1. Nutrition for Exercise and Sport Energy Systems Applying the Principles of Nutrition to a Physical Activity Programme

2. Session aims Identify ATP as the energy currency
Revise the characteristics of the three energy systems: 
Fuels
Duration
Intensity
Describe the contribution of different fuels in ATP production at different exercise intensities:
Carbohydrates
Fats
Proteins (gluconeogenesis)
Creatine phosphate

3. ATP: The energy currency
High energy compound essential for muscle contraction
Cannot be stored, therefore a continual supply on demand is essential
ATP can be made by three energy systems

4. Energy systems – complete the table
Fuel
Duration
Intensity
Considerations CP
Lactic acid
Aerobic system

5. Energy systems – summary
Fuel
Duration
Intensity
Considerations CP
Creatine stored in the muscle
Sections
Maximum
The potential duration of this system is dependant on the individual’s fitness level and training
Lactic acid
Glycogen stored in the muscle
Minutes
Moderate − High
As above. Through
training we are able to
increase the capacity of this system. This enables us to work at a higher intensity for longer and extend the
duration of this system.
Aerobic system
Predominantly fat with the assistance of carbohydrates
Ongoing
Low − Moderate
Fitness level and effective fuelling will effect an
individual’s aerobic capacity.

6. Contribution of different fuels in ATP production
Carbohydrate and fat are used to produce ATP
Exact proportions depend on the conditions
Protein is not normally used to produce energy unless glycogen stores are low.
Protein from muscle can be broken down to release glucose for energy (gluconeogenesis)
Creatine phosphate – present in small amounts inside the muscle can also be used to generate ATP for high intensity exercise

7. Fat or carbohydrate?
Carbohydrate is stored in in the liver and muscles in the form of glycogen.
Fat used during exercise comes from fat stored all over the body underneath the skin, and needs to be transported to muscles by the blood
Carbohydrate and fat are usually used in combination
High intensity, anaerobic exercise of short duration will predominantly rely on carbohydrate, as fat cannot be used in the absence of oxygen
Aerobic exercise will use different mixtures of fat and carbohydrate depending on the intensity

8. Exercise for Nutrition and Sport Eating for Energy Applying the Principles of Nutrition to a Physical Activity

9. Learning outcomes
Describe where carbohydrate and fat are stored on the body and in what quantities
State the role of both muscle and liver glycogen
Explain the onset of gluconeogenesis during prolonged exercise
List factors that affect glycogen storage
Describe how long glycogen stores can last
List strategies to maximise glycogen stores
Provide guidelines to ensure effective fuelling and refuelling for exercise

10. Stores of carbohydrate (glycogen)
Energy stores
Stores of fat
(adipose tissue)
Stores of carbohydrate (glycogen)
Liver =60 – 100g (240 – 400kcals)
Muscle =200 – 400g (800 – 1600kcals) 
Total = 1040 – 2000kcal
Body Weight = 60kg (female)
% Body fat = 20% (i.e. very lean)
Weight of fat = 12kg or 12,000g
Fat kcal = 12,000 x (9kcal per gram of fat)
= ,000 kcal

11. Glycogen stores
Glycogen stored in each muscle cell is for the exclusive use of that muscle cell and cannot be transferred
Liver glycogen stores are primarily reserved to maintain blood glucose levels
If blood glucose falls the brain stimulates hunger in order to obtain fuel, or triggers glycogen breakdown
During prolonged exercise the brain stimulates the use of amino acids from muscle tissue to convert to glucose - gluconeogenesis

12. Factors affecting glycogen storage
Time of day (glycogen will depleted first thing in morning & after exercise)
Fitness/training level (trained muscle better at storing glycogen)
Lean muscle mass (more muscle = more glycogen storage capacity)
Diet (consistent high carbohydrate intake is essential to replenish glycogen stores)

13. How long can glycogen store last?
Moderately hard activity glycogen stores will last approximately minutes
Normal day-to-day activity: 4-5 hours

14. Strategies to maximise glycogen stores
Pre training
Ensure you top up your carbohydrate stores every 4 – 5 hours.
Eat small regular meals to reflect your activity levels throughout the day.
Aim to consume most of your kcal when you are more active
Do not go for long periods of time without eating. If you are very hungry you tend to consume the wrong type of food.
Do not exercise on an empty stomach, i.e. first thing in the morning.
Aim to consume a light meal up to 2 hours prior to training or a larger meal 2 – 4 hours prior to training.
Aim to consume low GI foods throughout the day to ensure a steady supply of carbohydrate energy.
High GI foods may be beneficial immediately prior to activity to provide an immediate supply of energy.

15. Strategies to maximise glycogen stores
During Activity
If your activity/training session lasts more than 90 minutes ensure you consume carbohydrates during the session.
Aim to consume approximately 20g of carbohydrates every 30 minutes.

16. Strategies to maximise glycogen stores
Post activity
After exercise consume enough carbohydrates to get your stores back up
Consume them as soon as possible after your training session has finished
The window of opportunity to refuel after exercise lasts up to 2 hours
Research suggests that 15mins post‐exercise is the optimal time to refuel
Females aim to refuel with 40–50 g of carbohydrates.
Males aim to refuel with 60–80 g of carbohydrates
Be realistic with the duration and intensity of the training session. If your session is low intensity and of short duration your refuelling requirements will be lower