Energy Conversion + Nutrition Flashcards
What are the two systems through which ATP is released in anaerobic exercise?
The Phosphagen System (Alactacid System)
The ATP is instantly released from within the muscles but the supply can only be sustained for a short period of intense work up to 8 seconds. There are no adverse effects from this process.
The Lactic Acid System (Anaerobic Glycolisis)
During intensive exercise lasing up to 45 seconds, the ATP is released by the processes of glycolisis within the muscles. A bi-product of this process is lactic acid which accumulates in the muscle, restricting the production of ATP which results in muscle fatigue and discomfort.
A warm down or cool down period following anaerobic exercise is essential to: allow the lactic acid to be dispersed, to reduce the discomfort and start the process of energy regeneration.
Why is exercise recovery helpful after gymnastics training?
The intense loading of gymnastic training generates high lactic acid concentrations due to the involvement of the glycolisis processes.
It is therefore recommended that all gymnastic training sessions are concluded with a cool down period which will allow the lactate to be used as substrate in the active muscles to partly replace the glycogen and glucose stores.
What are the guidelines for post training replenishment of energy stores?
Muscle glycogen synthesis is at it’s peak within the first two hours following exercise and it is recommended that complex carbohydrates (starch) with a high glycaemic index are taken immediately following training.
It is recommended that the optimal rate of replenishment is 50g of carbohydrate every two hours (i.e. 200 – 400 calories within the first two hours and 200 – 300 calories in the next few hours).
What does the term ‘High Glycaemic Index’ refer to and what are the key recommendations?
The glycaemic index (GI) provides an indication of how quickly carbohydrates are digested and absorbed to increase the blood glucose levels. The GI compares the rise in glucose produced with the level of blood glucose produced by 50g of glucose. The value of glucose is given a reference of 100 and the other foods ranked accordingly with the higher value foods raising the blood glucose more rapidly.
Recommendations
1 - Eat high GI foods for a quick boost of carbohydrates during and immediately after training
2 - Eat medium GI foods for pre-competition meals
3 - Eat low GI foods in the evening to avoid fat storage
4 - Eat low GI foods when a reduction in body fat is required.
Explain your understanding of the recommended proportions of
carbohydrates, protein and fat in the gymnast’s diet.
The recommended proportions of energy providing food in a gymnast’s diet are:
Carbohydrates: 62%
Protein: 16%
Fat: 22% as a % of the total calorific intake
It is also possible to calculate the recommended daily carbohydrate intake according to body weight and level of activity as follows:
- Formula to work out the recommended daily carbohydrate intake (for high level of activity)
= 8kg x (body weight in kg) = (grammes of carbohydrate/day) - Formula to calculate the daily calorific intake of carbohydrates.
= (Grammes of carbohydrate/day) x4 = kcal (of carbohydrate/day)
How does Aerobic exercise affect the process through which ATP is generated and utilised
Aerobic Exercise (with Oxygen) In low intensity exercise the glycogen in the muscles and the liver is broken down by the presence of oxygen into ATP to supply chemical energy. This form of energy release can be sustained over long periods of light exercise and is particularly useful in endurance work.
How does Anaerobic exercise affect the process through which ATP is generated and utilised
As the intensity of exercise is increased the metabolic threshold of aerobic energy release is reached and the reserve energy supply of the anaerobic system is recruited. Hence in short bouts of exercise, the energy potential of the aerobic system is quickly outstripped and the anaerobic system is called upon. The anaerobic system does not require oxygen to release the ATP. It utilises the resources stored within the muscles.
There are two systems through which ATP is anaerobically released:
1 - The Phosphagen System (Alactacid System)
The ATP is instantly released from within the muscles but the supply can only be sustained for a short period of intense work up to 8 seconds. There are no adverse effects from this process.
2 - The Lactic Acid System (Anaerobic Glycolisis)
During intensive exercise lasing up to 45 seconds, the ATP is released by the processes of glycolisis within the muscles. A bi-product of this process is lactic acid which accumulates in the muscle, restricting the production of ATP which results in muscle fatigue and discomfort.
What are the guidelines for pre-exercise diet?
Guidelines for carbohydrate intake suggest it should be distributed evenly throughout the day, but there are particular needs before the training session.
Prior to training or competition, the carbohydrate intake should ideally follow the schedule:
i) 3 – 4 hours before training, 5g of carbohydrate per kg of body weight.
ii) 1 hour before event, 1 – 2g of carbohydrate per kg of body weight of foods with 60% carbohydrate energy content and high glycaemic index, 300-500 ml of fluid with 6 – 10% carbohydrate may also be taken
iii) 15 – 20 minutes before exercise, a high carbohydrate snack or carbohydrate drink may be taken
What are the guidelines for during event diet?
In order to maintain adequate hydration and to enhance the rate of water absorption and minimise fatigue levels, 100-200 mls of water containing 6 – 8% carbohydrate solution may be taken every 10 – 15 minutes.
