Define ‘energy’, ‘work’, and ‘power’.Define ‘energy’, ‘work’, and ‘power’. Identify examples of potential, chemical and Identify examples of potential, chemical and

kinetic energy within the body.kinetic energy within the body. The role of ATP within the body and explain how The role of ATP within the body and explain how

energy is made available for muscular contraction.energy is made available for muscular contraction. Describe the three energy systems for ATP re-Describe the three energy systems for ATP re-

sythesissythesis Identify the thresholds of each of these systems.Identify the thresholds of each of these systems. Explain the term ‘OBLA’Explain the term ‘OBLA’ Explain the factors that determine how these Explain the factors that determine how these

systems combine to provide energy for different systems combine to provide energy for different sporting activities.sporting activities.

Energy is the ability to perform work.Energy is the ability to perform work.

Energy is measured in Joules (J)Energy is measured in Joules (J)

It is also measured in caloriesIt is also measured in calories 1 calorie = 4.18 joules1 calorie = 4.18 joules

total intake of food sufficient to total intake of food sufficient to supply enough energy to :supply enough energy to :

keep cells alivekeep cells alive keep systems workingkeep systems working meet demands of lifemeet demands of life

Neutral energy balance:Neutral energy balance:

Energy input = Energy outputEnergy input = Energy output Negative Energy balance:Negative Energy balance:

Energy output > Energy inputEnergy output > Energy input Balanced diet and regular aerobic exercise is the Balanced diet and regular aerobic exercise is the

most effective means of weight control.most effective means of weight control. Basal Metabolic Rate = the rate at which energy Basal Metabolic Rate = the rate at which energy

is used by basic bodily functions (@ rest or is used by basic bodily functions (@ rest or sleeping)sleeping)

Total Metabolic Rate = the rate at which energy is Total Metabolic Rate = the rate at which energy is used by all bodily functions including exerciseused by all bodily functions including exercise

   FOODFOOD KILOJOULES KILOJOULES PER GRAMPER GRAM

KILOCALORIES KILOCALORIES PER GRAMPER GRAM

FATFAT 3737 99

ALCOHOLALCOHOL 2929 77

PROTEINPROTEIN 1717 44

CARBOHYDRATESCARBOHYDRATES 1616 44

  Calories in:Calories in:

a 100g bar of Cadbury's Dairy Milk: 530kcala 100g bar of Cadbury's Dairy Milk: 530kcal

a pack of Maltesers: 183kcal a pack of Maltesers: 183kcal

a Mars Bars (65g): 294kcala Mars Bars (65g): 294kcal

A 30g bowl of Corn Flakes: 112 cal A 30g bowl of Corn Flakes: 112 cal

Check outCheck out

www.whatsinsideguide.comwww.whatsinsideguide.com www.brianmac.co.uk/energyexp.htmwww.brianmac.co.uk/energyexp.htm www.weightlossresources.co.uk/calorwww.weightlossresources.co.uk/calor

ies/calorie_counteries/calorie_counter www.bmi-www.bmi-calculatorcalculator.net.net

WORK = force x distance movedWORK = force x distance moved

Force = a push or pull that alters, or tends to alter, the Force = a push or pull that alters, or tends to alter, the state of motion of a body. Measured in Newtons.state of motion of a body. Measured in Newtons.

measured in joules (J)measured in joules (J)

WORK = force x distance movedWORK = force x distance moved A rugby players spear tackles a A rugby players spear tackles a

stationary 95kg opponent. He stationary 95kg opponent. He drives him back 2 metres? How drives him back 2 metres? How much work did he do before he much work did he do before he was sent off and banned for 3 was sent off and banned for 3 months?months?

is the rate at which we can work is the rate at which we can work or work/timeor work/time

the energy used per secondthe energy used per second POWER = work/timePOWER = work/time Considered a combination of Considered a combination of

strength and speedstrength and speed unit = watt (W)unit = watt (W)

ATP is adenosine triphosphate.ATP is adenosine triphosphate.

This compound is the only immediately This compound is the only immediately usable form of energy stored in our usable form of energy stored in our bodies.bodies.

We have other energy rich compounds We have other energy rich compounds such as phosphocreatine and such as phosphocreatine and glycogen.glycogen.

CHEMICAL ENERGYCHEMICAL ENERGY is energy that is produced by a complex series of is energy that is produced by a complex series of

chemical reactionschemical reactions Stored as …..Stored as ….. which can then be made available as :which can then be made available as :KINETIC ENERGYKINETIC ENERGY is energy due to movementis energy due to movement which results from muscular contractionswhich results from muscular contractionsPOTENTIAL ENERGYPOTENTIAL ENERGY is stored energy waiting to happen.is stored energy waiting to happen. eg. ATP does nothing until P group is released eg. ATP does nothing until P group is released

with the help of ATPase.with the help of ATPase.

However, ATP is the only one that can be However, ATP is the only one that can be utilised by the muscles to create utilised by the muscles to create movement.movement.

ATP is stored within the muscle cellATP is stored within the muscle cell Total mass of 85g within the bodyTotal mass of 85g within the body Enough to last for about 2 seconds of Enough to last for about 2 seconds of

exercise.exercise. To maintain exercise, ATP has to be re-To maintain exercise, ATP has to be re-

synthesised from adenosine diphosphate synthesised from adenosine diphosphate (ADP) and a phophate group (‘P’ of ‘Pi’)(ADP) and a phophate group (‘P’ of ‘Pi’)

Adenosine

Adenosine

P P P

P P

P

ATPase

High-energy bond

The energy is stored in the The energy is stored in the bond between the last two bond between the last two phosphate groups.phosphate groups.

When this bond is broken When this bond is broken

by the action of the by the action of the enzyme ATPase, energy is enzyme ATPase, energy is released that can be used released that can be used by the muscle cell to by the muscle cell to contract.contract.

ATP re-synthesis is achieved by 3 energy ATP re-synthesis is achieved by 3 energy systems:systems: The Phosphocreatine systemThe Phosphocreatine system Lactic acid systemLactic acid system Aerobic systemAerobic system

The amount of ATP re-synthesis is done by The amount of ATP re-synthesis is done by each system will depend purely on the each system will depend purely on the intensity of the exercise.intensity of the exercise. Two systems can be working at the same time.Two systems can be working at the same time.

This system uses another high-energy compound known as This system uses another high-energy compound known as phosphocreatine to provide energy to combine ADP and P.phosphocreatine to provide energy to combine ADP and P.

PC = P + C + energy (exothermic)Energy + ADP + P = ATP (endothermic)

AdvantagesAdvantages DisadvantagesDisadvantages

• 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

• There is only a small amount of PC stored in the muscle cells.

• O2 is not required, therefore there is no delay

to wait for oxygen to be supplied from the lungs

• Only one mole of ATP is re-synthesised from one mole of PC

• It can provide energy for very high-intensity exercise.

• It will only provide energy for a maximum of ten seconds

• Recovery times for this system are very quick, as PC will re-synthesise quite quickly.

• There are no harmful by products that will cause fatigue.

Another anaerobic systemAnother anaerobic system takes place in the sarcoplasmtakes place in the sarcoplasm

The fuel used is CHO.The fuel used is CHO. Stored in the muscles and liver as glycogen.Stored in the muscles and liver as glycogen.

CHO is converted to glucose by the enzyme CHO is converted to glucose by the enzyme glycogen phosphorylaseglycogen phosphorylase and undergoes a series of and undergoes a series of reactions known as reactions known as anaerobic glycolysis.anaerobic glycolysis.

This is started by the enzyme This is started by the enzyme phosphofructokinase phosphofructokinase (PFK)(PFK) until eventually it is converted into pyruvic until eventually it is converted into pyruvic acid.acid.

During this process 2 moles of ATP are re-During this process 2 moles of ATP are re-synthesised.synthesised. Due to the lack of oxygen, the pyruvic acid is converted to Due to the lack of oxygen, the pyruvic acid is converted to

lactic acid by the enzyme lactic acid by the enzyme lactodehydrogenase.lactodehydrogenase.

Glucose

Lactic acid Pyruvic acid

PFK

LDH

2 ATP

AdvantagesAdvantages DisadvantagesDisadvantages

• There is a relatively large supply of glycogen stored in our bodies and so ths system can supply more ATP than the PC system

• 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.

• ATP can be provided quickly for high-intensity activities that last from anywhere from 15-180 secs.

• O2 is not required, therefore there is no

delay to wait for oxygen to be supplied from the lungs

Requires Oxygen as a fuel alongside glycogen or fat to re-Requires Oxygen as a fuel alongside glycogen or fat to re-synthesise ATPsynthesise ATP

First part of the system is identical to the lactic acid First part of the system is identical to the lactic acid system.system.

However the pyruvic acid is not converted into lactic acid. However the pyruvic acid is not converted into lactic acid. Instead it is taken by the co-enzyme Instead it is taken by the co-enzyme acetyl CoAacetyl CoA into the into the Kreb’s Cycle.Kreb’s Cycle.

Here a series of chemical reactions occurs, further Here a series of chemical reactions occurs, further breaking down the CHO compound. breaking down the CHO compound. This takes place in the matrix of the mitochondria.This takes place in the matrix of the mitochondria.

Once this series of reactions is completed, Carbon Dioxide Once this series of reactions is completed, Carbon Dioxide and Hydrogen ions are produced.and Hydrogen ions are produced. The CO2 is removed via the lungsThe CO2 is removed via the lungs The hydrogen ions enter the The hydrogen ions enter the electron transfer chain.electron transfer chain.

This occurs in the cristae of the mitochondria.This occurs in the cristae of the mitochondria. Electrons are removed from hydrogen and passed down Electrons are removed from hydrogen and passed down

the elctron transfer chain providing energy to resynthesise the elctron transfer chain providing energy to resynthesise 34 moles of ATP.34 moles of ATP. The hydrogen is combined with oxygen to produce water.The hydrogen is combined with oxygen to produce water.

Glucose

Lactic acid Pyruvic acid

PFK

LDH

2 ATP

Kreb’s Cycle

Acetyl CoA

2 ATP2 CO2

Electron

transfer chain

H

24 ATP

0 2

H20

e-

Sarcoplasm

Mitochondria (cristae)

Mitochondria (matrix)

AdvantagesAdvantages A large amount of

ATP can be resynthesised

36 to 38 moles can be produced from one mole of glycogen.

Activity can last for hours

There are no harmful by-products of the chemical reactions

DisadvantagesDisadvantages Due to the need for Due to the need for

oxygen, the system oxygen, the system cannot resynthesise cannot resynthesise ATP immediately; ATP immediately; there is a delay there is a delay while oxygen is while oxygen is transported from transported from the lungsthe lungs

Cannot provide ATP Cannot provide ATP whilst working at whilst working at higher intensities.higher intensities.

The threshold of any system is the point at The threshold of any system is the point at which that energy system is unable to which that energy system is unable to provide energy.provide energy. PC systemPC system

Approx. 10 secondsApprox. 10 seconds Lactic Acid systemLactic Acid system

Approx. 15 -180 secsApprox. 15 -180 secs Aerobic systemAerobic system

Onset of Blood lactate accumulation (OBLA)Onset of Blood lactate accumulation (OBLA) When blood lactate levels goes above 4mmol per litre When blood lactate levels goes above 4mmol per litre

or the point at which there is a rapid increase in this or the point at which there is a rapid increase in this value.value.

OBLA ranges from 50% VOs max in untrained OBLA ranges from 50% VOs max in untrained individuals to 85% VO2 max in highly trained athletes.individuals to 85% VO2 max in highly trained athletes.

Due to increased ability to remove waste products Due to increased ability to remove waste products and supply oxygen to working muscles.and supply oxygen to working muscles.

In an given situation our energy In an given situation our energy systems rarely work in isolation.systems rarely work in isolation. E.g a footballerE.g a footballer

Movement at low intensity whilst jogging back Movement at low intensity whilst jogging back into positioninto position

Sudden high intensity movement – break Sudden high intensity movement – break down the wing.down the wing.

Energy is provided by all three Energy is provided by all three systems, and the contribution is systems, and the contribution is determined by the intensity and the determined by the intensity and the duration of exercise.duration of exercise.

Duration of maximal exerciseDuration of maximal exercise

SecondsSeconds MinutesMinutes

10 3030 6060 22 44 1010 3030 6060 121200

90 80 70 50 35 15 5 2 1

10 20 30 50 65 85 95 98 99

Percentage anaerobic

Percentage aerobic

00

1010

2020

3030

4040

5050

6060

7070

8080

9090

100100

100100

9090

8080

7070

6060

5050

4040

3030

2020

1010

00

AerobicAerobic AnaerobicAnaerobic

100m sprint100m sprint

200m sprint200m sprint

100m swim100m swim

boxingboxing

800m800m

1500m / hockey game1500m / hockey game

400m swim400m swim

rowing 2000mrowing 2000m

3000m run3000m run

Cross-country runCross-country run

MarathonMarathon

Adapted from Davis et al (2005) - Physical Education and the study of Sport

Carnell et al (2002), Advanced PE for Carnell et al (2002), Advanced PE for OCR ASOCR AS

Davis et al (2005), Physical Davis et al (2005), Physical Education and the Study of Sport.Education and the Study of Sport.