2Energy can be defined as the capacity to do work! Learning ObjectivesTo understand the different energy systemsTo understand each energy systems use in sport and exerciseREMEMBEREnergy can be defined as the capacity to do work!
3Grading CriteriaP7 – Describe the three different energy systems and their use in sport and exercise activitiesM4 – Explain the three different energy systems and their use in sport and exercise activitiesD2 – Analyse the three different energy systems and their use in sport and exercise activities
4Unit ContentEnergy systems – Phosphocreatine; Lactic Acid; Aerobic energy systemAmount of ATP produced by each systemsSports that use these systems to provide energyRecovery time
6Energy SystemsThe use of each system depends on the intensity and duration of each activity:If the activity is short in duration (less than 10 seconds) and high intensity, we use the ATP-PC systemIf the activity is longer than 10 seconds and up to 3 minutes at high intensity, we use the lactic acid systemIf the activity is long in duration and submaximal pace, we use the aerobic system
7Energy ContinuumSometimes we need to use all three systems to regenerate ATP because the demands of an activity are varied. For example, in rugby:A short sprint to tackle a player uses the ATP-PC systemA long sprint the length of the pitch to score a try uses the lactic acid systemPositional play will use the anaerobic system
8Adenosine Triphosphate (ATP) ATP is vital for muscle contraction it is the only form of useable energy in the bodyThe body only has enough ATP stored for 1 explosive act (about 3 seconds)After that there is none leftThen energy has to be created by other meansATP (1 explosive act) = ADP (adenosine phosphate)
9ATP – Adenosine TriPhosphate High energy bondATP – Adenosine TriPhosphateADENOSINEPHOSPHATEPHOSPHATEPHOSPHATEADP – Adenosine DiPhosphateENERGYADENOSINEPHOSPHATEPHOSPHATEPHOSPHATE
10Phosphocreatine Energy System (ATP/PCr System) ADP + Creatine Phosphate (PCr) = ATPLasts about 10 secondsHigh intensity maximum workExtremely efficientDoes not need oxygenHas no waste productsThink 100 meters
11ATP-PC System Advantages Phosphocreatine stores can be regenerated quickly (50% replenishment in 30 s; 100% in 3 mins)No fatiguing by-productsCreatine supplementation extends the time that the ATP–PC system can be utilisedDisadvantagesThere is a limited supply of phosphocreatine in the muscle cells, i.e. it can only last for 10 sOnly 1 molecule of ATP can be regenerated for every molecule of PCPC regeneration can only take place in the presence of oxygen (i.e. when the intensity of the exercise is reduced)
12Lactic Acid Energy System ADP + Glucose = ATPWhen PCr runs out, the muscles call upon stores of glucose (glycogen).Lasts between seconds.Has a waste product called pyruvic acidIf not enough oxygen is breathed in to break pyruvic acid down (oxygen debt) it converts into lactic acidThis is also called anaerobic glycolysisThink 400m
13Lactic Acid Energy System Glycogen in LiverCarbohydrate in FoodGlucose in bloodstreamGlucose in MuscleANAEROBICMuscle Sarcoplasm2 ATPGlycolysisPyruvic AcidLactic Acid (1)Lactic Acid (1)+ O2Acetyl Coenzyme A
14Lactic Acid System Advantages ATP can be regenerated quite quickly because few chemical reactions are involved.In the presence of oxygen, lactic acid can be converted back into liver glycogen, or used as a fuel by oxidation into carbon dioxide and water.It can be used for a sprint finish (i.e. to produce an extra burst of energy).
15Lactic Acid System Disadvantages Lactic acid is the by-product! The accumulation of acid in the body denatures enzymes and prevents them increasing the rate at which chemical reactions take place.Only a small amount of energy (5%) can be released from glycogen under anaerobic conditions (as opposed to 95% under aerobic conditions).
16Think long distance running Aerobic Energy SystemStarts similar to the Lactic Acid systemADP + P + Glucose = ATP + Pyruvic AcidAs oxygen is present the pyruvic acid does not convert into lactic acid but into another 34 molecules of ATPLong term low intensity exerciseCarbon dioxide (CO2) and water (H2O0 are waste products of this systemThink long distance running
17Aerobic Energy SystemO2The aerobic system of energy production needs oxygen.Breaks down carbohydrates & fats into CO2, H20 and ENERGYTakes approx 3 mins to extract 95% of energy from glucose moleculeThis supplies the body with a prolonged and steady supply of energy.
18Aerobic Energy SystemImmediate energy production, therefore comes from the other two anaerobic systems used.Heart rate and ventilation rate increase during exercise. The vascular system distributes more oxygenated blood to our working muscles.Within 1-2 mins the muscles are being supplied with enough oxygen to allow effective aerobic respiration
19ATP (1 burst of energy) =ADP ADP+ PCr = ATP (3-10s of work) = ADP ADP + Glucose= ATP (10-60s of work) = ADP + Pyruvic Acid (No oxygen = lactic acid) ADP + P + Glucose = ADP + Pyruvic Acid + Oxygen =34 ATP + CO2 + H20
20Electron Transport Chain 2 ATPMuscle SarcoplasmANAEROBICGlycolysisPyruvic AcidAcetyl CoAO2+ Oxaloacetic AcidMuscle MitochondriaAEROBIC2 ATPCitricAcidKrebs CycleCarbon DioxideHydrogenElectron Transport Chain
22The Aerobic System Advantages More ATP can be produced — 38 ATP from the complete breakdown of one glucose molecule.There are no fatiguing by-products (only carbon dioxide and water).Stores of of glycogen and triglyceride are plentiful, so exercise can last for a long time.
23The Aerobic System Disadvantages This is a complicated system so it cannot be used immediately. It takes time for enough oxygen to become available to meet the demands of the activity and ensure glycogen and fatty acids are completely broken down.Fatty acid transportation to muscles is low and fatty acids require 15% more oxygen to break them down than glycogen.
24Food FuelsFood is the basic form of energy for ATP regeneration. The main energy foods are:carbohydrates — stored as glycogen and converted into glucose during exerciseglycogen — a complex sugar supplied from muscle or liver storesglucose — a simple sugar supplied from the bloodfats — stored as triglycerides in adipose tissue under the skin and converted by the enzyme lipase to free fatty acids when required
25When are These Fuels Used During Exercise? The intensity and duration of exercise play a huge a role in determining whether fats or carbohydrates are used.The breakdown of fats to free fatty acids requires more oxygen than that required to breakdown glycogen. It is also a much slower process.Therefore, during high-intensity exercise when oxygen is in limited supply, glycogen will be the preferred source of energy.