Muscle Fibres & Energy Systems Flashcards
What are the 3 types of muscle fibres
Type 1 - Slow oxidative
Type 2 a - Fast oxidative glycolytic
Type 2b - Fast twitch glycolytic
Whats genetically determined when talking about skeletal muscles + the 3 fibres?
What does this mean?
The proportion of these different fibre types
Means some people are born with a natural ability to be better at some sporting activities than others.
What type of fibres do 800m runners and 400m swimmers tend to have?
Type 2 a - fast oxidative glycolytic
What type of fibres do elite power athletes like 100m sprinters or weightlifters tend to have?
Type 2b - Fast twitch glycolytic
What type of muscle fibres to games players tend to have?
An even mixture
What determines what type of fibre a fibre is?
Structural + funcitonal characteristics
What are the structural + functional characteristics (7)
Contraction speed
Fatigue resistance
Mitochondrial density
Myoglobin content
Capillary density
Aerobic capacity
Anaerobic capacity
Fatigue resistance for the fibre types
Type 1 - V high
Type 2a - Medium
Type 2b - Low
Mitochondrial density for the fibre types
Type 1 - High
Type 2a - Medium
Type 2b - Low
Myoglobin content for the fibre types
Type 1 - High (red)
Type 2a - Medium (red)
Type 2b - Low (red)
Capillary density for the fibre types
Type 1 - High
Type 2a - Medium
Type 2b - Low
Aerobic capacity for the fibre types
Type 1 - High
Type 2a - Medium
Type 2b - Low
Anaerobic capacity for the fibre types
Type 1 - Low
Type 2a - Medium
Type 2b - High
Force produced for fibre types
Type 1 - Low
Type 2a - high
Type 2b - v high
How much can training cause physiological adaptations in muscle fibres?
10-20%
What does regular exercise, following the principles of training increase?
Size and strength of all fibre types
== hypertrophy
What are type 2a fibres able to do depending on duration and intensity of training?
Take on characteristics of either type 1 or type 2b
Why does the body need energy? (5)
Muscular contractions + movements
Circulation of blood
Transmission of impulses
Digestion of food
Replacing + repairing tissue
What does it mean that ATP is exhausted within a few seconds?
Needs to be constantly resynthesised in order to provide a continuous supply of energy
What type of compound is ATP
High energy
What are the 3 energy systems in the body that can be used to provide energy for the resynthesis of ATP?
ATP-PC System (Anaerobic)
Lactic acid system (Anaerobic)
Aerobic system
What happens in the ATP-PC system
Quickest energy supply so works first
System lasts until PC stores have run out (8-10secs)
What activities is the ATP-PC system used for
High intensity
i.e 100m sprint, smash shot in tennis
Equations for the ATP-PC energy system
ATP —(ATPase)—- ADP + P + ENERGY
PC —(creatine kinase)—- P + C + ENERGY
ENERGY + ADP + P —– ATP
4 advantages to ATP-PC Energy system
Rapid energy release
No O2 required
No waste product
Creatin stored w/in the muscles
disadvantages to ATP-PC energy systems
PC stores are limited (8-10secs)
Can take up to 3 mins to fully replenish PC stores
When is the Lactic acid/glycolytic system used?
When stores of ATP + PC have run out + body still needs to provide energy quickly
Intense exercise lasting around 1-3mins
Explain the Lactic acid/glycolytic system
Relies upon the breakdown of glycogen through anaerobic glycolysis
Advantages to Lactic acid/glycolytic system
Quick
Reactions take place w/in sarcoplasm of muscle - less distance to sink
Greater energy yield than ATP-PC system as 2 molecules of ATP are produced for each molecule of glucose broken down
Disadvantages to Lactic acid/glycolytic system
Only carbs in the form of glycogen can be used - NOT fat
Glycogen stores are limited
Lactic acid (by-product) causes fatigue
What are the 3 sections the aerobic system are broken down into
Aerobic glycolysis
Kreb’s cycle
Electron transport system
Explain aerobic glycolysis
Glucose/Glycogen
Glucose Phosphate
Fructose Bisphosphate
TPx2
Pyruvate x2
Where does aerobic glycolysis take place?
In the sarcoplasm inside muscle cell
Explain the Kreb’s cycle
AcCoA + Oxaloacetate (4C) compound — Citrate (6C)
(Dehydrogenation + Decarboxylation occur)
(5C) compound
(Dehydrogenation + Decarboxylation occur)
(4C) compound
(Substrate-level phosphorylation)
(4C) compound
(Dehydrogenation with FAD)
(4C) compound
(Dehydrogenation)
Oxaloacetate (4C)
Where does the Kreb’s cycle take place
Within the matrix of the mitochondria
Explain the electron transport system
Red. NAD is oxidised at 1st P pump by losing 2H. Then split – 2e- + 2H+.
High energy e- fuel the 1st P pump to pump 2H+ from MATRIX — IM space.
2 e- then passed to mobile e- carrier in membrane which takes e-‘s to 2nd P pump. Energy is used to pump 2 P across membrane into IM Space.
Repeat stage 3 at 3rd P pump.
2e-‘s then passed to O2 (final e- acceptor) to combine w. 2H+ —- H20.
==== P Pumps create a P gradient between IM space + matrix. == P diff ⬇️ conc. grad. through ATPsynthase. Energy released is used to ADP+Pi– ATP
Advantages to the aerobic system
19 times more efficient than anaerobic as a total of 38 ATP molecules are produced.
CO2 + H2O byproducts are easily removed from body compared to lactic acid.
Can use fat OR carbohydrates
Disadvantages to the aerobic system
Requires large amounts of O2
Complex chain reactions take longer to initiate
What does the predominant energy system used to re-synthesis ATP depend on?
Intensity
Duration
Fitness level
Predominant energy systems used to re-synthesis ATP
Explain intensity
More intense = more anaerobic energy be used (PC + muscle glycogen)
Low to medium = Aerobic system
Predominant energy systems used to re-synthesis ATP
Explain duration
High intensity + over 2 mins = PC and muscle glycogen will become depleted + need repaying.
Intensity of exercise will drop as aerobic system becomes more dominant
Predominant energy systems used to re-synthesis ATP
Explain fitness level
Higher level of aerobic fitness = longer time to reach anaerobic threshold.
Trained performer will have a higher point of OBLA and lactate threshold.
Why is it beneficial to have a higher level of aerobic fitness?
Because as soon as performer works anaerobically there is only a limited supply of energy available.
Define threshold
Point at which the predominant energy system can’t provide sufficient ATP to maintain the current intensity of exercise.
What determines the % of VO2 max a performer can. use?
The OBLA
What can an untrained person work at of their VO2 Max w/out fatiguing?
55-60%
Endurance training can ⬆️ this to 70-80%
Explain the energy continue, during a 1500m race
Use of each energy system is determined by intensity + duration.
START = ATP-PC system as there’s a high intensity sprint off the line to gain position. - Limited to 10 secs so…
Anaerobic glycolysis used for 1st 100-150m. - Limited supply of muscle glycogen + build up of lactic acid means intensity has to drop.
Pace settles using aerobic system as you’re working at a lower intensity for high duration. Working under anaerobic threshold 60-80%
Towards end intensity ⬆️ so more anaerobic systems used.
FINAL sprint = PURE ATP-PC
