1. Energy Continuum. Aims:
To understand the implications the intensity of exercise has upon the energy re-synthesis requirements.
To understand the key theories linked with the energy continuum.

2. Energy continuum.
“The relative contribution of each energy system to ATP re-synthesis determined by the intensity and duration of exercise”
What does this mean?
Each energy system provides Differing levels of ATP re-synthesis, the intensity and duration of exercise determines, which energy system is most predominant in providing ATP. Note- they do not work in isolation!!

3. Task. Activity % PC % Lactic % Aerobic Shot putt Marathon 800m Tennis
Consider the activity and state what percentage of energy will be provided by each energy system.
Justify your answer!!
Activity
% PC
% Lactic
% Aerobic
Shot putt
Marathon
800m
Tennis
Netball centre

4. Thresholds.
The threshold of any system is the point at which it cannot provide energy.
The threshold for the PC system is the point it cannot provide energy for the working muscles (Usually after 10 seconds).
What about the aerobic threshold, when is it reached?

5. Onset of Blood Lactate Accumulation (OBLA).
“The point at which the concentration of lactic acid in the blood rapidly increases”.
Lactic acid levels:
Normal aerobic work = 1-2mmol of lactic acid per litre of blood.
OBLA = 4mmol per litre of blood. (anaerobic work).

6. When does OBLA occur?
OBLA varies depending on the aerobic fitness of the performer. In untrained individuals this may occur at 50% of their Vo2 Max.
In highly trained athletes this may be as high as 85% of their Vo2 max, due to their ability to dispose of waist products (lactic acid).
Vo2 max = the maximum amount of O2 you can take into your body and utilise for exercise.
Consider two identical twins both with the same Vo2 Max, one is trained the other is not. They both race to the shops, who will experience OBLA first?

7. Exam question.
Athletes often use a mix of three energy systems to re-synthesis ATP during an activity. Explain the term energy continuum and, using an example from PE, illustrate when and why an athlete would switch from one energy system to another. [4 marks].
1 mark = explain.
1 mark = example.
1 mark = when it switches.
1 mark = why it switches.

8. Homework
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