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
Cardiac output definition
The amount of blood pumped out of the left ventricle per min.(L/min)
Q = SV x HR
Acute cardiovascular responses
9 of them
- increased systolic BP
- increased HR, SV and Q
- Redistribution of blood to working muscles
- increased VO2
- decrease in blood plasma volume
- increased venous return
systolic and diasolic BP
in systolic its the pressure measured on the artery wall during contraction and diastolic during relaxation. (mm HG)
what is AVO2 difference
the difference between the concentration of oxygen in the arteries and the concentration of oxygen in the veins.
VO2 definition
the amount ofoxygen that can be taken in, transported and used by the working muscles.
VO2 = Q x a-VO2 diff.
Acute respiratory responses
- increased RR, TV and V
- increased alveolar capillary diffusion
- increased pulmonary diffusion
increased pulmonary diffusion (gaseous exchange)
during physical activity diffusion capacity @ alveoli/capillary and muscle/capillary is increased to allow greater amounts of o2 and co2 to be exchanged at these sites.
increased respiratory rate and definition
- number of breaths taken per minute
- under high intensity exercise RR ^ due to increased demand for o2 and the removal of co2
increased tidal volume definition
- amount of air breathed in and out per breath (litres/breath)
- increase at maximal workloads in order to supply more o2 to the blood to deliver to the working muscles. plateaus at sub max intesity
increased VO2
o2 uptake increases as a result of increased V due to greater demand for o2 by the muscle. Will not increase further once max levels are achieved. Follows same path as HR
increased Ventilation and definition
V=RRxTV
The amount of air breathed in and out per minute (litres/min)
due to increased RR and TV, V will also increase, any increase non linearly after sub max intensity is due to RR (H+ ions and co2)
Mechanism for Ventilation
when we begin to exercise receptors in the muscles stimulate an increase in Ventilation. This increase in respiration is triggered by an increase in co2 and H+ levels in the blood. The entire process is controlled by the respiratory control system in the brain.
Mechanism for increased diffusion
increased need to deliver o2 to the muscles and remove co2 and metabolites at increased intensities. (alveoli capillary surface area increases with increased tidal volume)
Acute muscular responses
- increased motor unit recruitment
- increased muscle temperature
- increased AVO2 difference
- depleted energy stores (ATP, PC, glycogen and triglycerides)
- increased enzyme activity
- increased lactate levels
EPOC definition
during this period, the body is taking in and transporting more oxygen than required at low intensities as it is trying to return the body to pre-exercise state.
Responses during EPOC
- increased Q, HR+SV
- increased VE, RR+TV
- increased muscle enzyme activity
- increased core temperature
- decreased fuels
first 3 mins in EPOC
- PC is restored
- 2-3 seconds of stored ATP is restored
- restore o2 to myoglobin
3 mins to hours in EPOC
- removal of metabolites (2hrs+)
- core temperature
- HR and VE
Factors determining how long someone will be in EPOC
- greater the contribution from anaerobic systems, the longer in EPOC
- an active recovery means longer in EPOC H/W it will remove metabolites at a fatser rate
increased Heart Rate
cardiovascular
- heart arte increases in order to supply the muscles with more blood and oxygen
- increases linearly
- as HR ^ so does exercise intensity
- will increase until the oxygen demands of the activity have been met
increased Stroke Volume (SV)
cardiovascular
- stroke volume increases with exercise intensity but plateaus at sub max intensity thus less room for increase
- will remain unchanged until exhaustion
- trained athletes have a larger left ventricle t/f ^ SV
increased cardiac output (Q)
cardiovascular
- increases due to an increase in both HR and SV
- any increase after sub max intensity is due to HR as SV plateaus
- delivers more blood and o2 to the working muscles
Increased systolic blood pressure
cardiovascular
- during exercise systolic blood pressure increaes due to increased HR,SV and Q. diastolic BP remains largely unchanged
- resistance training results in greater increase in BP
mechanism for increased blood pressure
cardiovascular
as exercise intensity increases so does cardiac output and t/f blood pressure increases. Arteries will vasodilate to enable greater volume of blood to be delivered at a faster rate
vasoconstriction definition
decrease in diameter of blood vessels t/f decrease in blood flow
vasodilation definition
increase in diameter of blood vessels t/f increase in blood flow
redistribution of blood flow to working muscles
- during exercise, blood flow is redistributed to the working muscles and away from areas that are less needed eg kidney and liver. Redistribution is achieved by capillaries expanding to the working muscles (vasodilation) and constricting to organs (vasoconstriction)
acute muscular responses
- increased motor unit and muscle fibre recruitment
- increased blood flow to muscles
- increased AVO2 diff
- increased muscle temp
- increased muscle enzyme activity
- decreased muscle substrates (fuels)
Increased motor unit and muscle fibre recruitment
when exercise begins, an increase in motor unit recruitment must take place so that more muscle fibres are activated to contract at higher intensities
increased blood flow to the muscles
at increased intensity there is greater blood flow directed to the working muscles which is achieved via vasodilation to capillaries surrounding the muscle and redistributing blood flow from non essential organs to working muscles ^ O2 delivery
increased AVO2 difference
the differnece between o2 levels in blood in the artery compared to the vein. ABO2 diff is larger during exercise as the muscle consumes more o2
increased muscle temp
the resynthesis of ATP aerobically results in increased muscle and core temp. Metabolic activity increases core and muscle temp
Increased muscle enzyme activity
oxidative enzymes: assist in metabolising triglycerides and glycogen within the muscle, speeding up ATP resynthesis aerobically
**Glycolyic enzymes: **spped up rate that glycogen in broken down via the AG system speeding up ATP resynthesis via AG sytsem
ATPase
Creatine Kinase
decreased muscle substrates (fuels)
max intensity- ATP PC
sub max - glycogen
rest - triclycerides
relative VO2 max
if two individuals have the same absolute VO2 max. the athlete that is lighter will have higher relavtive VO2 max. enables comparisons b/w athletes
factors affecting mac o2 uptake
body size: heavier person requires more 02 than smaller
Gender: females= lower blood volume, smaller lung volue and left ventricle, more fat and less muscle
Genetics: o2 uptake varies due to genetics
Age: max O2 uptake declies with age
