Energy Systems

1
Energy Systems

• 3 Systems
• 3 groups of energy nutrients
• Muscle fibre types

2
Three Energy Systems

• ATP PC (anaerobic alactic) No oxygen
• Glycolysis (anaerobic lactic) No oxygen
• Aerobic System oxygen needed

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Adenosine Triphosphate (ATP)

• ATP It is re-synthesized in two ways
• Aerobically in the mitochondria 36 ATP
• or
• Anaerobically in the cytoplasm 1or 2ATP
• 1 molecule of PC gives 1 molecule of ATP
• 1 molecule of glucose gives 2 ATP Lactate

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The Three Energy Nutrients

• Carbohydrates glucose and glycogen
• Proteins amino acids
• Fats fatty acids

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ATP PC system

• Anaerobic alactic no lactic acid is produced
• Lasts 10 -15 seconds
• Uses stored ATP and creatine phosphate
• No by-products, just the product ATP

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Glycolysis

• Anaerobic Lactic system
• Lasts 15 seconds 3 minutes
• Uses glucose and glycogen to make ATP
• By product is lactic acid

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Aerobic System

• Occurs in cytoplasm and mitochondria
• Needs oxygen to produce all 36 ATP
• Lasts as long as you are alive
• Uses glucose, glycogen, fats, and proteins to
  make ATP
• By-products are carbon dioxide and water

8
Muscle Fibre types

• Type I slow twitch (aerobic)
• Type IIA Fast twitch ( Fast twitch oxidative or
  FOG)
• Type IIB Fast twitch (anaerobic)

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Type I

• Slow contractions but can go a long time
• Red (dark) in colour
• Predominantly used in aerobic activities
• High concentration of myoglobin muscle can
  store oxygen for regeneration of ATP

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Type II A

• In between fast and slow twitch
• Faster, stronger contraction than Type I but can
  be sustained longer than Type IIB
• Redish/white in colour
• Moderate myoglobin concentration
• Predominantly used in anaerobic activities

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Type II B

• Fast twitch
• White in colour
• Fastest contraction speed of all muscle fibres
• Low myoglobin concentrations
• Predominantly used in anaerobic alactic
  activities explosive lift or jump

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Approximate Distribution of muscle fibre types
Sport slow twitch fast twitch
Cycling 61 39
Middle distance runner 59 41
Sprinter 26 74
Untrained person 42 58