Energy metabolism Flashcards
What are the 3 pathways of ATP synthesis?
- Creatine phophate
- Anaerobic glycolysis/lactic acid
- Aerobic glycolysis/oxidative phosphorylation
Creatine phosphate pathway - describe speed of action, amount of ATP produced, and duration of action
Speed: very fast
Amount of ATP produced: very small
Duration of action: very short (5-10 sec)
Anaerobic glycolysis - describe speed of action, amount of ATP produced, and duration of action
Speed: fast
Amount of ATP produced: small
Duration of action: short (1-2min)
Aerobic/oxidative phosphorylation - describe speed of action, amount of ATP produced, and duration of action
Speed: slow
Amount of ATP produced: large
Duration of action: very long
How much creatine will you attain a day if you consume beef and fish in your diet?
1-2g/day
If creatine is not consumed in the diet, how can the body synthesize adequate amounts?
Liver and kidney can synthesize adequate amounts from amino acids if not consumed in diet
Why do storage levels of creatine decrease with age?
Because creatine is stored in the muscle and with increased age you have decreased muscle mass
What is the main benefit of creatine supplementation?
Increased rate of creatine phosphate resynthesis during recovery from bouts of exercise
How much can creatine phosphate concentration increase with supplementation?
Up to 20%
Why are some people non-responders to CrP supplementation?
Because their CrP concentrations are already near maximum
What is the loading for CrP supplementation?
Fast loading: 20-25g over 5 days
Slow loading: 3g/day for 28 days
Elevated levels are maintained with supplementation with 2-3g/day
Co ingestion with 75-100g of CHO enhances Cr acumulation
Once supplementation with creatine is stopped, how long does it take to return to normal creatine levels?
4-5 weeks
Why is supplementation with creatine accompanied with 1kg weight gain?
Mostly water weight due to reduced urine output
How is creatine excreted from the body?
Excreted as creatinine - urinary creatinine levels will be higher, elevated blood creatining is a measure of kidney failure, chronic illness or skeletal muscle breakdown
Who is creatine supplementation best for?
Most effective for strength/power athletes as it has an indirect effect that allows increased training that improves strength, speed or power
Describe creatine phosphate system.
CrP is high energy like ATP - it is not directly used for energy but release of energy from its phosphate bond is used to rephosphorylate ADP to ATP
Describe how anaerobic glycolysis/lactic acid system causes metabolic acidosis.
Lactate produces acidity and this drop in pH can interfere with metabolic enzymes/cellular processes resulting in muscle fatigue
The lactate itself is fine as it is removed from circulation by conversion to pyruvate
What sports is the anaerobic glycolysis/lactic acid system used for?
Primary fuel source for exercise lasting 20-30 seconds eg netball, tennis, cricket
Why is BiCarb loading uself as supplementation?
BiCarb is absorbed into the blood, lowering acidity (acts as a buffer) so the body can produce more lactate without acidity and muscle fatigue
What is the best way to reduce side effects of BiCarb loading (diarrhoea, nausea, vomiting, stomach pain)
Consume as capsules 150-210 min before event with CHO rich meal
If an athlete was going to use traditional bicarb soda as a supplement - how would they take it?
0.3g/kg BM 1-2 hour before exercise
What sports is the anaerobic glycolysis / lactid acid system primarily used in?
Long sprints eg 400m, repeated sprints e.g soccer, netball, footy, hockey, repeated high force activities e.g 10-15 reps of weights, 50-100m repeated swims
What sports is the aerobic / oxidative phosphorylation system predominant in?
Endurance exercise e.g long distance running, walking, cycling, jogging, dance
Describe the basis of B-alaninne supplementation.
B-alanine is the limiting factor in carnosine production which improves Ca handling
When is B-alanine useful?
To improve performance when pH decreases due to increased ATP generation eg sustained events lasting 1-7min, repeated bouts of high intensity eg rowing, swimming, interval training, raquet sports, or high intensity at end of event eg cycling, running
What is the protocol for B-alanine supplementation?
5-6g/day (65mg/kg/day) increases muscle content by 60% after 4 weeks, 80% after 10 weeks
Efficiency is enhanced when taken with CHO meal
How do you reduce side effects (pasathesia) that come with B-alanine supplementation?
Use a slow release formula and split doses
What are the other 3 ways of producing energy?
Fat oxidation, protein oxidation and alcohol metabolism
What is the disadvantage to fat oxidation as an energy source?
Slow ATP production, need O2, can also form ketone bodies
What is the disadvantage to protein oxidation?
Least desirable energy source as it promotes muscle breakdown
