We need a constant supply of energy, even at rest.

During exercise more energy will be required.

The energy needed will vary with the demands of the activity.

Three Forms of EnergyThree Forms of Energy

Light from the sun is converted by plants intostored chemical energy.

Humans consume the plants or animals who eat the plants, this is then stored as potential

energy (ATP).

Muscles use this energy for movement this is Kinetic Energy.

Energy = The ability or capacity to perform work

ie muscle contractionsMeasured in JoulesJoules

Work done is done when a force is applied to a body to move it over a distance.

Work = force x distance movedforce x distance moved

Power = The rate at which we perform workPower = work (force x distanceforce x distance )

------- Time (seconds)

Power is measured in Watts

Only 1 usable form of energy:

All food needs to be converted into ATP before potential energy can be used.

= 1 molecule of Adenosine and 3 phosphates

= High-energy simple phosphate compound

When a compound is BROKEN DOWN energy is released.

Exothermic reaction

The enzyme that breaks down ATP is ATPase

ATP is broken down toAdenosine Diphosphate

(ADP) and a free phosphatereleasing the stored energy

ATP ADP + P + Energy

When a compound is BUILT UP, energy is needed to restore the bonds between the

molecules

Endothermic reaction

ADP + P + Energy ATP

1. Phosphocreatine system(Alacticacid system)

2. Lactic Acid system(Anaerobic Glycolysis)

3. The Aerobic System

We don’t want to run out of ATP!

Therefore all three systems work quickly.

They are good at supplying energy for different intensities and for different

durations of activity.

Systems 1 & 2 = AnaerobicSystem 3 = Aerobic

• ATP Found in sarcoplasm (equivalent to cytoplasm)• Potential energy stored in bonds of the compound• Enzyme creatine kinase breaks down PC• Creatine kinase is activated when ATP stores start to diminish and there is a high level of ADP in the muscle cell

Phosphocreatine (PC) P + Creatine + Energy

creatine kinase

The energy created by the breakdown of PCis used to resynthesis ATP from ADP.

This is known as acoupled reaction

Reaction 2 relies on reaction1PC P + C +Energy

Energy + ADP + P = ATP

• The stores of PC in the muscle is enough to sustain maximum effort for 10 seconds.

• This is the only system that can produce ATP quick enough in events where we are working maximally, ie triple jump and sprinting

• PC is a very easy compound to break down. As it is stored in the muscle cells, it is readily available and does not need oxygen.

• ATP can be made quickly with no fatiguing waste products

Training Adaptations

• Need to do anaerobic training• Overloaded ATP/PC system• Increases muscle store of ATP/PC• Delays threshold between ATP/PC and lactic acid system• Increases potential of duration 1-2 seconds more

Give the advantages and disadvantages of ATP/PC system using pg 370

Aim to provide energy to allow ADP to resynthesise into ATP

Coupled reactionAlso takes place in the Sarcoplasm

Partial breakdown of glucose (need oxygen for full breakdown)

Glycolysis = breakdown of glucose/glycogen into pyruvic acid

Carbohydrate stored as glycogen in the Carbohydrate stored as glycogen in the liver and muscleliver and muscle

Glycogen phosphorylase

Glucose-6-phosphate

Phosphofructokinase

Pyruvic Acid

Lactate dehydrogenase

Lactic Acid

ATP

2 ATP

Glucose Glycogen

• Provides energy to resynthesise ATP for first 2-3 minutes of high intensity short duration anaerobic activity.• Flat out intensity it may only last for 30 seconds.• Its limitation is due to onest of blood lactate accumulation (OBLA).• Build up of lactic acid decreases ph of muscle which then inhibits enzymes needed for glycolysis• Muscle fatigue occuirs.

Onset of blood lactate Onset of blood lactate accumulationaccumulation is the point is the point

at which blood lactate at which blood lactate becomes extensive becomes extensive enough to suppress enough to suppress

performance.performance.OBLAOBLA depends on the depends on the

level of training.level of training.

Onset Of Blood Lactate Accumulation (OBLA)Onset Of Blood Lactate Accumulation (OBLA)

TRAINING ADAPTIONSTRAINING ADAPTIONS

RegularRegular anaerobic training anaerobic training which which overload LA systemoverload LA system

increases body's tolerance to increases body's tolerance to lactic acid and increases lactic acid and increases

stores of glycogen.stores of glycogen.Delays OBLA.Delays OBLA.Delays fatigue.Delays fatigue.

Give the advantages and disadvantages of the LA system, You may find pg 372

table 3 helpful.

Break down of glycogen, glucose and fats to provide energy, via coupled reactions to

resynthersies ADP into ATP.

3 stages:

a)Aerobic Glycolysisb) Krebs’ Cycle

c) Electron Transport Chain

a) Aerobic Glycolysis

Similar to lactic acid system BUT:

Glucose is fully broken down due to the presence of OXYGEN!

PYRUVIC ACID moves in to theNo build up of lactic acid.

Krebs’ Cycle

2 ATP

b) Krebs’ Cycle Pyruvic Acid

Coenzyme A

Acetyl CoA

Mito

chon

dria

(m

atrix

)

Oxaloacetic Acid Citric Acid

Carbon Dioxide

Hydrogen

2 ATP

Krebs’ Cycle

Hydrogen Ions(Charged with potential energy)

c) Electron Transport Chain

Energy is released in a step by step manner.The hydrogen ion-electron pairs are passed down

from ahigh level of energy to a lower level of energy.

Thus producing

34 ATP

Water+

Mi to

c hon

dri a

(c r

ista

e)

3 stages:

a) Aerobic Glycolysis =

b) Krebs’ Cycle =

c) Electron Transfer Chain =

2 ATP

2 ATP

34 ATP

38 ATP

For better diagram see pg 373-374

Give the advantages and disadvantages of the LA system, you may find pg 375 table 4 helpful.

Summary of Aerobic systemUses oxygen

Fuels used – carbohydrate and fatsDominant during low intensity / long duration activities.Involves the complete breakdown of glucose and fats

with the presents of oxygen.

Which yields more energy break down of fats or glycogen? Why? (Pg 376)

Training Adaptations

Aerobic training causes adoptions to be made which help to improve the efficiency of the aerobic system.

• Increases storage of muscle and liver glycogen• Increases mobilisation of aerobic enzymes• Is able to use free fatty acids (broken down

triglycerides by lipases) earlier, this conserves glycogen stores.

Look at the following activities, what is the difference in the rate of energy needed to complete these athletics events?

100m400m1500m10,000m

Two keywords can be used to describe the difference an activity needs:

IntensityDuration

Anaerobic or Aerobic?

Anaerobic activities:High intensityShort duration

Aerobic activities:Low intensityLong duration

PC or alactic systemDominant during flat out activities lasting

10seconds

Lactic acid or anaerobic glycolysisDominant during high intensity activities

lasting 30seconds -3minutes

Anaerobic Systems

Give a definition for each of the following key wordsATP, ADP

Alactic / PC SystemLactic Acid / Anaerobic Glycolyis System

Aerobic SystemEnzyme, Coupled reaction, Threshold

Dominant system, Energy yield

ATP = Adenosine TriphosphateAdenosine -- Phosphate -- Phosphate -- Phosphate

(energy within the bonds)Only useable source of potential energy

Enough stored for 2 seconds of energy productionEnergy released by breaking one of the phosphate

bonds by ATPaseATP ADP + P + Energy

This is an exothermic reaction (energy released)

After 2secs all the ATP will have been broken down to ADP

Since it is the only source of energy ATP must be reformed.

ADP + P + Energy = ATP(endothermic reaction)

This reaction relies on energy being available.This energy is provided by the ENERGY

SYSTEMS. All examples of COUPLED reactions

Factor Description

Potential Energy source Creatine Phosphate (PC)

Site of Reaction Sarcoplasm of muscle cell

Enzyme used Creatine Kinase

Reaction PC P + C + Energy

Energy used to reform ATP

Energy Produced 1 ATP reformed

Threshold 10 seconds

Activities Explosive, 100m sprint etc

Factor Description

Energy Source Glycogen / Glucose

Site of Reaction Sarcoplasm of muscle cell

Breakdown of Glycogen Glycogen / Glucose

Enzyme used Glycogen phosphorylase

Breakdown of Glucose Glucose split – pyruvic acid

Enzyme used Phosphofructose kinase

Enzyme used to convert to lactic acid

Lactate Dehydrgenase

Energy produced 2 ATP’s

Threshold 60 secs

Aerobic Glycolysis Similar as anaerobic glycolysis

Full breakdown of glucose

Energy yield 2ATP’s

Net result Production of pyruvic acid which in the presence of

oxygen is transported to the mitochondria (stage 2)

Description Pyruvic acid combines with oxaloacetic acid to form citric acid, enters Kreb’s cycle

Site of Reaction Matrix of the mitochondria

Net result Carbon dioxide produced

2 ATP’S reformed

Hydrogen given off

Description Hydrogen is charged

H+ + e-

Electrons passed down a chain of reactions which releases a lot of

energy

Site of reaction Cristae of mitochondria

Net result 38 ATP’s produced

Water produced

Overall energy yield Stage 1 = 2ATP’S

Stage 2 = 2ATP’s

Stage 3 = 34ATP’S