1. Energy systems and their role in sport and exercise
Physiology of Fitness
Energy systems and their role in sport and exercise

2. Learning Outcomes
List the 3 main energy systems and their cellular fuel
Describe the 3 energy systems giving sports related examples
Explain why some sports require more of one energy system than another
Measure and record the body’s responses to different types of exercise
Explain the recorded measurements
Produce a short magazine article describing the three main energy systems using examples.

3. Actin & Myosin What are the contractile proteins in muscle?
The key terms to remember from that clip are:
ATP
ADP + Creatine Phosphate
Myosin
Actin
When ATP is released onto myosin the chemical bond breaks releasing a lot of energy causing actin and myosin filaments to contract ie muscle contraction
Contractile proteins

4. The release of energy from ATP
What is ATP?
ATP is a protein (Adenosine) with 3 phosphates attached to it
When chemical bonds are broken, energy is released and ATP becomes ADP (Adenosine diphosphate Di=2)
The energy from this breaking is used to make muscles contract
The release of energy from ATP

5. Energy Systems
What are the 3 main energy systems that convert chemical fuel from food into energy?
Creatine Phosphate System
Lactic Acid System
Aerobic Energy System
What is this?
The mitochondrion, shown here, is a tiny cellular structure that turns chemical fuel into cellular energy ie ATP.

6. Creatine Phosphate System

7. Creatine Phosphate System
CP System
(immediate energy)
Here ATP is made without the presence of oxygen.
When exercise intensity is high, or energy needs are instantaneous, creatine phosphate stored in your muscle is broken down to provide energy to make ATP.
Explosive work can be achieved, but only for short periods of time at maximum intensity, as the supply of creatine phosphate is very limited, up to 10 seconds.
Activity
List as many sports activities as possible that use mainly the CP system.

8. Creatine Phosphate System
Primary energy source:
Duration of activity:
Sporting events:
Advantages:
Limiting factors:
Stored ATP, CP
7-12 s
Weight lifting, high jump, long jump, 100m run, 25m swim
Produce very large amount of energy in a short amount of time
Initial concentration of high energy phosphates (ATP, PC)

9. Creatine Phosphate System

10. Training The CP System
a) Interval training: eg 1min low intensity 1min high intensity & repeat
- 20% increase in CP (creatine phosphate) stores
- no change in ATP stores
- increase in ATPase function (ATP -> ADP+P)
- increase in CPK (creatine phosphokinase) function (CPK breaks down CP molecule and allows ATP resynthesis)
b) Sprint training:
- increase in CP stores up to 40%
- 100% increase in resting ATP stores

11. Lactic Acid Energy System

12. Lactic Acid Energy System
high intensity exercise
up to 2 minutes.
ATP is made by the partial breakdown of glucose and glycogen. This is caused by anaerobic glycolysis
It’s an anaerobic process (no O2)
Where does the body store glycogen?
Muscles
Liver
What is the by-product of anaerobic glycolysis?
Lactic acid

13. Lactic Acid Energy System
Primary energy source:
Duration of activity:
Sporting events:
Advantages:
Limiting factors:
Stored glycogen, blood glucose
12 s – 3 min
Lactic acid build up, H+ ions build up (decrease of pH)
800m run, 200m swim, downhill ski racing, 1500 speed skating
Ability to produce energy under conditions of inadequate oxygen

14. Lactic Acid Energy System

15. Lactic Acid Energy System
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. Lactic Acid Energy System
The primary source of substrates is carbohydrate
Carbohydrates:
primary dietary source of glucose
primary energy fuels for brain, muscles, heart, liver

17. Aerobic Energy System Primary energy source: Duration of activity:
Sporting events:
Advantages:
Limiting factors:
Glycogen, glucose, fats, proteins
> 3 min
Lung function, max.blood flow, oxygen availability, excess. energy demands
Walking, jogging, swimming,
walking up stairs
Large output of energy over a long
period of time, removal of lactic acid

18. Aerobic Energy System

19. Aerobic Energy System

20. Aerobic Energy 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

21. Aerobic Energy System
Long term energy, system for light exercise and every day movements.
Uses O2
The production of energy in the aerobic system does not start instantly.... Why?
In groups discuss this and write down your agreed answer
Answer: It takes a few minutes for the heart to deliver oxygenated blood to the working muscles. Long, continuous moderate exercise produces energy using this system.

22. Types of Sport that use each system
Remember, energy at any given time is derived from all 3 energy systems.
However the emphasis changes depending on:
the intensity of the activity
the efficiency of your aerobic fitness

24. Energy Systems Summary
Creatine Phosphate energy system ... for very short high intensity exercise
ADP + Phosphocreatine ATP + creatine
requires no O2 but only enough stored for about 10secs e.g. power lifting...
Lactic Acid Energy System: short-term energy system
Glucose 2 ATP + 2 lactic acid + heat
Glycogen 3 ATP + 2 lactic acid + heat
requires no O2 but produces energy for high intensity exercise for up to 60 – 90 secs e.g. 400m race..

25. Energy Systems Summary
3. Aerobic Energy System: long-term energy system
Glucose +O ATP + CO2 + water + heat
Fatty acids + O ATP + CO2 + water
+ heat

26. Activity
Produce a magazine article that describes and explains the body’s energy systems to a football coach.
What are the differences between the 3 energy systems?
List one advantage and one disadvantage of each of the 3 energy systems.
Give an example of three activities or sports that use each of (a) the creatine phosphate system, (b) the lactic acid system, and (c) the aerobic 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?