What is ATP and why do we need it?
ATP = adenosine triphosphate is the body’s energy currency
What is the equation for ATP breakdown and energy release?
ATP —-(ATPase)—-> ADP + Pi + Energy
ADP = adenosine diphosphate Pi = inorganic phospate
What is the equation for ADP rephosphorylation?
ADP + Pi + Energy ——–> ATP
How does storage of ATP occur?
ATP stores are limited thus food sources need to be continuously catabolised (broken down) and transferred to the cells for storage as ATP
Which main bodily processes use ATP?
What are the three energy systems?
Explain the Creatine Phosphate System/
ATP-PCr (Anaerobic)
PCr + ADP Cr + ATP
PCr= Phosphocreatine
Larger amounts of Creatin stored in muscles than ATP (around 5X)
Rapid response to exercise, predominant energy source for short/ rapid exercise (e.g. 100m sprints, 3-15 seconds) with the rate of energy transfer being 4-8 X that of aerobic metabolism.
Immediate activation yet rapid depletion, replenishes within minutes of ceasing exercise
Explain the Glycolytic/ Lactic Acid System
Breakdown of glucose to form pyruvic acid and lactic acid
What are the two main processes involved in the Glycolytic/ lactic acid system?
End product is lactic acid
When and how can lactate be used in the body?
At lower exercise intensities, the production of lactate is usually met by the clearance of lactate through its use (via the blood) in:
What is the equation for the anaerobic glycolytic system? *****
Glucose —> Pyruvic Acid —> Lactic Acid
C6H12O6 + 2(ADP + Pi) —> 2 lactate + 2H+ + 2ATP
Produces lactate, hydrogen and ATP
Explain Oxidative or Aerobic Metabolism
Predominant fuel for sustained activity (beyond 2-3 minutes)
Prolonged submaximal endurance-type activities E.g. marathons
Oxidation or breakdown product of glucose of fatty acid catabolism to form AcetylCoA
What is the relationship between fuels and exercise intensity?
As exercise intensity increases the reliance on fat as a fuel decreases and the reliance on on carbohydrates increases
What are the three types of skeletal muscle fibres?
Type of muscle fibre is genetically determined
How do muscle fibre types differ?
They differ by both contractile and metabolic characteristics
How are muscle fibre types classified?
They are classified by:
Giving rise to:
Explain Type I muscle fibres
Type I muscle fibres
Slow-twitch oxidative fibre
Large amounts found in marathon runners
highly fatigue resistant with slow contraction speed
High myoglobin content, high mitochondrial content (mitochondria oxidative phosphorylation takes place- aerobic metabolism takes place)
Explain Type IIb muscle fibres
Fast-twitch glycotic
Rapid contraction speed
Highly fatiguable
E.g. Sprinters
Explain Type IIa muscle fibres
Combination of Type I and Type IIb
What occurs during prolonged sub-maximal exercise?
Glycogen depletion which results in fatigue
When/where is glycogen used?
Glycogen is used only in active muscles.
When glycogen stored are depleted then glucose (from the blood), fat and protein are used
Along with glycogen depletion, what are other contributors to fatigue?
What are some strategies of delaying fatigue?
Nutritional strategies to delay onset of fatigue during prolonged sub maximal exercise
What causes Fatigue during HIT?
Fatigue during High Intensity Training (HIT) has been associated with:
Acidosis
- disturbance in Calcium homeostasis
- loss of potassium from muscles