Overview Programs designed to improve performance must be supported by solid nutritional practices. This involves many factors such as what to eat and drink, being aware of the most appropriate time for food intake and having recovery strategies in place to recoup expended energy. The specific roles of carbohydrates and hydration are important considerations for optimal physical performance. Foods are the life source of energy supply. Different foods have differing amounts of energy. Carbohydrates supplies 16kJ/gm, protein supplies 17kJ/gm and fat supplies 37kJ/gm. Therefore the type of food consumed prior to competition directly affects the quantity of energy available.
Overview cont. Fluid is also important as it is the bodys medium for cooling heated muscles and ultimately preventing dehydration. It assists in temperature regulation by transporting heat to the outside of the body, prevents damage to organs by diluting toxic waste, ids oxygen transportation to cells, assists the transportation of wastes from the body and helps eliminate carbon dioxide via the blood plasma. Thus a deficiency in food and fluid supply can place the health of an athlete at risk.
Nutritional Considerations: Pre-Performance Recommendations for pre-performance nutrition and hydration include: - Avoid foods that take a long period of time to digest such as foods high in fats, protein and fibre. Athletes are advised to eat meals high in complex carbohydrates (pasta, breads, cereals, fruits) because these provide slow energy release. - To avoid discomfort the appropriate amount of food to consume relates to the type of competition. Sustained, endurance type competitions (triathlons) require more kilojoules to fuel their metabolism than those in less demanding events.
Nutritional Considerations: Pre-Performance cont. - It is advised that a normal meal should be consumed three to four hours prior to competition. Small snacks and liquid preparations consumed within two hours of the competition with only carbohydrate solution drinks advisable in the last 30 minutes prior to competition.
Nutritional Considerations: Pre-Performance cont. - Adequate fluid intake should be consumed in the preceding days, particularly for endurance events. A side effect of this can be weight gain, particularly if carbohydrate intake has also increased ( each gram of glycogen stores 2.6 grams of water with it). - As a general rule, mL of fluid should be consumed in the two to three hour period prior to endurance performance and a further mL in the last quarter hour period.
Nutritional Considerations: Pre-Performance cont. Carbohydrate Loading: Is the technique of loading the muscles with glycogen in preparation for a high intensity endurance activity of more than 90 minutes. Average muscle glycogen levels are approximately mmol/Kg, but can increase by up to one-third in response to carbohydrate loading. In the past it has been viewed that the correct process of carbohydrate loading is to deplete glycogen stores in the body through intense training followed by a loading stage of rest and the consumption of large quantities of carbohydrates. However, new research suggests that a normal diet supplies sufficient amounts of carbohydrate to fuel athletes (7-12 grams of carbohydrate per kilo of body mass). People who need to carbohydrate load will already be involved in training schedules that regularly utilise stored glycogen, so the bodys ability to store fuel will be greater than that of non-athletes.
Nutritional Considerations: Pre-Performance cont. The process of carbohydrate loading should now be completed by maintaining a normal diet rich in carbohydrates and ensuring that athletes have a taper phase leading up to major competition. The taper phase is essential as it allows an athletes body to rest and reduce the utilisation of glycogen for energy whilst the consumption of carbohydrates through a normal diet boosts storage levels of glycogen in the liver and muscles. Carbohydrate loading has the benefit of delaying the point at which the muscles being repeatedly used run out of fuel.
Nutritional Considerations: During Performance Endurance events in hot and humid conditions can have a significant impact on the bodys fuel and fluid supplies. The need for carbohydrate and electrolyte replacement depends on a number of factors including intensity, duration, humidity, clothing type and individual sweat rates. The aim during performance is to conserve muscle glycogen and maintain blood glucose levels.
Nutritional Considerations: During Performance The following are nutritional considerations during performance: - Carbohydrate supplementation is only needed for exercise intensities 75% and above for prolonged periods of time (in excess of an hour). - Glycogen supplementation is not needed for low intensity, short duration exercise. - Adequate hydration by regular fluid intake must be maintained. It is suggested that mL of fluid, preferably in the form of a sports drink, be taken every minutes during exercise. An athlete should not wait until thirst develops before replenishing lost fluid.
Nutritional Considerations: During Performance The following are also considerations regarding hydration and performance during exercise: - Hydrate before and after physical activity. - Drink every minutes while running. Runners lose between three and five cups each hour. - Drink water or low-carbohydrate concentration sports drinks. Cool plain water or sports drinks that have less than 8% carbohydrate content is best. Anything above 8% slows the bodys absorption rate. - Ensure that you have trained properly and acclimatised to race conditions. - Wear clothing that breathes. - Avoid activities in times of high temperature and high humidity. - Avoid excess fat, salt and alcohol which act as diuretics. - Do not run if suffering a fever. - Learn to recognise the symptoms of heat stress.
Nutritional Considerations: Post-Performance A post performance nutrition plan aims to return the body to its pre-event state as quickly as possible, enabling full training to resume in preparation for the next phase of competition. The following recommendations should be considered: - Following endurance activity carbohydrate intake of grams in the first two hours is highly beneficial. This intake is then followed by intakes of grams every two hours until a total of grams of carbohydrate have been consumed. - Consume foods and drinks that are high in carbohydrate content and have a high Glycemic Index as apposed to a low one. (Glycemic index is a ranking system for carbohydrates based on how they affect blood sugar). High glycemic index carbohydrates increase blood glucose levels at a faster rate than low glycemic index carbohydrates. - Rehydrate your body, up to 150% of your normal intake levels. - Incorporate active rest after exercise as it assists with the manufacturing of red blood cells and new proteins.
Supplementation Dietary supplementation is found in many forms, including vitamins, minerals, protein, caffeine and creatine products. Why Supplement????? Supplement intake is routine for many competitors because it is believed to improve athletic performance. However, while perhaps supplying a psychological boost, supplements may be of little value if the diet is already well balanced in terms of nutritional requirements.
Supplementation Vitamins and Minerals Vitamins: Are inorganic compounds that are essential to maintaining bodily functions. They are required in very small quantities. They do not contain energy but act as catalysts that help the body use energy nutrients. They also assist with metabolic regulation and tissue building. The body is unable to manufacture vitamins, so diet must supply them. Some athletes take vitamins even though their normal diet contains all the necessary vitamins. The unnecessary intake of vitamins through supplementation is not only expensive but also potentially dangerous. Can lead to body aches, nausea, headaches and fatigue. Research shows that super-supplementation does not improve performance and that supplementation should not be a response to a desire for improved performance. Supplementation of vitamins should only be used to address health related matters such as vitamin deficiencies.
Supplementation Vitamins and Minerals Minerals: Are inorganic substances found in the body that are necessary for it to function adequately. They do not provide energy. Iron and calcium are most commonly deficient in athletes and inadequate supplies will affect performance. Iron is important as it is found in haemoglobin in red blood cells and assist with the transportation of oxygen and carbon dioxide around the body. Lack of iron is known as the deficiency sports anaemia and reduces performance. Characterised by a lack of energy and general fatigue. People most at risk include endurance athletes, females, vegetarians and adolescent males. Athletes should look to dietary sources rather than supplementation to prevent this condition i.e. Lean meats, particularly red and dark green leafy vegetables such as spinach and lettuce. Calcium deficiency is more specific to health. It is vital for strong bone structure and regular intake prevents the onset on osteoporosis (brittle bones) which can be developed later in life (particularly females). Adequate calcium intake through dairy products during childhood and adolescents has a positive effect on bone quality during later life. Athletes should look to dietary sources rather than supplementation to prevent this condition i.e. Milk, yoghurt and cheeses, leafy green vegetables and fish.
Supplementation Protein Protein supplements have been used widely by weight lifters, body builders and strength athletes for a long time. These supplements may be natural or synthetic and available in powder, fluid or solid formulations. The belief associated with protein is that a higher intake will positively affect muscle size. However, research suggests the idea that most athletes do not need or benefit from protein supplementation. This is because the majority of the population, including athletes, are getting on average more than the daily requirements through a normal balanced diet. Surveys reveal that most athletes consume well in excess of g/Kg body mass per a day (thats the equivolent of 23 extra eggs a day for a 70kg person), making supplementation both needless and wasteful. Additionally many protein supplements have many additives that pose health problems and may increase the risk of cancer. Furthermore, excess protein can increase the amount of calcium excreted in the urine and possible contribute to osteoporosis. Unlike excess carbohydrates which can be stored, excess protein must be eliminated from the body. This process can interfere with kidney function.
Supplementation Caffeine Much of the evidence relating to caffeine and performance is inconclusive. However caffeine does appear to improve cognitive processes such as alertness, concentration, clear headedness, improved memory and reasoning. Caffeine does not appear to improve the performance in short-term high intensity activities such as sprinting. Some studies also indicate that caffeine acts as a diuretic. A diuretic is a drug that increases the amount of fluid (water and urine) passing from the body. Caffeine has ergogenic aid properties. This means that it has the ability to improve performance by assisting specific metabolic processes. In the case of endurance activities, the ability of caffeine to mobilise fat stores in the body and convert them into free fatty acids is important for energy production.
Supplementation Creatine The body has two sources of creatine, one is produced by body cells and the other is found in meat. Creatine found in the body and eaten from meat is converted to creatine phosphate and thereafter assists in the resynthesis of ATP. It is important in making energy available to sustain short duration explosive activity. While many manufacturers claim its performance enhancing abilities, such as delayed fatigue and sustained energy, increased strength and fat burning properties, research suggests otherwise, finding very little benefit from supplementation. This is because creatine supplementation has very little effect on athletes who are already consuming excessive amounts of protein.
Recovery Strategies Physiological Strategies These strategies aim to address physiological fatigue and tissue damage. Issues such as replenishment of energy supplies, hydration and the dissipation of metabolic by product of competing e.g. lactic acid, are facilitated by techniques such as nutritional recovery plans and appropriate cool downs.
Recovery Strategies Neural Strategies Neural Strategies involve a number of aspects such as the restoration of key neural transmitters, which are chemicals that are used to relay, amplify and modulate signals between a neuron and another cell. Neural recovery can be aided by appropriate hydrotherapy and self massage strategies. A hydrotherapy strategy that is available to most sporting clubs are contrast showers i.e. one minute of hot shower followed by 30 seconds of cold, repeat several times.
Recovery Strategies Tissue Damage Strategies Icing, cold baths, cold ocean dips etc. are popular methods of constricting blood flow to areas of the body which may have suffered soft tissue damage through direct and indirect contact during competition or training.
Recovery Strategies Psychological Strategies Post game relaxation allows the athlete to wind down from the excitement of the game and deal with stress and fatigue. It facilitates sleep and provides a balance by focusing the athlete on issues other than the sport. While relaxation techniques will vary considerable from individual to individual, it is important that athletes learn to disengage their thoughts from their sport at times so that they are psychologically fresh when required to refocus when training resumes.