1. EDU2EXP Exercise & Performance 1 Energy Systems

2. EDU2EXP Exercise & Performance 2 Energy systems These are the three energy systems. 1. ATP-PC Energy System (also called Phosphate Energy System, Phospagen system, PC system) 2. Lactic Acid System (also called Anaerobic Glycolysis, Lactacid system) 3. Aerobic System (also called Oxidative system) Anaerobic (ATP generated without oxygen) Aerobic (ATP generated with oxygen)

3. EDU2EXP Exercise & Performance 3 ATP Adenosine Triphosphate

4. EDU2EXP Exercise & Performance 4 Adenosine Diphosphate ADP is ATP minus one phosphate group 14 calories of energy is released each time ATP  ADP

5. EDU2EXP Exercise & Performance 5 Energy Systems ATP-PC Energy System Immediate energy Lactic Acid Energy System Short-term energy Aerobic Energy System Long-term energy All energy systems have to same aim: To create more ATP to produce energy

6. EDU2EXP Exercise & Performance 6 ATP-PC system The simplest of the energy systems Phosphocreatine (PC) is broken down to release energy (facilitated by the enzyme, creatine kinase) This energy is used to add the spare P to ADP to reform ATP Can sustain muscle energy needs for 3 – 15 seconds Cells store ~ 4 – 6 times more PCr than ATP ATP-PC energy system: The first way to re create ATP

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8. 8 Creatine Supplementation Ingestion Creatine monohydrate (20 g per day) over 5 days  increased stores PC Therefore improves performance short intense exercise in non weight bearing exercise Also enhanced physiologic adaptation to resistance training  Increased dynamic muscular strength and muscle mass Beware of side effects  long term still unknown

9. EDU2EXP Exercise & Performance 9 Lactic Acid System-without oxygen Aerobic Energy System-with oxygen Once the ATP PC system is depleted, ATP must be replenished using the other energy systems -> lactic acid and aerobic energy systems these combined form the glycolytic system Glycolytic System This method of ATP production requires the breakdown of glucose in the blood (glycolysis). See overview on next slide

10. EDU2EXP Exercise & Performance 10 Glycogen Glucose Pyruvic Acid Energy ATP ADP + P Energy for muscular contraction No Oxygen Oxygen Present Lactic Acid + Hydrogen ions Krebs Cycle Hydrogen Ions Electron transport Chain ATP for Muscle

11. EDU2EXP Exercise & Performance 11 Lactic Acid System (Anaerobic Glycolysis) During performances of short duration and high intensity that require rapid energy transfer that exceeds that supplied by phosphagens Anything up to 2 minutes Lactate is the by product “Lactic acid system’

12. EDU2EXP Exercise & Performance 12 Lactic Acid System Blood lactate @ rest is usually 1-2 mmol/L but can rise to over 20 mmol/L during intense exertion. Lactate accumulation –rate of lactate production exceeds the rate of lactate removal

13. EDU2EXP Exercise & Performance 13 Lactate Inflexion Point- LIP (lactate threshold) Intensity of exercise above which anaerobic energy system is required to meet energy demands. Measurable as blood lactate levels increase substantially Page 109 of text

14. EDU2EXP Exercise & Performance 14 Aerobic Energy System (Aerobic Glycolysis) The aerobic system has 3 stages responsible for the release of energy, allowing ATP to be resynthesized from ADP (indicated below). Glycogen Glucose Pyruvic Acid Energy ATP ADP + P Energy for muscular contraction Oxygen Present Krebs Cycle Hydrogen Ions Electron transport Chain ATP for Muscle 1 32

15. EDU2EXP Exercise & Performance 15 Krebs Cycle In the presence of oxygen pyruvic acid is converted to a compound called acetyl CoA Acetyl CoA enters the Krebs cycle which is a series of reactions that produces Additional ATP, carbon dioxide and hydrogen Electron Transfer Chain The hydrogen ions released during glycolysis and Krebs cycle are used in chemical reactions. More ATP is produced.

16. EDU2EXP Exercise & Performance 16 Anaerobic/ aerobic systems 12 chemical reactions to convert carbohydrate (either stored glycogen or circulating blood glucose) to pyruvate No Oxygen Pyruvate converted to Lactate Oxygen Pyruvate enters Krebs cycle and is used to generate ATP

17. EDU2EXP Exercise & Performance 17 Transition to Exercise O2 consumption

18. EDU2EXP Exercise & Performance 18 Interplay between Energy Systems

19. EDU2EXP Exercise & Performance 19 Vo2 Max O2 uptake increases with intensity of exercise up until a certain point ml/kg/minute

20. EDU2EXP Exercise & Performance 20 Recovery from exercise Remove lactate Re-oxygenation muscle myoglobin Replace –Muscle glycogen –PC

21. EDU2EXP Exercise & Performance 21 Active recovery Assists with oxidation of lactate (Lactate shuttling) But as is aerobic may impair glycogen synthesis

22. EDU2EXP Exercise & Performance 22 Passive recovery Theory is that this ‘frees’ oxygen for the recovery process Downfall  no lactate shuttling

23. EDU2EXP Exercise & Performance 23 Which is best? Research inconclusive Depends on exercise to recover from Steady rate exercise –PCr stores not depleted –Lactate levels not increased –Depends on post exercise glucose intake Intense/Non-Steady rate exercise –Large O2 deficit

24. EDU2EXP Exercise & Performance 24 Lactate Removal ExerciseRecovery Passive Active Passive

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28. EDU2EXP Exercise & Performance 28 Percentage of energy derived from anaerobic/aerobic sources during selected sports

29. EDU2EXP Exercise & Performance 29 Summary Energy comes from the breakdown of ATP -> ADP The body stores enough ATP for 2 seconds of maximal exercise. Once this runs out -> ATP needs to re-created Done 3 ways 1.ATP-PC Energy system 2.Lactic acid energy system 3.Aerobic energy system