HSC PDHPE Core 2:Factors Affecting Performance

• Nutritional Considerations

“An athlete’s body must be fuelled appropriately if the athlete is to maintain optimal training regimes and give themselves the opportunity to compete at their best. A person’s energy expenditure will also influence the number of kilojoules they need to consume – elite athletes who train more than five hours a day require more full than sedentary people. A stable body weight and muscle mass are the best indicators that energy intake matches need. When we do not consume sufficient energy, there is a reduction in weight and/or in lean mass as the body tries to compensate for this deficiency. Research indicates that athletes should eat frequently throughout the day.”

PROTEIN INTAKE:“Training commitments only lead to a small increase in protein requirements for most athletes – that is 1 gram per kilogram of body weight compared to 0.8 grams for a sedentary person – unless they are endurance or strength athletes in a heavy phase of training , and therefore need additional protein (1.4 -1.7 grams per kilogram of body weight) for muscle growth and repair).

CARBOHYDRATE INTAKE:“It has been suggested that athletes who train at least 20 hours a week need 7 grams of carbohydrate per kilogram of body weight, while a recreational athlete training 3-5 hours per week needs 4-5 grams of carbohydrate per kilogram of body weight.

“The nutritional routine for any athlete will encompass what should be consumed before, during and after their performance. It is highly recommended that athletes develop a competition nutritional plan for all major events, and make sure they have tested the strategies they will use before, during and after their event.

A major cause of fatigue and decline in performance is the depletion of fuels (in particular glycogen stores in the muscles). Therefore one of the main aims of pre-performance nutrition is ‘fuelling up’ and supplying enough carbohydrates to maximise the body’s glycogen stores in the final 24-36 hours before an event. This is extremely important for both endurance and high intensity events.”

“Pre-performance nutrition can take into consideration nutritional intake in the days and hours immediately prior to performance.

• Nutritional Considerations- Pre performance:

Two key purposes of pre-performance nutritional intake are:1.To ensure that the body is well hydrated. Dehydration can lead to a decrease in blood volume and this will inhibit performance.2.To ensure that the body has sufficient glycogen stores for use during the performance so as to minimise the potential for fatigue. Glycogen is the form in which carbohydrates are stored in the body, and glycogen is critical for generating energy in both endurance and high intensity activities”.

“Carbohydrate loading is a strategy used mostly by endurance athletes to increase carbohydrate consumption in the days and hours prior to performance as a way of increasing the amount of glycogen stored in their body. Foods and fluids that are high in carbohydrate , but lower in fat and fibre are consumed in greater amounts than usual in small, frequent meals.

Examples of foods and fluids that might be consumed for carbohydrate loading include:•Pasta•Bread•Cereal•Low-fat milk/yoghurt•Banana’s•Sports Drinks

“When carbohydrate loading is done in conjunction with tapering, which is when the athlete reduces their training level substantially, endurance performances can improve by 2-3%. Tapering means gradually reducing training before an event to allow the body to recover from stress”.

In sports or events lasting up to 60 minutes, carbohydrate loading is typically undertaken 24-36 hours prior to performance.

In sports or events lasting up to 90 minutes, carbohydrate loading is typically undertaken 36-72 hours prior to performance.

“The pre-performance meal is ideally consumed 3-4 hours prior to performance. The purpose is to:•Address current feelings of hunger and reduce the likelihood of feeling hungry during the performance•Top up glycogen stores•Ensure the athlete remains well hydrated

Pre-performance meals are ideally ones that are consumed regularly prior to performance. This reduces the risk of having an adverse reaction and the familiar routine can help breed confidence in the athlete and help them to begin to ‘switch on’ mentally for the upcoming performance.

• Nutritional Considerations- Pre performance:

•Nutritional Considerations- Pre performance:

• Nutritional Considerations- During performance:

“Rehydration and refuelling may be needed during performance. At the most basic level, it is generally accepted that small, frequent sips of water during performance is a sensible way to keep the body in a hydrated state during performance.

Effective fluid replacement is achieved by increasing intake before, during and after performance. Guidelines for fluid replacement include:•BEFORE – At least 24 hours prior to performance, fluid intake should be increased. In the two hours prior to performance, approximately 500mL should be consumed. Fifteen minutes prior to performance, approximately 200-300mL should be consumed.

•“DURING – Small, frequent drinks should be consumed, enough to replace the water lost through sweating. A practical suggestion is 200-300 mL every 15-20 minutes.•AFTER – Approximately 200-300 mL of fluid should be consumed for every 15-20 minutes of exercise.

The possibility of dehydration is greater on hot days and greater still when the day is hot and humid. High humidity reduces the effectiveness of evaporation as a means of heat loss. As such fluid replacement needs at these times are greater.

Water is the fluid most recommended for consumption during sports performance . Debate continues regarding the suitability of sports drinks, but water is undeniably effective for all durations and intensities of exercise.

“There is, however, some evidence to suggest that certain sports drinks may provide additional benefit in high intensity physical activities lasting beyond 30-60 minutes. Sports drinks that contain 4-8% of carbohydrates such as glucose and sucrose (but not fructose) may assist in delaying the onset of fatigue and enhancing the intestinal absorbtion of water. Similarly sports drinks with sodium content of 0.5-0.7 grams per litre may help replace electrolytes lost in sweat.

Refuelling by consuming carbohydrates to replenish glycogen stores is more likely to become important in activities of longer duration, typically 60 minutes or more. Useful sources can include bananas, sports bars, carbohydrate gels and sports drinks”.

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• Nutritional Considerations- Post performance:

“Post performance nutrition is the first step in the recovery process and ultimately in preparing for the next training session or performance. The key purposes of post performance nutrition are to:•Rehydrate the athlete•Replenish Glycogen•Rebuild Muscle Tissue

Post performance consumption typically includes water and/or sports drinks for rehydration and a combination of carbohydrates and protein for glycogen replenishment and rebuilding muscle.

http://www.ausport.gov.au/ais/nutrition