Energy systemsLearning outcomes: All are able to demonstrate understanding
of the relationship between OBLA and VO2max
Most are able to explain the third energy system (the aerobic system)
Most are able to apply the recovery process to sport
Some can analyse the causes of fatigue
Starter ActivityUsing mini white boards answer the following
questions.
What is another term for the maximum volume of oxygen that can be consumed by the muscles per minute?
Name an accurate method to measure this?State one factor that can affect this?At what point does OBLA typically occur?Trained endurance performers can delay OBLA until what
% of their VO2max?What is the name of the process that helps remove lactic
acid and maintain blood and muscle pH?Name a factor that influences the rate of lactate
accumulation.
HomeworkComplete Energy systems summary sheetComplete examination questions on EPOC.Research and make notes on carbohydrate
loading, hypoglycaemia and fluid loss replenishment.
Aerobic systemLow intensity activities with a duration of
longer than 1-2 minutes use the aerobic system
The aerobic system is a complex chain of events consisting of three stages.
Watch Video clips and add details to homework sheet on Aerobic system
aerobic system
Stage 1: GlycolysisOccurs in the
sacroplasmAerobic conditions so
no lactic acid producedPyruvic acid converted
to acetyl coenzyme A (CoA)
the energy released from the breakdown of each molecule of glucose is used to make two molecules of ATP
Stage 2: Krebs Cycle• Takes place in the
matrix of the mitochondria
• hydrogen is removed and taken to electron transport system
• carbon dioxide is produced as a waste product
• The energy yield is two molecules of ATP
Stage 3: Electron transport chain
• It occurs in the cristae of the mitochondria
• Water is formed (hydrogen ions and electrons combine)
• The energy yield is 34 molecules of ATP
Mini plenaryComplete the diagrammatic representation
of the aerobic pathway .
Equation to summarise:
C6H12O6 + 6O2 6CO2 + H2O + ENERGY ENERGY 38ADP + 38Pi 38ATP
Aerobic SystemAdvantages DisadvantagesMore ATP can be
produced aerobically than anaerobically (36 rather than 2ATP)
Body has enough stores of muscle glycogen and triglycerides to exercise for several hours
No fatiguing by products
Cannot provide energy to resynthesise ATP in the immediate short term
Transport of fatty acids is slow and requires about 15% more oxygen to break down than glycogen
Endurance athlete needs to use a combination of glycogen and fatty acids.
Hitting the wall.You have probably heard this expression what
does it mean?
Glycogen is depletedBody tries to use fatty acids as its only sourceMuscle spasms may occur.
Causes of fatigueUsing a spider diagram use the knowledge you have
gained over the last few weeks to explain some causes of fatigue.
Glycogen depletion
Lactic acid build up
Reduced rate of ATP synthesis
Dehydration
Reduced level of calcium
Reduced levels of acetylecholine
Causes of FatigueGlycogen depletion – When glycogen stores are depleted athletes
are said to ‘hit the wall’ as the body tries to metabolise fat.
Lactic acid build up – Accumulation of Lactic acid releases hydrogen ions. Increases acidity of blood plasma. Inhibits enzyme action.
Reduced rate of ATP synthesis – ATP & PC stores are insufficient.
Dehydration – Effect blood flow to working muscles, Blood viscosity increases and blood pressure decreases
Reduced level of calcium – Increase of hydrogen ions decreases the amount of calcium released.
Reduced levels of acetylcholine – inhibits nervous impulses
The Recovery ProcessUsing your notes prepared for homework
write 5 questions that you could give to somebody to demonstrate their knowledge of the recovery process.
Give to a partner and get them to answer them.
Pass back and use a green pen to mark it.
The Recovery Process1. What is meant by the term recovery?2. Explain the term excess post-exercise
oxygen consumption (EPOC).3. What is the oxygen deficit?4. What are the two stages of recovery?5. Draw a diagram that illustrates the oxygen
consumption during and following exercise.
The Recovery Process1. the return of the body to its pre-exercise
state.2. the extra volume of oxygen consumed
during recovery that enables the body to fully recover
3. When we start exercising insufficient oxygen is distributed to the tissues so the two anaerobic systems are used. The amount of oxygen that the subject was short of is known as the oxygen deficit. This is compensated by the surplus oxygen.
The Recovery process4. The fast replenishment stage
(alactacid) – Restoration of ATP and Phosphocreatine stores. Resaturate myoglobin. Takes 2 – 3 mins
The slow replenishment stage (lactacid) – The removal of lactic acid (about 1hr). O2 also used to maintain cardiac and respiratory rates and normalise body temp. Replenish muscle glycogen stores.
The Recovery process5.
Recovery processUse handout to ensure you fully understand
this process. Add any additional notes required to this.
PlenaryUsing the following terms explain the
recovery process:
EPOC Alactacid Lactacid
Oxygen deficit Recovery
