St Pauls College Stage 2 Physical Education

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St Pauls CollegeStage 2 Physical Education

• EXERCISE PHYSIOLOGY
• Energy Systems
• Part 5

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ENERGY SYSTEMS

• Energy for muscle contraction comes from the
  breakdown of a chemical compound named Adenosine
  Triphosphate (ATP)
• Splitting of ATP releases energy which stimulates
  the actomyosin
• (Actin and Myosin Sliding Filament Theory)

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ATP
Muscle Contraction
Manufacturing Hormones
Nerve Conduction

• Energy from ATP is used for all functions of the
  body, not just exercise.

Energy from ATP
Building new body tissue
Digestion
Repairing damaged tissue
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ATP Energy
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Fuel Sources of ATP

• We must constantly re-supply or re-synthesize
  ATP.
• Energy for ATP resynthesis comes form the
  breakdown of foods and
• Creatine Phosphate (Exists within the muscles)
• Carbohydrates
• - Break down to glucose and stored as glycogen
  in the muscles and liver
• - Excess carbohydrate intake is stored as
  adipose tissue (fat)
• Fat
• - Broken down to fatty acids and
  triglycerides
• - FA stored as adipose tissue or circulate in
  the blood
• - Triglycerides are stored in the muscles
• Protein
• - Under extreme condition
• - Prolonged starvation
• - End of marathons

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Fuel Sources of ATP
Creatine Phosphate
ATP
ADP P
Lactate
Glycogen (Carbohydrate)
Energy for contraction
Fat
Protein
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Forms of Food Fuel Storage Sites in the Body
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ATP Production at Rest

• ATP is produced in mitochondria and transported
  to myosin cross-bridges.
• While at rest, ATP is produced Aerobically This
  means in the presence of Oxygen.
• It occurs in bean shaped mitochondria found in
  the muscle fibres.
• ATP can be produced without fatiguing
  by-products.
• (CO2 breathed out water sweat, urine, water
  vapor heat).

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ATP Production at Rest
ATP produced here
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Aerobic Energy Production At Rest
Glucose from muscles and liver. Fats
(triglycerides and fatty acids) from blood.
Breathed in
Breathed Out
Lost as water vapour, sweat and urine
Used to combine ADP and Phosphate ADP P ATP
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ATP Production During Exercise

• During exercise the Energy System used to
• produce ATP will depend on
• How long the exercise continues (time).
• How vigorous the exercise is (intensity).
• How well developed the persons
  cardio-respiratory system is (aerobic fitness).
• There are 3 metabolic process that can occur for
  re-synthesizing ATP. These are
• ATP PC System (Phosphagen System) Anaerobic
  No oxygen required
• Anaerobic Glycolysis (Lactic Acid System)
  Anaerobic No oxygen required
• Aerobic System In the presence of oxygen
• The major difference between the three processes
  is the speed with which they can replenish the
  ATP stores.

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Characteristics of the 3 Energy Systems
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Energy Systems Important Information!

• All energy systems work continuously. They do not
  switch on and off light a set of lights.
• The relative contribution of energy from each
  system to a particular physical activity will
  depend on the energy requirements, which will be
  directly related to the intensity and duration of
  the exercise.
• The interplay of the energy systems will vary
  during the course of a sporting activity. For
  example, during a game of Aussie Rules Football
  the full forward will lead for the ball. During
  this lead the Phosphagen System will dominate,
  however, once he finishes his lead and jogs back
  to the goal square the Aerobic system will become
  the dominant supplier of ATP.

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Limitations Advantages of Energy Systems

• ATP-PC System
• Stored ATP and creatine phosphate.
• Are the cash you have in your pocket ie can be
  used immediately.
• High intensity/explosive.
• Only requires one step, therefore is a simple
  pathway, therefore energy available straight
  away.
• Only a certain amount available, therefore only
  10 seconds available.
• 100m sprinter uses basically only phosphagen
  system.
• Oxygen not used.
• Half recovery time 30 seconds 50 recovered.
• After 60 sec 75 recovered.
• After 90 sec 87.5 recovered.
• After 3-4 minutes should be fully recovered.
• System is trainable can improve power output
  and recovery i.e. more stored phosphagen.

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Limitations Advantages of Energy Systems

• Anaerobic Glycolysis
• Fuel substance broken down in steps
• Fuel glucose comes from blood or from stored
  carbohydrate glycogen
• Absence of oxygen
• Lactic acid causes muscular fatigue to the point
  of failure of muscle to contract.

Muscle Glycogen
Glucose
Glycolysis ATP
Pyruvic Acid
Lactic acid (Into blood)
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Muscle Glycogen/Lipids
Conversion to glucose
Pyruvic Acid
With oxygen present
Without Oxygen
Enter Aerobic System (Krebs Cycle)
Build up of Lactic Acid (into blood)
THE AEROBIC SYSTEM
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Limitations Advantages of Energy Systems

• Aerobic System
• Inside mitochondria aerobic respiration (CO2, H2O
  ATP used) occurs.
• Lots of ATP present.
• Pyruvic acid enters mitochondria and is broken
  down.
• Primarily carbohydrates and fats (occasionally
  proteins) are used as energy source. (Only
  carbohydrates used anaerobically)
• Elite v Mr Average
• Elites delivery system for oxygen is better i.e.
  more efficient, thus he will be working
  aerobically sooner
• In hot weather greater of blood sent to skin
  for cooling thus less delivery of oxygen
  therefore anaerobic system takes over earlier and
  results in lactic acid build up.
• High intensity activity transport system cannot
  supply oxygen efficiently enough thus it switches
  to anaerobic pathways.

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Predominant Energy Systems

• ATP-CP
• For an activity of 0-20 seconds at high intensity

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Example of ATP-PC as Predominant System
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Predominant Energy Systems

• Lactic Acid System
• For an activity 20-90 seconds at high intensity

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Example of Lactic Acid System as Predominant
System
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Predominant Energy Systems

• Aerobic System
• For an activity of 90 seconds at moderate
  intensity

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Example of Aerobic System as Predominant System
Hisham El Guerrouj
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Application to Sport

• It is important to remember that all energy
  systems contribute in some way during any
  activity and can change during the course of an
  activity.
• For example, in Soccer, a player will
  predominantly use the ATP-CP system during
  moments of explosiveness, i.e. kicking the ball,
  jumping for a header etc. However the Lactic Acid
  System will be dominant when a player has to
  maintain a sustained run i.e. when sprinting from
  defence to attack and then back into defence. The
  Aerobic System will be dominant when the player
  moves at low intensity and/or when he is
  recovering while the ball is at the other end of
  the pitch.

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Catching his breath Walking Aerobic System
Some poor bloke has just sprinted after him for
about 30 seconds after a goal has been scored!
Lactic Acid System
Explosive shot at goal ATP-CP System