Energy systems Flashcards
(21 cards)
Glycogen sparing
Allows athletes to use fats at higher intensities and more readily at beginning of exercise and throughout.
Results in less use of glycogen earlier in the event meaning that it can be used later when intensities increase
The contribution of each energy system depends on:
- Duration of exercise
- Intensity of exercise
- If oxygen is present
- Depletion of other fuels
The 3 energy systems
ATP-PC system
Aerobic Glycolysis
Anaerobic system
Rate
How quickly ATP is resynthesized
Yield
Total amount of ATP that can be resynthesized from particular energy system
Fatigue
Refers to what inhibits the function of the energy system and forces a reduction in intensity
Intensity
The level of exertion being applied to an activity. Relates to the exercise intensity at which an energy provides the most ATP
Capacity
The ability of an energy system to continue to resynthesise ATP without fatiguing
Finite capacity
means that the energy systems will fatigue rapidly and can no longer produce enough ATP until recovery
Relatively finite capacity
means the energy system can continue to resynthesise ATP for an extended period of time
ATP-PC system characteristics
The ATP-PC system produces energy by breaking down the fuel PC. The chemical reaction does not require oxygen making the ATP-PC system an anaerobic energy system.
The ATP-PC system fuels explosive or maximal intensity actions or movements that are short in duration
ATP-PS system has a finite capacity meaning it will fatigue rapidly and reduce its contribution to ATP re-synthesis
ATP-PS systems fatigues when PC stores are depleted
PC can be replenished and used again during an exercise bout but this is done during periods of rest or low intensity exercise
Used at maximal intensity
Anaerobic Glycolysis System characteristics
- Produces energy through the incomplete breakdown of glucose and pyruvic acid is left as a by product. Without oxygen, pyruvic acid is converted into lactic acid and H+ ions
- It doesn’t require oxygen and occurs when oxygen isn’t available
- Anaerobic glycolysis system is used at very high intensities (85%> max heart rate)
- Due to H+ ion accumulation we will fatigue and be forced to reduce intensity
- Anaerobic system works at a rapid to fast rate however not as rapid as ATP-PC system
- The Anaerobic glycolysis system has a low yield (2-3 ATP) because of fatigue.
- Finite capacity because of fatigue
- H+ ions can be oxidised but this can only happen at periods of rest or low intensity exercise
Aerobic system
- produces energy by break down of fuels glucose and fats
- aerobic system fuels submaximal intensity exercise that are longer in duration
- Aerobic system cannot produce ATP as quickly but we can get alot more ATP from this process
- glucose is broken down completely by using oxygen to produce ATP
- The body’s glycogen stores can last 90-120 minutes. After depletion, fats become dominant fuel. Fats have slower rate and higher oxygen cost than glycogen so intensities must decrease when switching to fats
- Switching from glycogen to fats is a form of fatigue because intensities are reduced greatly
- The A.G. system has a relatively infinite capacity due to high levels of fuel source and non-fatiguing by products associated with the breakdown of fuels
ATP demand
refers to how much ATP is required during an activity and the rate at which it is used and therefore needs to be resynthesized
During an activity, ATP re-synthesis must meet ATP demand of the activity or we will have to reduce intensity of the activity
- ATP demand is dependent on duration and intensity of exercise
- As intensity and duration of activity increases, ATP demand increases
- There is a linear relationship between both intensity and ATP demand and duration and ATP demand
What you should remember all the time
All three energy systems contribute to ATP re-synthesis all the time but their relative contributions will vary based on duration and intensity of exercise.
Interplay of energy systems
- How each system works alongside the other energy systems together
- How much an energy system contributes to ATP re-synthesis will depend on two things: intensity and duration of exercise
Relationship between exercise duration and intensity
- inversely proportional
- as exercise intensity increases, duration decreases (because we fatigue a lot sooner when we increase intensity)
- as exercise duration increases, exercise intensity decreases ( in order for us to exercise for long periods of time, we need to do so at a low intensity- submaximal intensity)
Oxygen Deficit
The period of time where oxygen supply does not meet oxygen demand.
While oxygen deficit continues, the body must obtain ATP from anaerobic systems
Steady state
When oxygen supply meets oxygen demand, the body is said to have reached a steady state
During steady state, the aerobic energy system becomes the major supplier of ATP
Oxygen debt or EPOC
At completion of exercise, the demand for ATP decreases dramatically, however oxygen consumption is still higher than resting levels. This is referred to as EPOC
During EPOC, oxygen supply exceeds demand, the purpose of EPOC is to restore the body back to pre-existing levels
Oxygen consumption and exercise types
Activities that are high intensity and rely heavily on anaerobic systems will have a - large oxygen deficit - a brief or no steady state - a large EPOC Activities performed at low intensities - smaller oxygen deficit - a longer steady state - a smaller EPOC
