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PSE 4U Section 5 Energy Systems

PSE 4U Section 5 Energy Systems. Characteristics and Interplay of Energy Systems for Physical Activity. On completion of this topic you should be able to:

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PSE 4U Section 5 Energy Systems

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  1. PSE 4U Section 5 Energy Systems Wayne Judge Sept 2009

  2. Characteristics and Interplay of Energy Systems for Physical Activity • On completion of this topic you should be able to: • Demonstrate knowledge of the characteristics and interplay of energy systems for physical activity and recovery in relation to duration, intensity and type of activity. • Describe the interplay of the energy systems using correct terminology • Analyse the relationship between energy systems and physical activity Sept 2009

  3. ATP - Adenosine Triphosphate • Energy for muscular contraction comes from the breakdown of ATP - adenosine triphosphate. • ATP is a chemical compound which consists of one complex group, adenosine, and 3 less complex parts called phosphate groups Adenosine P P P Sept 2009

  4. Energy From ATP • The bonds between the phosphate groups are high energy bonds. • When one of these bonds is broken energy is released, and ADP (adenosine diphosphate) and inorganic phosphate (Pi) are formed. • The energy released during this breakdown represents the energy used for muscular contraction. Sept 2009

  5. The Breakdown of ATP High energy bonds Energy Adenosine P P P Pi For muscular contraction Sept 2009

  6. ATP – Storage Within Muscles • ATP requirement of a 70kg adult male – 190 kg per 24 hour period Required ATP Store 190 kg Actual ATP Store 50 g Sept 2009

  7. ATP Storage Within Muscles PROBLEM: • There is not enough ATP within our muscles to last for even a few seconds. SOLUTION: • Find ways to replenish our muscular stores of ATP Sept 2009

  8. Production of ATP • Supply of ATP to muscles is dependant upon the resynthesis of ATP from ADP and Pi. • The energy for the resynthesis of ATP is obtained via the three energy pathways or systems. Sept 2009

  9. ENERGY SYSTEMS Anaerobic Aerobic ATP-PC System Anaerobic Glycolysis Aerobic or Oxygen System The Three Energy Pathways (Systems) Sept 2009

  10. The Three Energy Pathways • All three energy systems contribute to the resynthesis of ATP under exercise conditions. • However, which energy system/s is predominate depends upon the ATP demand of the activity. • Two factors determine ATP demand: • Exercise duration – how long the activity lasts for • Exercise intensity – how hard the exercise is performed at • Generally speaking, as exercise duration increases the intensity at which it can be performed decreases Sept 2009

  11. Anaerobic Pathways • Anaerobic pathways can supply energy for ATP resynthesis very quickly. • They are the major energy systems utilised during high intensity exercise since muscles need a rapid but brief supply of ATP during such activities. Sept 2009

  12. Aerobic Pathways • The aerobic energy pathway supplies energy for ATP resynthesis at a much slower rate than the anaerobic pathways. • This system is the predominate supplier of ATP during endurance events: • Slower rate of use • Greater total use Sept 2009

  13. The ATP-PC System Wayne Judge Sept 2009

  14. The ATP-PC System • Least complicated of the three energy systems • Produces energy for ATP resynthesis most rapidly. • Relies upon muscular stores of ATP and another chemical compound called phosphocreatine. P CREATINE Sept 2009

  15. Phosphocreatine • Phosphocreatine (PC), like ATP, is stored in limited quantities in muscles. • Phosphocreatine is also like ATP in that when its phosphate group is removed a large amount of energy is released. • This energy is used to resynthesise ATP from ADP and Pi. P P CREATINE CREATINE + ENERGY + Sept 2009

  16. The ATP-PC System Phospho- creatine ATP Energy Energy Creatine For Muscular Contraction ADP + Pi Sept 2009

  17. The ATP-PC System • PC stores depleted within 5 - 15 seconds of high intensity exercise • Peak energy production from ATP-PC system occurs after approximately 7 – 8 seconds of maximal intensity activity. • Therefore, this system: • Provide only a very limited amount of energy for ATP resynthesis • But is able to supply this energy very rapidly. Sept 2009

  18. The ATP-PC System IN 30 Seconds, List as many sports/events as possible that would primarily use this energy system.

  19. The ATP-PC System and Exercise • This system is the predominant energy system during high-intensity activities: • e.g sprints, throws and jumps • e.g activities that take approximately 5 – 10 seconds to perform. Sept 2009

  20. Textbook Reading Read pages 81 – 83.

  21. The Anaerobic Glycolysis (Lactic Acid) System Wayne Judge Sept 2009

  22. Anaerobic Glycolysis System • Involves muscular stores of glycogen being converted into glucose and then, with the aid of enzymes, this glucose is converted into a substance called pyruvate. • when there is a shortage of oxygen, pyruvate becomes lactic acid. OUCH!! • During this series of reactions, energy is released to resynthesise ATP from ADP and Pi. Wayne Judge Sept 2009

  23. Anaerobic Glycolysis System Glycogen Glucose ATP Energy Energy Pyruvate For Muscular Contraction ADP + Pi Insufficient Oxygen Lactic Acid Pyruvate sufficient Oxygen Wayne Judge Sept 2009

  24. Anaerobic Glycolysis • This system is also activated at the beginning of high intensity exercise. • Predominant contributor of energy for 10 seconds to 2-3 minutes during high-intensity exercise bouts. Sept 2009

  25. The Aerobic or Oxygen System Wayne Judge Sept 2009

  26. The Aerobic System Slowest system to contribute towards ATP resynthesis (takes time for HR and breathing to adjust). However, capable of producing the most energy when comparing all three energy systems. predominate contributor to energy production during continuous sub-maximal exercise which exceeds 2 minutes Sept 2009

  27. The Aerobic System At rest - fats used predominately (⅔’s) and about ⅓ from carbohydrates. enough glycogen (stored glucose) for about 2 hours of prolonged sub-maximal exercise. If you run out of stored glycogen (carbs)  called HITTING the WALL Fat metabolism requires far more oxygen than compared to carbohydrates. Sept 2009

  28. Aerobic Energy Production from Carbohydrates Glycogen is broken down to pyruvic acid and during this process energy is released for ATP resynthesis. In the presence of sufficient oxygen, pyruvic acid enters mitochondria for aerobic energy production Sept 2009

  29. Aerobic Energy Production from Carbohydrates The end products of this process are carbon dioxide (CO2) and water (H2O) Sept 2009

  30. Aerobic System:Carbohydrate Metabolism Stage 1 Glycogen ATP Glucose Energy Energy Acetyl coenzyme A + oxygen For Muscular Contraction ADP + Pi Stage 2 ATP Krebs Cycle Energy Energy Stage 3 Energy ET Chain ADP + Pi

  31. ATP Production Under Exercise Conditions For activities of high intensity and short duration: Anaerobic pathways supply the great majority of the energy required. Activities of a prolonged sub-maximal or low-intensity nature: Aerobic system supplies the bulk of the required energy once the respiratory and circulatory systems have adapted to meet the muscles demand for extra oxygen for the aerobic resynthesis of ATP. Sept 2009

  32. Energy Systems Interplay Most activities rely on a combination or interplay of the energy systems, with all three energy systems contributing to the total energy supply. Body does not suddenly switch from one energy system to another. Transition - one energy system is increasing its contribution while another, is decreasing its relative contribution. This can be best illustrated by considering what happens when we undertake a high intensity activity. Sept 2009

  33. Energy System Contributions to High Intensity Exercise Aerobic System: If the exercise continues beyond about 45 seconds, the intensity must decrease in order for it to be continued. If the exercise continues for 1-2 minutes or longer the aerobic system will become the predominant energy supplier. This can be shown on the following graph: Sept 2009

  34. Wayne Judge Sept 2009

  35. Energy System Contributions During High Intensity Activity ATP-PC system: Predominant energy system during the first 5 - 10 seconds. Anaerobic glycolysis system: If the exercise continues beyond 15 seconds this system will begin to assume predominance. It will be the predominant energy supplier for high intensity activities of 30 – 60 seconds duration. Sept 2009

  36. Wayne Judge Sept 2009

  37. Textbook Reading Read pages 84 – 85 Add Table 5.1 on page 86 to your notes

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