Exercise physiology (Energy, recovery, rehab, prep & training) P1 Flashcards
(299 cards)
Energy for Exercise
the food we eat ->carbohydrates, fats and proteins -> Carbohydrates broken into simple sugars -> glucose C6H12O6.
Glucose
- In blood stream can be stored in the liver or muscle cell sarcoplasm
- when exercised, glucose moves into mitochondria to break down anaerobically: C6H1206 -> 6CO2 + 6H20 + Energy
The ‘energy’ produced is used to resynthesise ATP.
ATP
-Adenosine Triphosphate
-High energy source
-Only usable energy source for muscle contractions
-takes 2/3s to use
ATP is where the energy from foods we eat is stored so it can be used
ATP Structure
- AN adenosine molecule attached to three phosphate molecules by energetic bonds.
- Bonds are unstable
ATP BREAKDOWN
- ATP -> Adenosine diphosphate + phosphate + energy - energy gets recycled energy system
- ATP-ase, enzyme, catalyses reaction
- Exothermic, gives energy out
ATP resynthesise
- Endothermic, absorbs energy
- ATP is used in 3 seconds so needs to be replenished immediately
- Happens through energy systems
- ADP + Phosphate -> ATP
ATP/PC - Alactic
- Deleted ATP stores trigger the release of creatine Kinase, triggers phosphocreatine -> phosphate + creatine + energy
- Anaerobically
- PC is a energy rich chemical produced by the body, in sarcoplasm
- Available for contractions of high power e.g. 100m
- Duration: 10seconds when sub-maximal
- 1:1 ration of PC to ATP production, a small store
Coupled reaction - ATP/PC
The products of breakdown of PC, by creatine kinase, are used to resynthesise ATP
-Energy produced from the PC breakdown is used to resynthesise ATP
Advantages of ATP/PC
Regenerated rapidly
PC Stores are replenished within 3 minutes
No fatiguing by products ( hence A Lactic , without LA)
The ATP/PC system can be extended through the use of a creatine supplement
Disadvantages of ATP/PC
Limited supply of PC in the body
Only 1 ATP molecule regenerated for 1 Molecule of PC.
Glycolytic System - Lactic acid
- After the ATP/PC system
- Regenerates ATP from the breakdown if GLUCOSE -> only if Phosphofructokinase is present (Enzyme)
- High intensity over 10 seconds & less than 3 minutes e.g. 400m/ attacking phase in football
- in absence of oxygen, Anaerobic Glycolysis -> Pyruvic Acid
- Longer exercise continues the higher the rise in LACTIC ACID AND pH levels -> inhibits enzyme activity -> fatigue & OBLA
Glycolysis - Glycolytic system
Glycogen -> Glucose, enzyme Glycogen Phosphorylase (GPP) -> 2 ATP moles and energy
Glucose is broken -> Pyruvic Acid, by Phosphofructokinase (PFK)
Pyruvic Acid -> Lactic Acid, enzyme Lactate Dehydrogenase (LDH)
OBLA
Onset Blood Lactate Accumulation
- at rest is 2mmol/L, increases depending on intensity of exercise
- At 4mmol/L OBLA is reached, a threshold beyond lactate production is greater than breakdown.
- > Exercise that is anaerobic eventually leads to exhaustion.
-> train muscles to delay the OBLA threshold, due to body’s ability to tolerate high levels of lactic acid.
Advantages of Glycolytic System
ATP regenerated quickly -> few chemical reactions needed
With O2 present, Lactic acid is converted back into glycogen -> recycles energy
Useful - produces extra burst of energy
Disadvantages of Aerobic system
Delay for oxygen delivery -> due to complex series of reactions
Slow energy production limits activity to sub-maximal intensity
FFAs demand 15% more oxygen for breakdown
Advantages of aerobic system
Large fuel stores ->triglycerides, FFAs glycogen & glucose
High ATP yield (38 ATP moles)
Long duration of energy production
No fatiguing by-products
Aerobic system - diagram
Free fatty acids -Aerobic
Long distance performers - glycogen stores, high intensity e.g. Sprint finishes
-Tryglycerides can be metabolised aerobically as free fatty acids, provide a huge potential store -> conserves glycogen+ glucose
Lipase converts triglycerides into FFAs + glycerol, FFA’s -> Acetyl CoA - go through link reaction in Kreb’s cycle -> ETC as PA
- Produce more Acetyl CoA + a higher energy yield -> long distance athletes with events longer than an hour
- Require 15% more O2 to metabolise - low intensity
Electron Transport Chain (ETC)
-last stage in aerobic energy system
Hydrogen released in Kreb’s cycle are carried through ETC, in cristae, by NAD & FAD -hydrogen carriers
-NAD & FAD split the hydrogens into H+ ions & H- electrons. These pairs of H carried by NAD release energy to resynthesise 30 moles of ATP, those carried by FAD release energy to resynthesise 4 moles of ATP
Hydrogen is oxidised removed as H2O
Overall releases energy to resynthesise 34 ATP moles
Kreb’s Cycle
-A CYCLE OF REACTION
Acetyl CoA + oxaloacetic acid -> Citric acid - oxidised through Kreb’s Cycle
-Site is mitochondria matrix
-CO2, Hydrogen and energy used for ATP resynthesise of 2 moles of ATP are released
Aerobic Glycolysis
Glycogen -(enzyme GPP) >Glucose, -(PFK)> Pyruvic Acid - creates enough energy to resynthesise 2 moles of ATP.
O2 is present -> Pyruvic acid goes through link reaction - catalysed coenzyme A -> Acetyl CoA - Gives access to mitochondria matrix.
Aerobic System
- During Low-Moderate intensity & long period of time e.g. Marathon
- Presence of oxygen allows continued energy production
- Utilises 95% of potential energy in glucose through Aerobic Glycolysis, Kreb’s Cycle and The Electron transport chain
- Uses free fatty acids to provide huge potential energy store
- Long Distance performers
Disadvantages of Glycolytic
Lactic acid is a fatiguing by-product
A small amount of energy is released from glycogen under anaerobic conditions.
Example of the energy systems contribution of a 800m race
- ATP/PC SPRINT START
- Glycolytic after the first 10 seconds for up to 3 minutes of high intensity
- As the intensity drops the aerobic system becomes predominant as there is sufficient o2 available