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Define ‘energy’, ‘work’, and ‘power’.
Identify examples of potential, chemical and kinetic energy within the body.
The role of ATP within the body and explain how energy is made available for muscular contraction.
Describe the three energy systems for ATP re-sythesis
Identify the thresholds of each of these systems.
Explain the term ‘OBLA’
Explain the factors that determine how these systems combine to provide energy for different sporting activities.

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Energy is the ability to perform work.
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Energy is measured in Joules (J)
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It is also measured in calories
1 calorie = 4.18 joules

 total intake of food sufficient to supply enough energy to :
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 keep cells alive keep systems working meet demands of life

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Neutral energy balance:
Energy input = Energy output
Negative Energy balance:
Energy output > Energy input
Balanced diet and regular aerobic exercise is the most effective means of weight control.
Basal Metabolic Rate = the rate at which energy is used by basic bodily functions (@ rest or sleeping)
Total Metabolic Rate = the rate at which energy is used by all bodily functions including exercise

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FOOD
FAT
ALCOHOL
PROTEIN
CARBOHYDRATES
29
17
KILOJOULES
PER GRAM
37
KILOCALORIES
PER GRAM
9
16
7
4
4

a 100g bar of Cadbury's Dairy Milk: 530kcal a pack of Maltesers: 183kcal a Mars Bars (65g): 294kcal
A 30g bowl of Corn Flakes: 112 cal

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 www.whatsinsideguide.com
www.brianmac.co.uk/energyexp.htm
www.weightlossresources.co.uk/calories/c alorie_counter www.bmi-calculator.net

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Force = a push or pull that alters, or tends to alter, the state of motion of a body. Measured in Newtons.
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ATP is adenosine triphosphate.
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This compound is the only immediately usable form of energy stored in our bodies.
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We have other energy rich compounds such as phosphocreatine and glycogen.

CHEMICAL ENERGY
 is energy that is produced by a complex series of chemical reactions
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Stored as …..
which can then be made available as :
KINETIC ENERGY
 is energy due to movement which results from muscular contractions
POTENTIAL ENERGY
 is stored energy waiting to happen.
 eg. ATP does nothing until P group is released with the help of ATPase.

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However, ATP is the only one that can be utilised by the muscles to create movement.
ATP is stored within the muscle cell
Total mass of 85g within the body
Enough to last for about 2 seconds of exercise.
To maintain exercise, ATP has to be resynthesised from adenosine diphosphate
(ADP) and a phophate group (‘P’ of ‘Pi’)

Adenosine P
Adenosine P
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The energy is stored in the bond between the last two phosphate groups.
P
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When this bond is broken by the action of the enzyme
ATPase, energy is released that can be used by the muscle cell to contract.
P
High-energy bond
P
ATPase

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ATP re-synthesis is achieved by 3 energy systems:
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The Phosphocreatine system
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Lactic acid system
Aerobic system
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The amount of ATP re-synthesis is done by each system will depend purely on the intensity of the exercise.
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Two systems can be working at the same time.

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This system uses another high-energy compound known as phosphocreatine to provide energy to combine ADP and P.
PC = P + C + energy (exothermic)
Energy + ADP + P = ATP (endothermic)
Advantages
• Provides ATP re-sythesis very quickly because the PC is stored in the sarcoplasm of the muscle cell and there are very few steps in the reaction
•
O
2 is not required, therefore there is no delay to wait for oxygen to be supplied from the lungs
• It can provide energy for very high-intensity exercise.
• Recovery times for this system are very quick, as PC will re-synthesise quite quickly.
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There are no harmful by products that will cause fatigue.
Disadvantages
• There is only a small amount of PC stored in the muscle cells.
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Only one mole of ATP is re-synthesised from one mole of PC
• It will only provide energy for a maximum of ten seconds

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Another anaerobic system
 takes place in the sarcoplasm
The fuel used is CHO.
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Stored in the muscles and liver as glycogen.
CHO is converted to glucose by the enzyme glycogen phosphorylase and undergoes a series of reactions known as anaerobic glycolysis.
This is started by the enzyme phosphofructokinase (PFK) until eventually it is converted into pyruvic acid.
During this process 2 moles of ATP are re-synthesised.
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Due to the lack of oxygen, the pyruvic acid is converted to lactic acid by the enzyme lactodehydrogenase.

Glucose
PFK 2 ATP
Lactic acid Pyruvic acid
LDH
Advantages
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There is a relatively large supply of glycogen stored in our bodies and so ths system can supply more ATP than the
PC system
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ATP can be provided quickly for highintensity activities that last from anywhere from 15-180 secs.
•
O
2 is not required, therefore there is no delay to wait for oxygen to be supplied from the lungs
Disadvantages
•
The bi-product, lactic acid, reduces the pH of the muscle cell, making it more acidic; this prevents the enzymes from functioning properly, causing fatigue.

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Requires Oxygen as a fuel alongside glycogen or fat to resynthesise ATP
First part of the system is identical to the lactic acid system.
However the pyruvic acid is not converted into lactic acid. Instead it is taken by the co-enzyme acetyl CoA into the Kreb’s Cycle.
Here a series of chemical reactions occurs, further breaking down the CHO compound.
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This takes place in the matrix of the mitochondria.
Once this series of reactions is completed, Carbon Dioxide and
Hydrogen ions are produced.
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The CO2 is removed via the lungs
The hydrogen ions enter the electron transfer chain.
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This occurs in the cristae of the mitochondria.
Electrons are removed from hydrogen and passed down the elctron transfer chain providing energy to resynthesise 34 moles of ATP.
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The hydrogen is combined with oxygen to produce water.

Lactic acid
2 CO
2
0
2
Glucose
PFK 2 ATP
LDH
Pyruvic acid
Acetyl CoA
Sarcoplasm
Kreb’s Cycle 2 ATP
Mitochondria
(matrix)
H e -
24 ATP
Electron transfer chain
H
2
0
Mitochondria
(cristae)

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Advantages
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A large amount of ATP can be resynthesised
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36 to 38 moles can be produced from one mole of glycogen.
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Activity can last for hours
There are no harmful by-products of the chemical reactions
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Disadvantages
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Due to the need for oxygen, the system cannot resynthesise
ATP immediately; there is a delay while oxygen is transported from the lungs
Cannot provide ATP whilst working at higher intensities.

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The threshold of any system is the point at which that energy system is unable to provide energy.
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PC system
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Approx. 10 seconds
Lactic Acid system
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Approx. 15 -180 secs
Aerobic system
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Onset of Blood lactate accumulation (OBLA)
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When blood lactate levels goes above 4mmol per litre or the point at which there is a rapid increase in this value.
OBLA ranges from 50% VOs max in untrained individuals to
85% VO2 max in highly trained athletes.
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Due to increased ability to remove waste products and supply oxygen to working muscles.

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In an given situation our energy systems rarely work in isolation.
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E.g a footballer
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Movement at low intensity whilst jogging back into position
Sudden high intensity movement – break down the wing.
Energy is provided by all three systems, and the contribution is determined by the intensity and the duration of exercise.

Percentage anaerobic
Percentage aerobic
10
90
10
Duration of maximal exercise
Seconds Minutes
30 60 2 4 10 30 60 120
80
20
70
30
50
50
35
65
15
85
5
95
2
98
1
99

100m sprint
200m sprint
100m swim boxing
800m
1500m / hockey game
400m swim rowing 2000m
3000m run
Cross-country run
Marathon
Aerobic
40
50
60
70
0
10
20
30
80
90
100
Anaerobic
60
50
40
30
100
90
80
70
20
10
0
Adapted from Davis et al (2005) - Physical Education and the study of Sport

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Carnell et al (2002), Advanced PE for OCR
AS
Davis et al (2005), Physical Education and the Study of Sport.