Energy systems Flashcards
what food fuel depends on the following 3 things
- oxygen availability
- rate of ATP resynthesis required
- availability of food fuels
what is the glycaemic index
provides an indicator of how quickly glucose is broken down and released into the bloodstream.
What are low GI foods
examples, when it should be consumed
- grain bread, pasta, grains
- release glucose into the bloodstream slowly helping STABILISE BGL during exercise
- gradulally release glycogen throughput even t/s avoiding the depletion of glycogen
- should be consumed before exercise ( 2hrs+) as glucose is slowly released into the bloodstream helping stablise BGL during exercise.
What are high GI foods
examples ,, when should be consumed
- white rice, jube lollies, sport drinks
- release glucose into the bloodstream rapidly increasing BGL
- should be consumed post exercise as they release glucose rapidly into the bloodstream which speeds up recovery as glucose is rapidly transported to the muscle and liver to replenish glycogen lvls t/f can repeat effort sooner
Role of ATP
all muscle contractions result from the energy released during the splitting of the 3rd phosphate molecule
complexity of phosphocreatine
fuel used to resynthesise ATP when the ATP CP system is the most dominant at a very rapid rate. Up to 10 seconds at max intensity. Simple compound
complexity of glycogen
most dominant fuel to resynthesise ATP in the anaerobic glycolysis system.
used at sub-max intensity in the aerobic system to replensih ATP as it requires less o2 to breakdown
complexity of triglycerides
at rest, most domnant fuel used in the aerobic system as it provides the greatest yield of energy ut requires a lot of oxygen to breakdown
the energy system used for resynthesising ATP is determind by…
- Activity intensity
- Activity duration
- the amount and type of recovery
The ATP-CP system
fuel: fueled by stpred ATP as well as phosphocreatine which is stored in the muscle
Duration: up to 10 sec of max effort
Instenisty: 95-100% MHR
Rate: able to resynthesise ATP without the presence of O2 and at a very fast rate, due to the simple chemical pathway
Yield: small 0.7 moL
limiting factor: stored PC are largely depleted after 10 sec- finite capacity
recovery: passive recovery
by-products: fatigue, inorganic phosphate, ADP
typical events: atheletic field events eg shot put and javelin. Sprints eg 100m and 200m
the anaerobic glycolysis system
fuel: muscle stores of glycogen are anaerobically broken down during efforts to release energy of ATP to be resynthesised from ADP
Duration: the AG system operates once CP depletes and until sufficient O2 reches the muscles approx 20 seconds
Instenisty: 85-95%
Rate: fast rate
Yield: 2 moL
limiting factor: production of H+ ions which inhibit muscles ability to contract
recovery: actie recovery
by-products: H+ ions, lactic acid
typical events: 400m sprint
the aerobic system
fuel: as the aerobis system utilises o2 it can use glycogen, triglycerides and if needed protein
Duration: most sig supplier of ATp after 30 sec
Instenisty: 65-85%
Rate: slow/ low b/c of complex chemical pathway
Yield: 36-38 ATP
limiting factor: requires o2, glycogen can be depleted after 90mins so increased use of fats which require a greater amount of o2 to breakdown
recovery: active recovery
by-products: pyruvate which due to the presenceof oxygen, is broken down into heat, water and co2
typical events: rest, walking, 10 km run
pyruvic acid and isufficient O2
id there is insufficient O2 to remove pyruvic acid then it will turn into lactic acid which breaks down into lactate and H+ ions
effect of H+ ions on performance
- increases acidity in muscles
- therefore decreasing its ability to use glycogen
- therefore decreasing the force of muscular contactions
Why cant the AG system produce energy as rapidly as the ATP PC system
AG system has a more complex pathway than the ATP PC system due to the substrate of glycogen taking longer to breakdown as it is a more complex fuel. This means that ATP is resynthesised more slowly and athletes can only perform at intensities of 85-95%
How do you buffer H+ ions and lactate
training in ways like intermediate interval allows the athlete to develop the ability to buffer or tolerate the accumulation of H+ ions and lactate. This means that they can sustain higher intensities for longer
AG system and finite capacity
explain why
the AG system has a finite capacity due to the incomplete breakdown of glycogen leading to a build up of H+ ions
Active recovery
4 steps on what it does
- maintains and elevated heart rate to increase blood flow to muscles
- prevents venous pooling + assists in venous return
- removes fatiguing byproducts
- return to pre-exercise state quicker
passive recovery
doing the same exercise but at a lower intensity
- allows your body to use all of the available oxygen to replenish PC instead of having to use it to contect the muscles hence this is the fastest and best way to replenish PC
what is LIP
- Lactate Inflectional Point
the final intensity that can be maintained before blood lactate producation exceeds removal
Why does fatigue occur beyond LIP?
3 things
- Lactate entry in the blood is greater than lactate removal
- There is a greater contribution from the AG system at intensities beyond LIP
- At intensities beyond LIP the athlete will fatigue decreasing their speed/intensity
Heart rate definition (HR)
number of times the heart beats per minute (bpm)
linear relationship b/w HR and intensity
Stroke volume definition
The amount of blood pumped out of the left ventricle per beat
(mL/beat)
Increases during exercise but plateaus during sub-maximal exercise