Energy metabolism

Question 1

What are the 3 pathways of ATP synthesis?

Answer 1

1. Creatine phophate
2. Anaerobic glycolysis/lactic acid
3. Aerobic glycolysis/oxidative phosphorylation

Question 2

Creatine phosphate pathway - describe speed of action, amount of ATP produced, and duration of action

Answer 2

Speed: very fast
Amount of ATP produced: very small
Duration of action: very short (5-10 sec)

Question 3

Anaerobic glycolysis - describe speed of action, amount of ATP produced, and duration of action

Answer 3

Speed: fast
Amount of ATP produced: small
Duration of action: short (1-2min)

Question 4

Aerobic/oxidative phosphorylation - describe speed of action, amount of ATP produced, and duration of action

Answer 4

Speed: slow
Amount of ATP produced: large
Duration of action: very long

Question 5

How much creatine will you attain a day if you consume beef and fish in your diet?

Answer 5

1-2g/day

Question 6

If creatine is not consumed in the diet, how can the body synthesize adequate amounts?

Answer 6

Liver and kidney can synthesize adequate amounts from amino acids if not consumed in diet

Question 7

Why do storage levels of creatine decrease with age?

Answer 7

Because creatine is stored in the muscle and with increased age you have decreased muscle mass

Question 8

What is the main benefit of creatine supplementation?

Answer 8

Increased rate of creatine phosphate resynthesis during recovery from bouts of exercise

Question 9

How much can creatine phosphate concentration increase with supplementation?

Answer 9

Up to 20%

Question 10

Why are some people non-responders to CrP supplementation?

Answer 10

Because their CrP concentrations are already near maximum

Question 11

What is the loading for CrP supplementation?

Answer 11

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

Question 12

Once supplementation with creatine is stopped, how long does it take to return to normal creatine levels?

Answer 12

4-5 weeks

Question 13

Why is supplementation with creatine accompanied with 1kg weight gain?

Answer 13

Mostly water weight due to reduced urine output

Question 14

How is creatine excreted from the body?

Answer 14

Excreted as creatinine - urinary creatinine levels will be higher, elevated blood creatining is a measure of kidney failure, chronic illness or skeletal muscle breakdown

Question 15

Who is creatine supplementation best for?

Answer 15

Most effective for strength/power athletes as it has an indirect effect that allows increased training that improves strength, speed or power

Question 16

Describe creatine phosphate system.

Answer 16

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

Question 17

Describe how anaerobic glycolysis/lactic acid system causes metabolic acidosis.

Answer 17

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

Question 18

What sports is the anaerobic glycolysis/lactic acid system used for?

Answer 18

Primary fuel source for exercise lasting 20-30 seconds eg netball, tennis, cricket

Question 19

Why is BiCarb loading uself as supplementation?

Answer 19

BiCarb is absorbed into the blood, lowering acidity (acts as a buffer) so the body can produce more lactate without acidity and muscle fatigue

Question 20

What is the best way to reduce side effects of BiCarb loading (diarrhoea, nausea, vomiting, stomach pain)

Answer 20

Consume as capsules 150-210 min before event with CHO rich meal

Question 21

If an athlete was going to use traditional bicarb soda as a supplement - how would they take it?

Answer 21

0.3g/kg BM 1-2 hour before exercise

Question 22

What sports is the anaerobic glycolysis / lactid acid system primarily used in?

Answer 22

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

Question 23

What sports is the aerobic / oxidative phosphorylation system predominant in?

Answer 23

Endurance exercise e.g long distance running, walking, cycling, jogging, dance

Question 24

Describe the basis of B-alaninne supplementation.

Answer 24

B-alanine is the limiting factor in carnosine production which improves Ca handling

Question 25

When is B-alanine useful?

Answer 25

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

Question 26

What is the protocol for B-alanine supplementation?

Answer 26

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

Question 27

How do you reduce side effects (pasathesia) that come with B-alanine supplementation?

Answer 27

Use a slow release formula and split doses

Question 28

What are the other 3 ways of producing energy?

Answer 28

Fat oxidation, protein oxidation and alcohol metabolism

Question 29

What is the disadvantage to fat oxidation as an energy source?

Answer 29

Slow ATP production, need O2, can also form ketone bodies

Question 30

What is the disadvantage to protein oxidation?

Answer 30

Least desirable energy source as it promotes muscle breakdown