,
This is the first article of the sports nutrition series. So let’s have a little recap of the previously discussed information. We should all now have a general idea of what and how Carbohydrates (CHO), Lipids and Proteins(PRO) are used in the body and how all of them can aid in each other’s specific processes by donating substrates via chemical reactions. Great, so now let us look into how these three nutrients affect the athletes of today’s world. In the following series I will be discussing the application of the information given in the earlier articles.  The goals are to determine what the best nutritional outline is for a trampolinist because this is my main demographic. Anyone out there who does not fall into this category please leave me a message and I will tailor an article to your sport. Nutrition is simple, when you know the mechanics of the body, which can take a long time, then finding the nutrition best for you is as easy as connecting dots. So let’s beginJ
                First let us outline the requirements of the sport of trampoline to all who are not aware. Individual trampoline consists of three routines; compulsory, optional 1 and optional 2. The compulsory and optional 1 are added together to get a “preliminary score” . The top ten athletes with the highest preliminary scores are allowed to do a finals routine which is the optional 2. The compulsory routine is a finesse oriented demonstration of 10 skills while the optional are a difficulty oriented demonstration consisting of 10 skills as well. The compulsory routine is relatively easy, rating usually an 8-14 out of 20 on the RPE scale (Rate of Perceived Exhersion).  An optional routine consists of harder skills and requires therefore more energy and constitutes an RPE of 15-20 depending on the athlete. These values are not cited but are based on the RPE’s of the athletes I have seen, coached, and of course, myself. The competition schedule of a world cup is generally pretty straight forward. Let us say for example there are 50 competitors. They cannot all compete at one time back to back after ONE GENERAL WARM UP that lasts usually about 45 minutes. Some athletes will be waiting a few hours just to compete. This obviously will hinder performance. Instead the athletes are split into groups called “Flights” and there may be anywhere from 10 to 15 competitors in a flight. All of them get a general warm up of 45 minutes, stand around for about 15 minutes before march in and then compete. Once announced to the crowd each participant will get a “One Touch” where they can take 30 seconds to re-warm up a specific part of a routine to help increase mental stability for the upcoming competition.  The competition time can take anywhere from 30 minutes per flight to an hour per flight usually. This depends on how easy the routines are to judge, length of routines, any injuries that occur and of course the number of athletes. Let us say in our example that there are 12 competitors and all of them make all of their routines (which is very unlikely). If we add up the time prolapsed in this best case scenario we will get a warm up to final routine time of 1 hour and 54 minutes. This assumes each athlete takes 1.5 minutes for every routine with no stops in the competition. ( 12 athletes x 1.5 minutes x3 routines/60 ( to convert into minutes) + 45 minute warm up + 15 minute march in= roughly 2 hours. So for the sake of this article we will assume that the nutritional demands of trampoline fit a two hour exercise period of interval exercise.
                CHO  is a glucose, fructose or galactose base that can be added together or mixed to create different forms of CHO. CHO have been shown to be essential for performance of athletes across the world and have had many studies performed on their use in sports. The general consensus is that increasing CHO before, during and after exercise will improve performance.  Unfortunately it is not as easy as loading up on pasta before a competition due to several factors. The first one that I mentioned in the last article about protein was that there is a limit to how much CHO can be used by the body. This seems to be about 1gram per minute. I may have said 1 gram/HOUR last article and I apologize for the typo. It has been shown that if 70% of daily energy intake is from CHO rather than the normal recommended value of 50-60%, there will be an increase in performance.  Extra CHO before a competition helps in a few ways which include (1) increases glycogen stores,(2) increase blood glucose levels. Increasing glycogen stores will obviously allow a larger base for all energy that is about to be used during the competition. Increasing blood glucose levels will allow the glycogen to be spared which saves the body from having to waste energy by breaking down glycogen into glucose to be put into glycolysis. Roughly 1600kcal of CHO is stored in the muscles and only about 400kcal is stored in the Liver. The liver does not want these kcals to be used because they are a last resort.  When one study injected CHO into the blood during exercise only about 25% of muscle glycogen was used which shows how much glycogen was saved.  Not all studies show this but it may be better to do it anyway and not get results then to not do it and lose energy at a quicker rate.  Well all studies show different amounts but the general consensus is that a minimum of 22 grams/hour are required to achieve a benefit. 16g/hour has been shown however in a single study to still yield results. It has been reported that about 60-70grams/hour is the maximum amount that has shown increases in performance.  Well if the max amount used by the body is 1 gram/hour then how can we get anything over 60 grams? It all depends on what CHO is digested.  Once in the body the amount of CHO used for energy depends on the absorption rate of the type of CHO. The CHO is absorbed in the small intestine into the blood and is circulated from there to different parts of the body.  CHO is separated into 2 categories; simple and complex. Simple sugars are the 3 bases that i mentioned by themselves not linked. A complex CHO is a chain of CHO monomers. For a normal, non athletic person, complex sugars are better due to the fact they are already in the form that they are going to be stored in ie. long chains of glycogen. However, for our populations simple sugars may be better due to the fact that we want them to circulate in the blood in singles rather than needing to be broken down once in the muscle. Like mentioned above it makes the energy easier to use.  (This is my own thought and I have not read any material backing this up). Galactose and fructose are not ideal for maximum energy output due to the fact they have to be converted into glucose once inside the body. Fructose and galactose can be used at about o.6grams/minute rather than the 1.0 grams/ minute of glucose.  Fructose is transported by Glucose Transporter 5 (GLUT5). Glucose and Galactose, our other two base CHO, are transported into the blood by Sodium Dependant Glucose Transporter 1(SGLT1). This difference of transporters may cause less of a competition for transport in the body which actually yields to an absorption rate of 1.2g/min-1.7g/min. This basically means that if you take a bit of fructose and glucose when CHO loading then you will get a 20-50% increase in the amount of CHO that can be used by the body for the competition rather than just using fructose or glucose individually. The only problem it seems with fructose is that it only increases liver glycogen stores and not muscle glycogen stores. Obviously this may be an issue to athletes who need the glycogen if it is in the liver and harder to obtain rather than in the muscle. This is one of the reasons why fructose is not the best for CHO loading. Another reason is that fructose may be unabsorbed in the small intestine because it also competes with glucose and galactose for the GLUT2 transporter. This may cause the fructose to move into the large intestine where it may cause intestinal distress.  It is shown that the digestion, absorption and circulation of CHO play a large part in the usable CHO for the body compared to the uptake from the blood and use by the muscle. 
                What about duration of the activity. Does that matter? Yes it does, greatly. It has been shown that exercise lasting over an hour is the only type that is benefitted by increasing CHO intake before or during. Many studies have shown that generally any exercise that is reaching 85% of a V02 Max does not have high absorption rates compared to exercise around 70% of V02 max. 70% is about where a semi experienced long distance runner can maintain their energy output without getting fatigued. This is called a lactic threshold. It is the energy output that can be achieved before lactic acid is created. If the body is using too much energy glycolysis converts pyruvate into lactic acid to create energy. Some lactic thresholds have been reported to be around 80% of V02 max. This is where we may get into some problems for trampolinists and CHO loading. From the competitions I see the average trampolinist is doing very short burst of energy, nowhere near an hour. In total we may be at competition for 2 hours but only actually doing exercise for a total of roughly 18 minutes. (15 warm up turns x 1 minute each + 1 minute for each routine).  It can be argued however that a larger CHO store before competition will allow better recovery between turns and routines but one problem still remains. We only use glucose to fuel about 2/3 of our routine. The energy for the pre-bounces is mostly coming from the phosphogen system also known as creatine system, which was mentioned in the last article. Creatine is made from amino acids, not glucose. Glucose takes over after our first skill and allows us to maintain our height and flipping momentum but is not used to maintain a long period of exercise. By the time our routines are done we have not used much glucose and have plenty of time to naturally replenish the CHO stores to certain degrees before our next routine. CHO may be ingested after a routine to increase the amount of glucose in the blood for easier energy production but storing the CHO does not seem to matter at all for a trampolinist. Afterwards the trampolinist will want to increase CHO stores to allow the body to not have to use proteins to replenish CHO stores. As discussed earlier this will break down too many amino acids and cause a negative nitrogen balance. What energy system a trampolinist uses is actually a question that I do not really know. I do not think anyone really does know considering not many studies have been done on a trampolinist. I have been told that a few actually have been done and I am trying to get my hands on them. I am working with CSC currently to perform a few studies to try and figure out exactly what energy pathways are used by a trampolinist. Understanding these pathways will be a key factor into determining the nutrition of the athletes. For now I am basing all my data on personal experience and my research abilities.
                So the conclusion seems to be that CHO loading may not yield much of an improvement in trampolinists due to the fact that it is primarily use for long endurance sports. CHO may increase recovery between turns and routines however but this has not been proven, yet. Replenishing CHO stores after a workout will allow the nitrogen balance to remain neutral or positive which is needed for improvements in muscle building which will obviously allow a trampolinist to jump higher and perform harder skills that require more muscle force. Only one question remains. What will give me enough CHO for potential improvement? As mentioned earlier you need probably at least 22grams/hour. Well a “musketeer” chocolate bar contains 46 grams of CHO- most of them probably simple sugars.  Now if you are a fan of complex sugars then you want pasta and a full plate of pasta will give you the required amount of CHO to increase the stores and amount in the blood for increased performance. For a trampolinist, he or she may want to stick to the chocolate bar for a quick boost. This may pose a problem however due to a sugar crash. This is when the blood glucose levels increase rapidly due to increase of a rich CHO meal and then decrease due to insulin taking the glucose and putting it into the cell. This may be counteracted by small amounts of CHO being ingested at regular intervals such as every 5 minutes. Every turn take a small piece of a Hershey’s. This will keep the blood glucose levels roughly balanced throughout the competition.   This may or may not help avoid a sugar crash.  It has been suggested that drinking cold water or tea during CHO ingestion may help prevent a sugar crash as well.
 I will continue this series by talking about lipid ingestion for athletes next time. All of the stats I have given are NOT my own unless stated otherwise and should not be viewed as such. I have the references on my computer and if need be I can show my sources. I have not for the purpose of being lazy. If you want references please let me know. 
ThanksJ

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