Physiology of Fitness

Energy systems and their role in sport and exercise

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.

 

Chemical fuel• Your body’s ability to extract energy from food and

transfer it to the contractile proteins in your skeletal muscle determines your capacity to exercise at different durations at different intensities. This transfer of energy occurs as a result of thousands of chemical reactions.

• The muscles use a fuel called • ATP (adenosine triphosphate).

ATP

Energy is stored in the chemical bond

ATP = A-P-P--P

When this bond is broken energy is released – allowing myosin to attach to actin and muscle contraction to occur.

ADP = A-P-P P = ADP will then bind again with a phosphate

group and energy is stored that can be used later.

Lots of energy stored between 2nd & 3rd phosphate groups

Phosphate (creatine phosphate)

Actin & Myosin• What are the

contractile proteins in muscle?

• Actin & Myosin

http://www.youtube.com/watch?v=gJ309LfHQ3M

http://www.physics3110.org/images/240_actin.gif

• 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

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

Energy Systems• What are the 3 main

energy systems that convert chemical fuel from food into energy?

1. Creatine Phosphate System

2. Lactic Acid System

3. Aerobic Energy System

What is this?

The mitochondrion, shown here, is a tiny cellular structure that turns chemical fuel into cellular energy ie ATP.

Creatine Phosphate SystemCP 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.

ActivityList as many sports activities as possible that use mainly the CP system.

Lactic Acid Energy System• This is for high

intensity exercise lasting 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

• http://www.youtube.com/watch?v=JLaVIPlPm6g&feature=related

Recap

Lactic Acid Energy System

Anaerobic g________ is the breakdown of ________ and _________ to produce _ _ _

This energy system can sustain high intensity exercise for how long? _____

The by product is called _______ ____. It can impede muscle contraction and cause fatigue.

Creatine Phosphate Energy System

It is the imm_________

energy system needed when exercise intensity is ______, or energy needs are instantaneous.

C_______ p________ is broken down to provide energy to make _ _ _

When ATP is released onto m______ the chemical bond breaks releasing a lot of energy causing a____ and m_____ filaments to contract ie muscle contraction

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.

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