Energy continuum

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  • Created by: claud
  • Created on: 03-11-14 17:32

Which system for which activity?

Examples from hockey

  • sprint to receive ball.........ATP/PC system
  • long run to offer support......Lactic acid system
  • jogging onto pitch.............Aerobic system

**The relative contribution of each system depends on the duration and intensity of exercise**

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Definitions

THRESHOLD

  • POINT AT WHICH SYSTEM CAN NO LONGER SUPPLY ENERGY

OBLA

  • ONSET OF BLOOD LACTATE ACCUMULATION
  • POINT WHERE THERE'S A RAPID INCREASE IN AMOUNT OF LACTIC ACID IN BLOOD
  • AT THIS POINT BLOOD PH DECREASES 
  • MUSCLE FATIGUE OCCURS
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Factors affecting the energy systems

Factors affecting energy systems

  • fitness level
  • exercise intensity and duration
  • energy system threshold
  • O2 transport and supply
  • food / fuel available
  • enzyme activation levels
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Intensity and duration of exercise

Intensity and duration of exercise

  • combination of intensity and duration decides energy system
  • anaerobic exercise intensity = ATP/PC and LA systems
  • aerobic exercise intensity = aerobic system
  • during high intensity exercise lactate accumulates
  • when lactate accumulates above resting levels it is called the lactate threshold
  • OBLA is when blood lactate levels exceed 4mmol/L
  • this causes muscle fatigue
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Energy system thresholds

Energy system thresholds

  • threshold is point at which one energy system is taken over by another
  • shows potential duration a system can perform for
  • threshold alters in response to intensity and duration
  • threshold doesn't always follow the same route
  • in team games, players continually switch between energy systems
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Oxygen availability

Oxygen availability

  • availability dependent upon efficiency of respiratory and cardiovascular systems
  • affects which food fuels can be broken down to resynthesise ATP
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Fuel availability

Fuel availability

  • PC stores are limited
  • PC can be conserved by pacing and resynthesising during periods of recovery
  • Glycogen readily available in muscles, requires little oxygen so breaks FFAs down quickly
  • The greater the liver / muscle glycogen stores, then the longer the performer can work aerobically at a higher intensity
  • High intensity short duration activity = breaks down glycogen as energy fuel
  • Low intensity long duration activity = breaks down FFAs and glycogen as energy fuel
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Enzyme activation level

Enzyme activation level

  • enzymes are catalysts
  • without enzymes there'd be no reactions and no energy for ATP resynthesis

Increase in ADP, decrease in ATP > creatine kinase released > PC system

Decrease in PC > PFK released > LA system

Increase in adrenalin, decrease in insulin > PFK released > Aerobic system

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Fitness level

Fitness level

  • the more aerobically fit the performer is, the more efficient their respiratory and cardiovascular systems are
  • an aerobically trained athlete reaches OBLA later
  • an anaerobically trained athlete has increased thresholds of ATP/PC and LA systems
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