The essential nutrients required by all athletes include:

CHO Protein Fat Minerals Fibre Vitamins Water

Each sport has different nutritional requirements.

No set dietary regime will cater for all athletes’ individual needs

Enjoy a variety of foods and make choices specific to individual sporting events

High CHO foods should contribute to a high proportion of daily intake

Professional athletes begin to prepare months before a major competition

Optimise food and fluid intake before, during and after training to simulate the demands of competition

Pre event meals can mean the difference between winning and losing

Carbohydrate loading Keep well hydrated Food needs to be consumed in time for it to be digested and

absorbed and needs to coincide with the exercise period Healthy meal 3-4 hrs before exercise Or a light snack 1-2 hrs before exercise Pre exercise meals should increase CHO levels and be low in

fat and moderate in fibre to aid digestion. Foods higher in fat, protein and fibre take longer to digest –

risk of gastric upsets

Foods rich in CHO’s play a vital role in exercise performance – they are most readily available and a versatile source of energy

High-intensity, short-durations activities As a guideline 7 – 10 grams of CHO per kg of body mass is

appropriate for an athlete CHO stores need to be continually topped up to ensure

there is enough in the muscles before the start of training and competition

CHO should make up 55-65% of total daily food intake

Situation Recommended CHO intake

Daily refuelling needs for training programs less than 60-90 min per day or low intensity exercise

Daily intake of 5-7 g/kg BM

Daily refuelling for training programs greater than 90-120 min per day

Daily intake of 7-10 g/kg BM

Daily refuelling for athletes undertaking extreme exercise program - 6-8 hours per day (cycling tour)

Daily intake of 10-12+ g/kg BM

Carbohydrate loading for endurance and ultra-endurance events

Daily intake of 7-10 g/kg BM

Pre-event meal Meal eaten 1-4 hours pre-competition 1-4 g/kg BM

Carbohydrate intake during training sessions and competition events greater than 1 hour

1 g/min or 30-60 g/hour

Rapid recovery after training session or multi-day competition, especially when there is less than 8 h until next session

Intake of 1-1.5 g/kg BM for every hour in the early stages of recovery after exercise, contributing to a total intake of 6-10 g/kg BM over 24 hours

Indulge in CHO’s in the days leading up to a competition Needs to be considered in conjunction with the glycaemic index

of foods Used to maximise stores of muscle and liver glycogen prior to

endurance competition. Benefits those exercising continuously for 90mins or longer Shorter events are unlikely to benefit as the body’s usual CHO

stores are adequate to cope No practical when games are player every three to four days and

adequate refuelling opportunities exist Originally the practice involved a depletion phase (glycogen

stripping). Was thought to stimulate the enzyme glycogen synthase. Glycogen stripping was performed in conjunction with CHO loading which was thought to boost CHO stores (supercompensation). No longer used.

Attempts to prolong CHO’s as the main fuel source and delay the body’s reliance on fats

High CHO diet = 70 – 75% of total dietary intake

Improves endurance exercise because athletes can exercise at their optimal intensity for a longer time.

Can improve performance by 3-5% Exercise Tapering – a decrease in training load that is

common before a game to facilitate recovery and optimal fuel storage.

Tapering lessons the likelihood of injury

CHO loading attempts to prolong CHO’s as the main fuel source and delay the body’s reliance on fats

The breaking down of fats decreases power output as aerobic breakdown is significantly slower, therefore ATP is resynthesised at a slower rate

‘hitting the wall’ – feelings of pain and fatigued associated with glycogen depletion

When performing at 70-80% max HR, oxidation of blood glucose occurs at 1 gram per minute (60 grams/hr)

It is important to understand that: CHO loading requires exercise taper It can be hard to train lightly for 3 or 4 days before comp. Failure to rest will compromise CHO loading It can be hard to eat enough CHO’s Work with a sport dietitian

Necessary to cut back on fibre and use concentrated sources of CHO

Body mass will increase by approx 2kg in an average 70kg athlete

Important to consume high CHO low fat foods

Complete ‘Thinking things through’ on page 323 of your textbook

Read the article on page 323 ‘My gut has been blown out of proportion: Hackett’

50 – 80 grams of CHO should be consumed during recovery, starting immediately after exercise, repeated 2 hourly for the first 6 hrs after exercise.

For the first 2 hrs after exercise, blood it rushing to the muscles and muscle cells still take up glucose and enzymes are receptive to converting glucose to glycogen.

Best time to eat moderate to high GI foods and for drinking sports drinks

If CHO consumption after exercise is delayed, full replenishment may take several days

Copy Table 12.2 on page 324 of your text book

Proteins and fats are low GI because they contain no CHO and have minimal effect on glucose production

High fibre foods are low GI as they increase the time it takes our bodies to break down foods

GI ranks foods on a scale of 0 – 100 according to how much they raise blood sugar over a 2 hr period compared to pure glucose

Knowledge of GI allows athletes to determine what CHO foods to eat and when to eat them

High GI foods – replenish CHO stores quickly Moderate to high GI foods, gels or drinks consumed during

extended endurance activities increase CHO availability Low GI foods – should be consumed before competition or

training ‘Glycogen Sparing’ – a long term adaptation that allows fats to be

used more readily and earlier during performance Familiarise yourself with table 12.3 on page 325 of your

textbook What athletes can only benefit from a pre event meal?

Events lasting longer than 90 – 120 mins need to ensure they maintain adequate CHO supplementation during the event

What products are a good idea to consume in this case? Generally, athletes should aim to shift their dietary choices towards

foods with a low GIQUESTIONS CHO’s are broken down into simpler forms to be transported

and stored in the body. Name these forms and where they are found.

Discuss the types of activities CHO’s provide energy for and provide 3 specific sporting examples for each type of activity.

State the %tage of CHO intake recommended daily for athletes.

How much CHO should an athlete consume per kg of body mass?

Define the term Glycaemic index. Discuss how knowledge of the glycaemic index of foods can

help an athlete. Explain why foods with a low GI are appropriate for pre-event

meals.

Sweating is the bodies method of keeping the core temperature at around 37 degrees Celsius, which results in the loss of plasma fluids and electrolytes

This can lead to dehydration and related heat stress performance decrements

Copy Table 12.4 on page 326 of your textbook Fluid serves many important functions;

To transport energy, waste, hormones and antibodies To dilute waste products To lubricate surfaces and membranes To help regulate body temp To be involved in all chemical reactions in the body

Dehydration is a major cause of fatigue Athletes should consume approx 200-600 millilitres prior to

an event and replace approx 500-100 millilitres per hr during the actual event

Athletes should consume 200-300 millilitres every 15-20 minutes if possible

Replacing fluids is an integral part of the recovery process In endurance exercise, as much as 6L can be lost through sweat To assess the required amount of fluid needing to be replaced,

compare pre and post exercise weight changes. Each kg of body weight lost is equivalent to 1L of fluid lost 150% of fluid deficit should be consumed 2-4hrs after exercise Electrolytes also need to be restored

SPORTS DRINKS Formulated to rehydrate the body, replace electrolytes and

refuel CHO’s Electrolytes – salts used by muscles, nerve and heart cells to

maintain voltages across their membranes and to carry electrical impulses across them

Electrolytes are important in fluid regulation in and out of body structures

Movement of water across cell membranes is reliant on electrolyte concentration either side of the membrane

ISOTONIC DRINKS: Same osmolality (the concentration of a solution in terms of

number of particles) as the body’s own fluids, containing comparable amounts of CHO and electrolytes

Preferred by athletes for their balance of refuelling and rehydration

Most widely used The sodium also aids in the retention of consumed fluidsHYPOTONIC DRINKS: Low osmolality, containing lower concentrations of CHO and

electrolyte particles Absorbed faster than isotonic drinks Suitable for athletes that need quick fluid replacement without the added boost of electrolytes orenergy from CHO’s

HYPERTONIC DRINKS: More concentrated and have a higher osmolality than the

body’s own fluids Absorbed slowly and have are relatively high in CHO’s Can be used to supplement daily CHO intake and are typically

used after exercise to top up muscle glycogen stores Consumed during ultra distance events Need to be consumed in conjunction with Isotonic drinks to

replace fluids

TYPE CONTENT

Isotonic Fluid, 6-8% CHO, 10-25 mmol/L electrlytes (eg. Gatorade)

Hypotonic Fluid, low level of CHO (<8%), 1-25 mmol/L electrolytes (eg. water)

Hypertonic Fluid, high level of CHO (>8%) (eg. fruit juice, soft drink)

Water is absorbed faster than sports drinks, but it dilutes the levels of electrolytes and doesn’t provide any energy replenishment.

Drinking water alone during exercise results in reduced thirst before enough fluid has been consumed for adequate rehydration.

Water stimulates urine output and causes bloating

ENERGY DRINKS Sports drinks and water are very different to energy drinks Current research shows that energy drinks have no impact of

sporting performance

2 factors affect the speed at which fluid from a drink gets into the body1 – the speed at which it is emptied from the stomach to the duodenum

(gastric emptying)2 – rate at which it is absorbed through the walls of the small intestine to

the blood (intestinal fluid absorption)

The higher the CHO levels in a drink, the slower the rate of stomach emptying

Athletes need to avoid rises in core temperature Acclimatisation is an important strategy Strategies used to prevent ‘heat stress’ are:- ‘Heat Tolerance’ can be developed by training in warm

conditions- Modify training and competition to suit the level of fitness

and environmental conditions- Train in early mornings or late afternoons and avoid the

hottest part of the day (11am – 3pm)- Wear light coloured clothing or lightweight and loose fitting

clothing- Drink adequate fluid before, during and after exercise Familiarise yourself with Table 12.6 on page 330 of

your textbook

CHO gels are essentially dehydrated sports drinks (concentrated without the water

They come in small foil packets and contain 24 – 28 grams of CHO

One packet provides 400 – 600 kilojoules of energy Gels must be consumed with water or they will not be

absorbed quickly enough to top up fuel stores Gels and sports bars should not be taken together when high

sweat rates occur because the large increase in CHO concentration results in slowing of hydration rates.

Familiarise yourself with Tables 12.7 & 12.8 on page 333 of your textbook

Oral hydration is the drinking and consumption of fluids via the mouth

IV hydration is the administration of fluid through the vein IV hydration restores lost body fluids more quickly and

effectively than drinking the same amount Disadvantage of drinking before an event is the associated

feeling of fullness, which can be avoided by obtaining the same amount of fluid intravenously

IV hydration is banned by some sporting bodies but accepted by others

Disadvantages: requires a hygienic condition to administer and there is a risk of over hydration which can lead to kidney damage

Describe how you can check if you are taking in enough fluid.

Explain the difference between each of the 3 sports drinks

Compare the difference between sports drinks, sports water and energy drinks.

Explain the underlying rationale behind the use of IV drips as a means of rehydrating athletes after competition or training.

Explain why sports drinks are the preferred source of rehydration in comparison to water.

Compare each type of sports drink and include the following information: type, CHO concentration, type of athlete suited to and other considerations

Read pages 335-340 and summarise the following:Dietary SupplementsCaffeine SupplementationCreatine supplementation and loadingProtein SupplementationBicarbonate and citrate

QUESTIONS Discuss the nutritional and fluid requirements of an Australian

rules footballer;1. Before the game2. During the game3. During Training4. During Recovery

Discuss the dietary and fluid considerations for a swimmer. Complete all review questions on pages 348 & 349 of your

textbook.