Energy Systems Adenosine Triphosphate (ATP) - PowerPoint Presentation

1. Energy Systems

2. Adenosine Triphosphate (ATP)Our body uses ATP to produce energy.The body transforms the food we eat into ATP.When ATP is broken down it releases ADP + P + energy.The body can resynthesise ATP by the reverse reaction: ADP + P + energy = ATP.The body cannot store much ATP (only enough for about 2-3s of intense activity) so any energy required needs to be produced immediately.

3. Sources of EnergyATP can be resynthesised from the breakdown of carbohydrates (into glucose), fats (into fatty acids and glycerol), and protein (into amino acids).Excess glucose is stored as glycogen in the muscles and liver.Glycerol can be converted into glucose when glycogen stores have been depleted (e.g. marathon).At rest most of our energy comes from fats, during exercise energy is mostly supplied from carbohydrates.

4. Energy SystemsThere are 3 energy systems:The aerobic systemThis is the primary energy system for endurance events. It produces lots of ATP and no fatiguing by-products but it cannot produce energy quickly.The lactate systemThis is the primary energy system for middle distance events. ATP is produced quite quickly but there is a harmful by-product.The ATP-PC systemThis system produces energy extremely quickly but can only fuel around 10 seconds of activity.

5. Aerobic Energy Production from GlucoseWhen oxygen is present glucose can be broken down completely.This occurs in the mitochondria and produces CO2, H2O, and energy (ATP).The advantages of aerobic energy production is that there are no fatiguing by-products, the energy sources are usually abundant and lots of ATP can be produced.The breakdown of glucose into energy (ATP) involves 3 stages: Glycolysis, Kreb’s cycle, and the Electron Transport Chain.

6. GlycolysisThe initial stage of glucose breakdown.This stage is identical in both the aerobic and anaerobic systems.Some complicated reactions take place but the basics you need to know are….Pyruvic acid is produced (pyruvate).2 ATP are used and 4 ATP produced, so there is a net gain of 2 ATP during this stage.As well as ATP we also gain NADH, which becomes important at a later stage (Electron Transport Chain).

7. Kreb’s CycleThis follow’s on from glycolysis, using the products from Glycolysis.It only occurs in the presence of oxygen.The pyruvic acid from glycolysis is added to coenzyme A, producing Acetyl Coenzyme A in preparation for the Kreb’s Cycle.At this stage we gain another NADH for each Acetyl Coenzyme A.Again, lots of complicated reactions take place but all that you need to know is that 2 ATP are produced.In the Krebs cycle we also gain a further 6NADH and 2FADH2

8. Electron Transport ChainThe final stage of glucose breakdown.Once again, numerous complicated chemical reactions take place but all that you need to know is; Large amounts of oxygen are required at this stage (thus it is aerobic energy production).The NADH and FADH2 from previous stages are utilised here.34 ATP molecules are produced.So, at the end of these 3 stages 40 molecules of ATP are produced and 2 are used (net production = 38 ATP).

9. GLYCOLYSIS2ATP are used to split glucose into two 3-carbon molecules.For each of the 3-carbon molecules, 2ATP and 1NADH are produced when forming pyruvic acid.KREBS CYCLEPyruvic acid is not able to enter the Krebs Cycle, so coenzyme A is added to form acetyl coenzymeA.For each acetyl coA that enters the Krebs Cycle 1ATP, 3NADH and 1FADH2 are produced.ELECTRON TRANSPORT CHAINThe NADH and FADH2 molecules produced during Glycolysis and the Krebs Cycle enter the Electron Transport Chain, yielding 34ATP.

10. Aerobic Energy Production from FatFatty acids are broken down by a process called beta-oxidation to acetyl CoA which enters the Kreb’s cycle (and eventually electron transport chain).More ATP can be produced from fat than from glucose (during electron transport chain) but far more O2 is required.Fat is therefore an excellent energy source at rest or low intensity exercise but cannot be used during high intensity exercise when a lack of O2 becomes a limiting factor.

11. Effects of Training on Aerobic Energy SystemsCardiac hypertrophy and increased resting stroke volume (SV).Decreased resting HR.Increased muscle stores of glycogen and triglycerides.Increased capilliarisation of muscle and increased number and size of mitochondria.More efficient transport and effective use of O2 means that fat is used more during exercise (carbs saved for higher intensity). Maximal oxygen consumption (V02 max) increases.

12. Oxygen Consumption (VO2)The amount of oxygen used by our body is called oxygen consumption.During exercise we need more ATP so O2 consumption increases.Often when we begin exercise there is insufficient O2 available to produce ATP aerobically as it takes time for the body to adjust.When 02 consumed is lower than 02 used, there is an ‘oxygen deficit’.O2 consumption increases with exercise intensity until the point of max O2 consumption (VO2 max).

13. VO2 MaxVO2 max is the maximum amount of O2 that the body can consume and use.A higher VO2 max means a higher level of aerobic fitness.If exercise intensity is submaximal (below VO2 max) then O2 consumption reaches a ‘steady state.’ – O2 consumption matches O2 required.VO2 max can be assessed by measuring amount of O2 consumed in comparison to amount of CO2 breathed out during exercise with ever increasing intensity.

14. Factors affecting VO2 MaxVO2 max is the body’s ability to get O2 to the lungs, transfer it to the blood, transport it to muscle cells and mitochondria, and use the O2 in energy processes.It is dependant on:The surface area of alveoli (genetically determined)Red blood cell and haemoglobin levelsThe capillary density in the lungsThe efficiency of the heart and circulatory systemThe capillary density in muscle cellsThe transfer of O2 to mitochondria via myoglobinThe take-up and use of O2 by mitochondria

15. Exam QuestionDescribe the changes that occur in the body to make the aerobic energy systems more efficient following prolonged endurance training. (4 marks)Cardiac hypertrophy – larger heart creates a stronger contraction (pump).Increased resting stroke volume – volume of blood leaving the left ventricle per beat.Decreased resting heart rate – number of beats per minute at rest.Increased blood volume and haemoglobin levels – higher volume of oxygen able to be transported at one time.Increased muscle glycogen stores – greater amount of glucose available for energy production from converted glycogen.Increased myoglobin content in muscles – greater initial receptors of oxygen from the circulatory system before it is transported to the mitochondria.Increased capilliarisation of muscle – more O2 can be diffused into working muscle from circulatory system.Increased number and size of mitochondria – more ATP can be resynthesized in the muscle cell.Resulting increase in VO2 max overall (maximal oxygen consumption).

16. O2 Consumption – Rest & Exercise

17. Post ExerciseFollowing exercise, bodily processes do not immediately return to resting levels, especially after intense exercise.Consuming O2 at higher than resting levels after exercise is called Excess Post-exercise Oxygen Consumption (EPOC). There are 2 components:Fast (alactacid) componentO2 used to resynthesise ATP and phosphocreatine levels, re-saturates myoglobin (which transports O2 from blood to muscle fibres). This component will be very short after highly aerobic exercise.Slow (lactacid) componentO2 used to remove lactate and excess H ions.

18. EPOCDuring the alactacid (fast) component 75% of PC stores are restored within 1min and nearly 100% in 4mins. It takes 2mins to reload myoglobin with oxygen.The removal of lactic acid (slow component) can take up to several hours.As O2 is vital during these processes it is essential to perform a cool down – breathing rate/heart rate is raised slightly above resting level to ensure more oxygen is provided.Fitness levels along with exercise intensity levels determine the duration of EPOC.

19. EIMD & DOMSExercise induced muscle damage (EIMD)Delayed onset of muscle soreness (DOMS) is a symptom of this.EIMD is most severe during different or high intensity training (this is why overload is a key principle of training)One reason these is damage to the sarcomeres (actin/myosin filaments). Protein intake in the 2-hour window of opportunity helps minimise this.Glucose depletion is also a contributing factor so a high carb diet is important.Does muscle soreness mean that training is working?

20. Exam QuestionDuring recovery from exercise, Excess Post-exercise Oxygen Consumption (EPOC) occurs. Explain the differing functions of the fast and the slow components of EPOC, and how EPOC varies with intensity of exercise. (7 marks)Fast component - resynthesis of ATP / PC levels;Alactacid componentResaturation of myoglobin with oxygen75% PC restored within one min, 100% within 4 mins;Slow component - removal of lactate / lactic acid;By oxidation / energy production;Conversion to replenishment of glycogen (glucose) by reconverting lactic acid into pyruvate and continuing through the aerobic processes of Kreb’s cycle and electron transport chain;Some converted to protein / some excreted in sweat and / or urine;Oxygen used to maintain high work rates of heart / breathing muscles;Extra oxygen used as temperature remains high; More recovery time with higher intensities;Greater oxygen consumption with higher intensity;EPOC is larger with higher intensity.

21. At the 2008 Beijing Olympic Games, David Davies won the silver medal in the swimming 10 kilometre marathon event, in a time of 1 hour 51 minutes and 53.1 seconds. Explain how the majority of energy used during the race would be provided. (7 marks)A. Majority produced by the aerobic system/oxygenB. Glycolysis/Anaerobic glycolysisC. Carbohydrates/glycogen/glucoseD. broken down into pyruvate/ pyruvic acidE. Some ATP produced/2 ATPF. Krebs cycleG. Fats/triglycerides/fatty acids/glycerolH. Beta oxidationI. Oxidation of acetyl-coenzyme-A/Citric acid/ production of CO2J. Electron transport chainK. Water/H2O formed/hydrogen ions formed (H+)/ hydrogen/protonsL. Large quantities of ATP produced or resynthesised/34- 36 ATP

22. Figure 4 shows the effects of daily 10-mile runs on the concentration levels of glycogen in muscles.(a) Explain what Figure 4 shows, and briefly explain the role of glycogen in endurance performance. (4 marks)(b) How could elite endurance performers try to artificially increase their glycogen stores in an attempt to improve performance? (2 marks)Exam Question

23. a)Shows that levels of stored glycogen are depleted during 10 mile run;Limited glycogen stores;1 day / 24 hours insufficient time for complete replenishment / equivalent;Lack of glycogen causes fatigue or deterioration in performance; Provides energy (store);For ATP resynthesis;Through oxidation / aerobic;(b) Either –1 Dietary manipulation – (3-4 days) prior to competition ingest no carbohydrates;2 (Day) before competition – high carbohydrate diet, e.g. pasta / carbo loading;Or –3 Exercise plus diet – 4-6 days prior to competition take exhausting run;4 Maintain low carbohydrate diet until day before competition – then carbo load;Or -5 Reduce intensity of training leading up to event;6 Maintain high carbohydrate diet.Mark Scheme

24. Anaerobic Energy SystemsWhen the body is unable to provide the oxygen required to resynthesise ATP it must start to work anaerobically.There are two anaerobic energy systems:Phosphocreatine (PC) energy system (or ATP-PC system)Lactate anaerobic energy systemAnaerobic energy systems

25. Phosphocreatine (PC) Energy System (or ATP-PC system)PC → P + C + Energy AND Energy + P + ADP = ATPFor every molecule of PC broken down, one molecule of ATP can be resynthesised.No oxygen is required.Energy is released very rapidly and there are no waste products.Stores only last for 5-8s of high intensity exercise.It is therefore excellent for very high short intensity activities (e.g. 100m sprint) but not for anything longer.PC can be resynthesised quickly. 50% in 30s, 100% in less than 4 mins (this requires O2 so intensity must be reduced).

26. Lactate Anaerobic Energy SystemThis system involves the partial breakdown of glucose (oxygen is required for full breakdown).2 molecules of ATP are produced for every molecule of glucose (19 times less than aerobic!).Lactate is produced as a by-product.This system can therefore only be sustained for between 10 seconds and 3 mins.Few chemical reactions involved so energy can be produced quickly.summary of anaerobic energy systems

27. LactateHydrogen is released during both glycolysis and the Kreb’s cycle.These H ions combine with oxygen (in the electron transport chain).At some point there becomes too many H ions for the amount of O2 available. Excess H ions combine with pyruvate to form lactate.If high intensity exercise continues then excess H ions continue to build up. This is a contributing factor for fatigue. It produces an acidic environment which slows down enzyme activity and stops the breakdown of glucose. It also effects nerve endings causing some pain.

28. Lactate and Lactic AcidThese terms are often used interchangeably but are actually different things.Lactate is produced by the body during anaerobic exercise. It is not a negative by-product and actually helps to provide the body with energy.Lactic acid is a slightly different substance and isn’t actually produced by the body.That said, you can probably use either term although lactate is technically correct.

29. What happens to Lactate?Lactate is often seen as a ‘waste product’ but can be a useful energy source. During recovery from intense exercise (when O2 is available) lactate can take the following routes:1. conversion to water and carbon dioxide (after being converted back to pyruvate and entering the Kreb’s cycle)2. conversion into glycogen and stored in liver / muscles3. conversion into protein4. conversion into glucose5. conversion into sweat and urine

30. Lactate Threshold / OBLAOnset of blood lactate accumulation (OBLA) is the point at which lactate starts to accumulate in the blood (above 4 mmol per litre).This occurs when there is insufficient O2 available to break down lactate.As exercise intensity increases, O2 consumption increases until VO2 max is reached. Any increase in intensity will then cross the lactate threshold.Predominantly aerobic ATP resynthesis switches to anaerobic when there is insufficient oxygen in the mitochondria to combine with the H released when glucose is broken down.OBLA shows fitness levels as the longer a performer can hold off lactate accumulation, the fitter they are.

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32. 100m SprintingIt is often said that the winner of a 100m race is the person who slows down the least. Is this true?Usain Bolt 100m world record50-60m 0.82 seconds60-70m 0.82 seconds70-80m 0.82 seconds80-90m 0.83 seconds90-100m 0.90 seconds

33. Energy System ContinuumThere are three energy systems that can regenerate ATP:the ATP–PC system (anaerobic) the lactate system (anaerobic) the aerobic systemThe use of each of these systems depends on the intensity and duration of the activity:If the activity is short duration (less than 10 seconds) and high intensity, we use the ATP–PC system. If the activity is longer than 10 seconds and up to 3 minutes at high intensity, we use the lactate systemIf the activity is long duration and submaximal pace, we use the aerobic system.

34. Which energy system?

35. Aerobic or Anaerobic?During nearly all activities both systems will be involved at the same time, the one which is more predominant depends on:The level of intensityThe durationYour level of fitness

36. Energy ContinuumIt is the duration of the activity not the distance covered which determines the energy sources. E.g. Mo Farah can run 3000m in 7.30mins. Another person may take that long to run 1500m. They would both be using a similar percentage of aerobic / anaerobic energy.Distance2004008001500500010000Time22491m533m5514m0030m00% aerobic% anaerobic

37. Think about the tactics involved in races such as 5000m.Mo Farah 5000m last raceThe percentage of aerobic/anaerobic is dependant on how quickly the race is run. E.g. a 200m race could be sprinted anaerobically or jogged aerobically.Distance2004008001500500010000Time22491m533m5514m0030m00% aerobic294366849597% anaerobic7156341653

38. A = ATP-PC SystemB = Lactiate Energy SystemC = Aerobic Energy System

39. FatigueMuscle fatigue is the inability to maintain muscle contractions. There are numerous causes including:An increasingly acidic environment caused by the build up of excess H ions results in a breakdown in chemical reactions.Glucose stores being depleted.A change in the balance of chemicals that instigate muscle contraction.Dehydration causing increased blood viscosity (leading to increased HR, overheating etc.).Damage to muscle fibres (micro tears)

40. Lactate Threshold / VO2 Max and ExerciseWhen an athlete crosses their lactate threshold fatigue will quickly set in.Pacing themselves to work near, but not over, their lactate threshold is key to success in endurance events.As an individual becomes fitter they will be able to work at a higher percentage of their VO2 max (higher intensity) before crossing the lactate threshold (and moving to anaerobic energy systems).The Brownlee Brothers

41. Lactate ToleranceThe ability to withstand the effects of lactate accumulation.This may be related to the amounts of bicarbonate in the blood (which can combine with lactate to reduce its acidity).May just be down to motivation/determination levels.

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43. Energy SystemFuel UsedIntensity / DurationContributionSporting ExamplesATP-PCATPPCHigh / ShortUp to 10s(approx)DivingGym vault100m sprintLactic Acid(Anaerobic Glycolysis)Glycogen / GlucoseHigh IntensityShort – Moderate Duration10s – 3minsDepending on intensity200m sprint400m sprint50m swimAerobic(Glycolysis)CarbohydratesFatsProteins (extreme circumstances)Submaximal ExtendedPeak efficiency achieved in 1-2 mins. Dominant system when HR <85%1500mMarathonTriathlon

44. Exam QuestionMany elite swimmers use blood lactate sampling during training as a means of establishing their training load.(i) What do you understand by the term lactate threshold ? (2 marks)(ii) How is lactate threshold related to VO2 max? (2 marks)(iii) Explain how knowing blood lactate levels during a swim might assist an elite performer. (2 marks)i) 1 Exercise has become anaerobic; 2 Lactic acid accumulates in blood; 3 4 mmol/L of blood.(ii) 1 Lactate threshold is some proportion/percentage of VO2 max; 2 Proportion/percentage increases as fitness increases. (iii) 1 Accurately measures intensity of training; 2 Elite performers need to train close to their Lactate threshold/VO2 max;

45. EXAM QUESTIONSuccessful track and field performance is dependent upon an effective energy supply. Figure 3 shows how the supply of each energy system varies according to the duration of a task.1. Identify each of the energy systems A, B and C. (2 marks)2. Explain how the differing energy sources of these systems are used during:(i) a series of javelin throws; (2 marks)(ii) a long-distance run of increasing intensity. (4 marks)

46. Different Forms of EnergyDiscuss with the person next to you – how many different forms of energy can you name?Mechanical energyElectrical energyPotential energyChemical energyKinetic energy

47. Electrical energy – the energy in electrical chargesPotential energy – the energy possessed by an object because of its positionChemical energy – the energy stored in foodKinetic energy – the energy in moving objects (also called movement energy)Mechanical energy – the sum of potential energy and kinetic energy

48. The hammer has potential energy but no kinetic energy.Lifting the hammer up increases its potential energy.The force applied to the hammer gives it kinetic energy. The sum of the potential and kinetic energy is mechanical energy which is the force applied to the nail.

49. EnergyMessages sent around the body are in the form of electrical energy.When a message travels along a motor neurone it changes to chemical energy as it passes across the synaptic cleft