Week 9 - Creatine

Question 1

Where does creatine come fromwithin the body?

Answer 1

Synthesised from Amino Acids in the liver, pancreas, and kidneys
95% is stored in the skeletal muscle

Question 2

Where is creatine stored and what are the measurements.

Answer 2

About 2/3 of intramuscular creatine is phosphocreatine with the remaining being free creatine
Total creatine pool in the muscle averages about 120 mmol/kg dry muscle mass.
Vegetarians have been reported to have lower intramuscular creatine stores (90-100 mmol/kg dm)

Question 3

Explain the creatine turnover

Answer 3

Synthesis - 2g/day 1g endogenous, 1g exogenous (diet)
Excretion - 2g/day creatine (urine)

Question 4

What is a method used to increase creatine levels

Answer 4

4 x 5 g (20 g) creatine per day for 5 days research as shown this to be effective.

Question 5

How can creatine supplementation be used effectively alongside a training type?

Answer 5

Creatine supplementation alongside resistance training promotes a small increase in the direct measures of skeletal muscle hypertrophy in both the upper and lower body

Question 6

What are the effects of increased creatine levels

Answer 6

Increased PCr resynthesise leads to short-term, high-intensity exercise capacity to perform repeated bouts of high-intensity effort

Question 7

Creatine metabolism during exercise

Answer 7

PCr levels higher in type 2 fibres than type 1.
Pcr levels decrease during maximal exercise.
PCr can be depleted in - 10 seconds
80% re-synthesised in 4 minutes

Question 8

Mechanisms of Action

Answer 8

Supplementation with Creatine:
Increaed:
Cr stores 30% = Increased PCr resynthesis
Muscle glycogen
Growth factor expression
Could increase protein synthesis
Training harder, longer = increase lean mass / strength
Decreased muscle damage

Question 9

Creatine sources externally

Answer 9

Diet (red meat (beef/pork) and some fish (tuna, sal on cod)) but not enough
Creatine monohydrate-
- White powder, 99% absorbed
- Significant amount of evidence
- Better uptake mixed with a carbohydrate containing liquid or food
- synthetic (suitable for vegetarians and vegans)

Question 10

Creatine loading protocols

Answer 10

Short, high dose protocol:
- 20g/day (split in 4 doses) for 5 days
- 0.3 g/kg BM (split in 3-4 doses) for 5 days
Long, low dose protocol:
- 3-5g/day for 20-30 days
Maintenance dose:
- 2-5g/day
Washout period = 4-6 weeks

Question 11

Co-ingestion of creatine

Answer 11

When co-ingested with protein and Carbohydrates or high carbohydrates whole body creatine retention increases (4 x5g creatine)

Question 12

When should it be used

Answer 12

Single (+1-5%) and repeated bouts (+5-15%) of high-intensity exercise
High intensity max efforts <150 sec, largest effects on <30sec tasks

Question 13

Can creatine help with endurance exercise

Answer 13

Exercise has shown that a combination of creatine and carbohydrate loading may increase power output during repeated high-intensity sprint efforts during the late stages of prolonged time trial cycling

Question 14

How can creatine help with concussions

Answer 14

Improvements in cognitive processing in the brain and potentially reduced damage and enhance recovery from mild brain injury/concussion

Question 15

Indivudal variability - baseline levels of muscle creatine

Answer 15

Individuals that have high muscle creatine levels will experience low creatine uptake from supplements. So therefore individuals with low muscle creatine levels will experience the greatest potential for increases in responses to supplementation

Question 16

When would creatine not be useful?

Answer 16

In sports where performance is not determinded by PCr availability creatine supplementation will likely not have any effects.

Question 17

How does creatine impact body mass

Answer 17

Increases body mass 1-2kg likely due to the increase in water retention. It may be counteractive for the performance for endurance and/or other weight sensitive sports.

Answer 18

There is no evidence that creatine supplementation causes kidney damage, muscle cramps etc

Question 18

What are some of the safety issues of creatine?

Answer 18

1. No evidence of adverse effects with long term supplementation at appropritate dosages in healthy individuals
2. Mild, temporary gut upset can occur. Can be fixed with split dose, longer loading protocol and avoidance of high fibre food with ingestion.
3. Contamination - all supplments have a doping risk. Athletes should only use batch-tested supplements