1. Energy systems.

2. PHYSIOLOGICAL REQUIREMENTS OF PHYSICAL ACTIVITY
Foods
Fuel and
Energy Systems

3. Food Fuels our Body
1. CARBOHYDRATES (Glycogen)
2. PROTEIN
3. FATS

4. CARBOHYDRATES Pastas Cereals Rice Fruit/Veges Breads Sugar
Carbohydrates are stored as Glycogen in Muscle & Liver
CHO is the body’s preferred fuel during Exercise – breaks down easily, uses little oxygen

5. PROTEIN Fish Red Meat Poultry Eggs Dairy products GRAINS
Protein is stored as MUSCLE and AMINO ACIDS around the body.
5-10% contribution to endurance events: Mainly used for growth/repair

6. FATS
Butter
Oils
Margarine
Nuts
Cheese

7. Food that we ingest is stored and burnt to fuel our muscles
This food must be converted into a chemical compound called ATP
Without ATP - Muscles cannot contract

8. ATP is used in all 3 energy systems.
The type of energy system used and the interplay between them depends on the frequency, duration, intensity of the activity and fitness levels of the individual.

9. The 3 energy systems The ATP – PC system The Lactic Acid Systems
Alactacid system
Creatine phosphate system
Phosphagen system.
The Lactic Acid Systems
Anaerobic glycolysis system
Lactacid system
Aerobic System
Aerobic Glycolysis

10. For activity lasting:
0-10 SEC
ATP-PC SYSTEM
10-30/40 SEC
Anaerobic Glycolytic SYSTEM
2MINS +
AEROBIC SYSTEM

11. High Energy Phosphate System

12. ATP-PC SYSTEM CP instantly available, but runs out quickly
Uses stores of CP (Creatine Phosphate) to REMAKE ATP
Used for high intensity Jumps, Throws, Sprints
Only have 10 seconds of CP in muscles
If activity lasts longer than 10 sec, ATP must be REMADE by some other means…..

13. Anaerobic Glycolytic SYSTEM
Body uses stored fuel of GLYCOGEN to REMAKE ATP
Need Oxygen to do this properly
About 2-3 hours of glycogen stored in body.
Downside – by-product called Lactate. Hydrogen Ions also released which inhibit muscle contraction
Happens because of lack of enough Oxygen to break down Glycogen
400m run, 800m at high intensity

14. The Anaerobic Glycolytic System

15. Anaerobic Threshold
The exercise intensity at which lactic acid begins to accumulate within the blood
The point during exercise where the person begins to feel discomfort and burning sensations in their muscles
Lactic acid is used to store pyruvate and hydrogen ions until they can be processed by the aerobic system

16. Used in longer, sub-max activities. Long run, swim, cycle.
AEROBIC SYSTEM
Plenty of Oxygen available to remake ATP . So no LA or H+ is accumulated
Used in longer, sub-max activities. Long run, swim, cycle.
Like the LA system, the Aerobic uses Glycogen to remake ATP.
Oxygen supply meets demand
We use this system at REST (Now!) – except we burn…
Will keep suppling ATP for as long as Fitness levels allow
FAT!!!!

17. Aerobic Oxidative System

18. The Aerobic Oxidative System
The most important energy system in the human body
Blood lactate levels remain relatively low (3-6mmol/L bl)
Primary source of energy (70-95%) for exercise lasting longer than 10 minutes provided that:
a) working muscles have sufficient mitochondria to meet energy requirements
b) sufficient oxygen is supplied to the mitochondria
c) enzymes or intermediate products do not limit the Kreb’s cycle
Primary source of energy for the exercise that is performed at an intensity lower than that of the anaerobic oxidative system

19. Cori Cycle
Lactic acid is taken to the liver to be metabolized back into pyruvic acid and then glucose

20. BUT, need 3 minutes rest to get all CP back!
During REST
Any rest, short OR Long, CP is being replenished, so we can ‘sprint’ again.
BUT, need 3 minutes rest to get all CP back!
Any Lactate and Hydrogen Ions are removed from muscles & blood stream too.

21. All 3 turn on at once no matter what the activity.
Things to remember:
All 3 turn on at once no matter what the activity.
However, depending on intensity and duration of the activity, ONE system will contribute more than the other TWO.
The 3 Energy Systems are not like TRAFFIC LIGHTS. One does not switch off and another goes on.

22. The Role of Three Energy Systems During an All-out Exercise Activity of Different Duration

23. Discussion Questions:
1. What are the differences between the 3 energy systems?
2. List one advantage and one disadvantage of each of the 3 energy systems.
3. Give an example of three activities or sports that use each of (a) the high energy phosphate system, (b) the anaerobic glycolytic system, and (c) the aerobic oxidative system as their primary source of energy (one sport for each energy system).
What is the most important source of fuel in the body for all types of energy production - a substance also known as the energy currency of the body?
5. Describe how each of the three energy systems could be trained most efficiently.