Rapid Energy Production And Muscle Metabolic Fathue Flashcards
How many grams of ATP is stored in muscle tissue
40-50g
How quickly is ATP stored in muscle used up
2-4 seconds
What are the 4 main ways of generating ATP
Creating phosphate, anaerobic glycolysis, aerobic glycolysis, aerobic lipolysis
In what order do we use ATP during exercise
ATP stores first, creating phosphate, anaerobic glycolysis, aerobic glycolysis and finally aerobic lipolysis
Why can we not rely on aerobic metabolic pathways for energy during high intensity short duration exercise
The rapid demand in ATP means there is not enough time to rely on aerobic metabolic pathways for energy e.g., oxygen to be delivered and utilized by the muscle; TOO SLOW!
What is the creative phosphate pathway
Creatinephoshpate is a molecule containing creatine and a phosphate group. When there is a very rapid increase in energy demand. For example when you suddenly start sprinting and ATP is used up quickly, Creatine Phosphate will split into creatine and phosphate, and this phosphate group can now be used to build generate new ATP that can then be used again for energy production.
How does the phosphocreatine system synthesise ATP
The breakdown of ATP to ADP activates creatine kinase, the enzyme that catalyses the breakdown of phosphocreatine to creating and phosphate to synthesise more ATP
What enzyme catalyses the breakdown of phosphocreatine
Creatine kinase
What activates creatine kinase
ATP breakdown
How much PCr do we store in the muscle
120g
Why is PCr unsustainable
Eventually as exercise duration continues, production of ATP through this method is unsustainable. This is due to an increase in ATP from other energy sources and a reduction in ADP which will inhibit the activity of creatine kinase, influencing this reaction as creatine kinase is the key regulator of PCr breakdown.
What is meant by anaerobic alactic
Neither produces lactic acid nor does it require oxygen
How many seconds of exercise can PCr fuel
10-14 seconds of exercise
Can PCr concentration in the body reach zero/run out
No- PCr concentrations never reach 0, your body has a fail safe mechanism to avoid this!
Where does the energy come from to restore phosphocreatine
Aerobic energy production, which happens at a much slower rate
What is the rate of PCr resynthesis
We can fully resynthesize PCr pretty quickly (within 3-5 minutes)
What happens when blood flow (oxygen delivery) is blocked
PCR resynthesis is inhibited as requires oxygen
Why is Excess post-exercise oxygen consumption (EPOC) important
Rapid need for energy creates an oxygen deficit, during the oxygen deficit energy comes from anaerobic glycolysis and PCr, EPOC restores PCr via heavy breathing post exercise
How can we manipulate PCr stores in the body
Creatine supplement - Taking creatine increases intramuscular stores, theoretically, this should improve performance because these stores wont be depleted so quickly
What is glycolysis
This is the metabolic pathway that we use to turn glucose (e.g., sugar) into energy
It can be used to generate energy without the need for oxygen (anaerobic)
What is the aerobic contribution during 10 seconds of exercise
Very small (3%)
What is the aerobic contribution during 30 seconds of exercise
Small (15%)
What is the aerobic contribution during 60-90 seconds of exercise
Just over half (55%)
What is the aerobic contribution during 90+ seconds of exercise
2/3 (70%)
What pathways are required during high intensity intermittent exercise
Both anaerobic and aerobic sources
However, because of the longer duration, there will be a large contribution from aerobic sources. Mostly derived from carbohydrates but also fats too.
What happens to anaerobic glycolysis contribution during exercise
After as little as 4 or 5 all out 6 second sprints the contribution from anaerobic glycolysis begins to fall
How long is needed to resynthesise PCr
3-5 minute recovery
What is the biggest limit of recovery
Glycolysis
Why can you not keep sprinting at the same intensity
intramuscular glycogen stores are depleted after high intensity intermittent exercise
So this means the contribution from aerobic sources must increase during intermittent sprint exercise
This is why you cant keep sprinting at the same intensities – aerobic metabolism just isn’t quick enough
How do we fatigue during HII sports
Running list of muscle glycogen, 50% of all muscle fibres depleted of glycogen
What can decreased glycogen impair
Ca2+ uptake in muscle (affects muscle contraction)
What is Acidosis
Reduced pH (affects enzyme activity)
What is sodium-potassium dysfunction
HIE increases potassium efflux into the extracellular space – can decrease muscle force
What is PCr depletion
We only have a finite store, hence why people often supplement with creatine
What are reactive oxygen species
molecules that have an unpaired electron – damage other cells by stealing electrons
What are the effects of metabolic fatigue during high intensity intermittent sports
Acidosis, impaired Ca2+ function, H+ build up, Reactive oxygen species, increase in extracellular potassium, muscle glycogen depletion and PCr depletion
Why is metabolic fatigue in high intensity intermittent exercise complex
The effects do not occur in isolation and all influence each-other in some way
Do energy systems work in isolation
No- it is NEVER either or; energy systems work in tandem not isolation, it is just the contributions that differ
What effect does sprint training have
Increased glycolysis utilisation, increased.enzyme activity, increased transport proteins, hypertrophy
What is the energy contribution during a 100m sprint
50% PCr, 50% anaerobic glycolysis
What happens to energy contributions as exercise goes on
Shift to aerobic metabolism
