Exercise PhysiologyStudies a range of SYSTEMS in the human body. These systems allow us to perform the various activities we do, and more importantly. enable us to live.

Exercise Physiology requires us to understand the following information:

•Muscular Systems – how they contract & relax and their microscopic structures.•Energy Systems – how we get energy to move.•Circulatory Systems – the heart & blood.•Respiratory System – the lungs•Nervous Systems – the brain & how it controls movement & processes

In this unit we will learn aboutEnergy systems – and how we get energy to move.How our body responds to exercise.The heart and lungs.

The Energy Systems Energy for muscle contractions can be supplied in

two ways: Either 1) Anaerobically – without oxygen, or 2) Aerobically – with oxygen.

In the body there are three main pathways for the breakdown of ATP to make energy. These systems are dependent on the type of activity being performed.

The Three Pathways Are:1. ATP-PC2. Anaerobic – (lactic acid)3. Aerobic

The ATP-PC SystemThis energy system provides energy for the activities of short

duration and high intensity hence it does not require oxygen.

The ATP-PC system will only last up to 10 seconds when there is not any recovery time because the ATP & PC becomes exhausted.

The ATP-PC system is used during 100m sprints, shot put, high-jump and other activities that are completed in only a few seconds.

The Lactic Acid SystemThe Lactic Acid system is also anaerobic (ie. No

Oxygen). It is the system that ‘kicks-in’ when the ATP-PC system can no longer produce energy.

The lactic acid system provides energy for up to 3 minutes hence it is used for activities such as 400m & 800m running events or middle distance swimming. The main source of fuel for this system is Carbohydrates.

One problem with the Lactic Acid system is that a by-product called Lactic Acid builds up in the muscles and blood. It is this by-product produced during intense exercise that causes fatigue.

The Aerobic SystemThe aerobic system produces ATP in the presence of

oxygen. It is this system that is used during rest & everyday activities such as mowing the lawns, walking etc. During intense exercise it is the aerobic system that ‘kicks-in’ after 2-3 minutes.

The aerobic system produces far more ATP than any other system because it is produced when oxygen is present. Not only this, oxygen being present also prevents the build-up of Lactic Acid.

The Three Energy Systems100

50

0

0 10 20 30 40 50 60 120 180 240 300 360Running Time (seconds)

% E

nergy C

ontribution

Red – Green – Pale Blue -

Task – Identify the energy system at work.Activity ATP-PC Lactic Acid Aerobic

Golf Swing

Javelin

Marathon

200m Swim

Volleyball Spike

1500m Run

Walking

30 sec Burst

Power-lifting

Beep Test

Task - AnswersActivity ATP-PC Lactic Acid Aerobic

Golf Swing X

Javelin X

Marathon X

200m Swim X

Volleyball Spike X

1500m Run X

Walking X

30 sec Burst X

Power-lifting X

Beep Test X

Using your notes on energy systems, complete the following table:

Description Source of Energy

Time(predominately

used)

Classification Example

ATP – PC(immediate)

Lactic Acid(short term)

Aerobic(long term)

AnswersDescription Source of

EnergyTime

(predominately used)

Classification Example

ATP – PC(immediate)

Used in high intensity, extremely short

activities.

ATP stored in the muscle cells.

0-10 sec Anaerobic(Does not require O2, and so does not cause

a build up of lactic acid).

Sprint starts, weight lifting, shot put…

Lactic Acid(short term)

Used in short term, high intensity exercise.

Carbohydrates(glycogen)

30 sec – 2 mins Anaerobic(Does not require O2, but used carbos only,

large amounts of lactic acid build up-hence

decreased performance).

200m sprint, sit ups/ press ups…

Aerobic(long term)

Light – moderate intensive exercise.

(The body can work for extended time

without experiencing fatigue).

Carbohydrates and fats.

2-3mins + (These intensive may vary

from very easy to very hard)

Aerobic(Because this system requires oxygen to

burn carbos and fats, lactic acid does not build up-hence no

effect on performance).

Marathon runner or swimmer…

Summary of Energy Systems

ATP-PC System Lactic Acid System Aerobic System

Anaerobic Anaerobic Aerobic

Very rapid Rapid Slow

Chemical: CP Food: glycogen Food: CHO, Fat,Protein

Very limited ATP Limited ATP Unlimited ATP

Muscular stores Lactic Acid causes No fatiguing limited fatigue by-products

Explosive, sprint 30 sec to 3 min Endurance

100m 400m Marathon