Energy Systems

• Adenosine Triphosphate 


  The only usable form of chemical energy in the body

  Gained from broken down food which releases energy to form it
• ATPase 


  The enzyme which is used to break down ATP

  Creates Adenosine Diphosphate, phosphate and energy
• Phosphocreatine 


  Found in the muscles

  Often used to fuel chemical reactions
• ATP-PC System 


  Used for maximal intensity exercise

  Can only be replenished or resynthesized in a low-intensity environment when

  Can only be replenished in the presence of oxygen
• ATP-PC System (Molecular Level)


  Fuelled by Phosphocreatine

  Reaction occurs in the sarcoplasm of the muscle

  Uses the enzyme creatine kinase

  Yield of 1:1 without by products
• Examples of ATP-PC sports 


  100m sprint

  Long jump

  50m swimming
• Advantages of ATP-PC System 


  Quick process

  Phosphocreatine stores can be quickly resynthesized (30 seconds - 3 minutes)

  No harmful waste products

  Creatine supplements can extent the process
• Disadvantages of ATP-PC System 


  Limited supply of Phosphocreatine to muscles

  Only yields 1 molecule of ATP for one molecule of Phosphocreatine

  Can only be resynthesized in the presence of oxygen
• Anaerobic Glycolytic System 


  Provides energy in high-intensity situations for longer than the ATP-PC system

  Length of use depends on natural fitness levels

  Gains fuel from breakdown of glycogen into glucose
• Anaerobic Glycolytic System Pathway


  Glycogen is broken down into glucose from glycogen phosphorylase

  Glucose breakdown by phosphofructokinase with glycolysis forms 2 ATP molecules

  The process forms Pyruvic Acid which is broken down to form lactic acid through lactate dehydrogenase
• Anaerobic Glycolytic System (Molecular Level)


  Fuelled by muscle or liver glycogen

  Reaction occurs in the sarcoplasm of the muscle

  Uses the enzymes of: glycogen phosphorylase, phosphofructokinase and lactate dehydrogenase

  Yield of 1 Glycogen to 2 ATP

  Produces Lactic Acid as a waste product
• Advantages of Anaerobic Glycolytic 


  ATP can be quickly regenerated

  Lactic Acid can be removed in the presence of oxygen

  Offers the opportunity for an extra burst of energy
• Disadvantages of Anaerobic Glycolytic 


  Lactic Acid is a harmful by-product

  Only small amount of energy released from glycogen in anaerobic conditions
• Examples of Anaerobic Glycolytic sports 


  Velodrome cycling

  400m sprint

  Basketball (Team sports in general)
• Aerobic System 


  Occurs when at a low level of intensity and a high level of oxygen is present

  Split into: Glycolysis, Krebs Cycle and Electron Transport Chain

  Can produce up to 38 ATP molecules
• Glycolysis (Aerobic System)


  Occurs in the sarcoplasm of the muscle cell

  The breakdown of glucose to pyruvic acid in the presence of oxygen

  2 ATP molecules are resynthesized
• Krebs Cycle (Aerobic System)

  Acetyl-coenzyme A diffuses into the mitochondria

  Mixes with oxaloacetic acid to form citric acid

  Citric acid is broken down to release carbon and hydrogen

  The carbon forms carbon dioxide and is breathed out while hydrogen goes to the Electron Transport Chain

  2 ATP molecules are produced
• Electron Transport Chain (Aerobic System)


  Occurs in the mitochondria

  The Krebs cycle hydrogen is moved by hydrogen carriers to the Electron Transport Chain

  Hydrogen splits into hydrogen ions and electrons

  The process produces 34 ATP molecules
• Beta Oxidation 


  Stored fats are broken down into glycerol and three fatty acids

  The fat is transported by the blood into the muscle cell

  Converted to Acetyl-coenzyme A by beta oxidation which enters the Krebs Cycle
• Advantages to Beta Oxidisation 


  More ATP is produced per molecule of fatty acid than molecule of glucose

  Good at long durations and low intensity

  Fatty acids are the main source and help lose stores of fat
• Disadvantage of Beta Oxidation 


  Depends on the fitness levels of the performer
• Advantages of Aerobic System 


  38 ATP molecules are produced

  No fatiguing by-products and only CO2 and water is produced

  Lots of natural glycogen stores mean exercise can last a long duration
• Disadvantages of Aerobic System 


  Highly complicated system

  Oxygen availability needed to meet the demands of activity

  Glycogen and fatty acids must be broken down

  Fatty acid transportation is low which means 15% more oxygen is required to be broken down
• Examples of Aerobic System sports


  Marathon running

  Tour de France (predominantly)

  Long distance / endurance swimming
• Energy Continuum's


  One type of energy system is the predominant energy provider

  Determined by the intensity and duration of the activity
• Energy Threshold


  The point at which an athlete moves from one energy store to another
• ATP-PC / Anaerobic Glycolytic Threshold 


  10 seconds
• Anaerobic Glycolytic / Aerobic Threshold 


  3 minutes
• ATP Generation in Slow Twitch Fibres 


  Main pathway occurs in the aerobic system

  Produces the maximum amount of ATP from each glucose molecule

  Production is slow but fibres are endurance based so don't fatigue
• ATP Generation in Fast Twitch Fibres 


  ATP production in the absence of oxygen is not efficient as only produces 2 ATP molecules per glucose

  Main pathway for ATP production is through glycolysis

  Production of ATP is fast but unable to last as they fatigue quickly
• Fats VS Carbs for ATP


  Fat usage becomes limited at intensity

  More oxygen than glucose is required in the breakdown

  Continued exercise sees the need for fat as energy drop
• Oxygen Consumption During Exercise 


  Oxygen Consumption = amount of oxygen needed to produce ATP

  Referred to as VO2 Max

  Consume an average of 0.3 to 0.4 litres of oxygen per minute
• VO2 Max


  Maximum volume of oxygen that can be taken up by the muscles per minute
• Sub-Maximal Deficit 


  Energy is provided anaerobically to satisfy the increase in demand for energy until the body is able to cope
• Maximum Oxygen Deficit 


  Gives an indication of anaerobic capacity

  Bigger during maximal exercise as they have to work anaerobically
• Oxygen Consumption during Recovery


  Involves returning the body to its pre-existing levels

  Oxygen consumption remains high when compared to rest

  Depends on duration and intensity of exercise
• Excess Post-Oxygen Consumption


  The extra amount of oxygen consumed during recovery compared to rest
• Fast Component (EPOC)


  Known as the alactacid component

  Complete restoration takes up to 3 minutes

  50% of stores take 30 seconds

  Oxygen stores in the myoglobin are limited
• Removal of Lactic Acid (EPOC)

  Pyruvic Acid to enter Krebs Cycle = 65%

  Transported into the liver to convert blood glucose = 25%

  Converted into protein = 10%

  Removed in sweat and urine = Minor Amount
• Maintenance of Breathing and Heart Rates 


  Extra oxygen is required to fuel the demands of the muscles

  Aims to restore the body to a level of rest or pre-existing state