Nutritional considerations Supplementation Recovery strategies

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 body’s 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 body’s 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 athlete’s 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 body’s 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 body’s 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.