Energy systems Learning 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 Activity Using 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.

Homework Complete Energy systems summary sheet Complete examination questions on EPOC. Research and make notes on carbohydrate loading, hypoglycaemia and fluid loss replenishment.

Aerobic system Low 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: Glycolysis Occurs in the sacroplasm Aerobic conditions so no lactic acid produced Pyruvic 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 plenary Complete the diagrammatic representation of the aerobic pathway . Equation to summarise: C6H12O6 + 6O2  6CO2 + H2O + ENERGY ENERGY  38ADP + 38Pi  38ATP

Aerobic System Advantages Disadvantages More 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 depleted Body tries to use fatty acids as its only source Muscle spasms may occur.

Causes of fatigue Using 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 Fatigue Glycogen 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 Process Using 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 Process 1. 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 Process 1. 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 process 4. 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 process 5.

Recovery process Use handout to ensure you fully understand this process. Add any additional notes required to this.

Plenary Using the following terms explain the recovery process: EPOC Alactacid Lactacid Oxygen deficit Recovery