Creatine Flashcards
Where is creatine synthesized in the body?
In the liver, pancreas and kidneys
What amino acid precursors are creatine made from?
arginine, glycine and methionine
What % of creatine is stored in skeletal muscle?
> 95% - approx 50% is obtained from the diet
How are intramuscular creatine levels split?
2/3 = PCr
1/3 = free creatine
What is the average total creatine pool in muscles?
120 mmol/kg dry muscle mass
upper limit = 160 mmol/kg dry muscle mass
What is the average IM creatine stores in vegetarians?
90-110 mmol/kg dm
Creatine turnover - how much creatine do we synthesize + excrete per day?
Synthesis ~2g/day
Excrete ~ 2g/day
What are the effects of creatine supplementation?
↑ PCr resynthesis = short-term, high-intensity exercise capacity to perform repeated bouts of high-intensity effort
What muscle fibres are PCr levels highest in?
Type II fibres
How quickly can PCr be depleted?
~10 seconds
How long does it take to re-synthesise PCr?
80% re-synthesised in ~4 minutes
Takes much longer for 100%
What are best dietary sources of creatine?
Diet (red meat [beef/pork] and some fish [tuna, salmon, cod, herring) → but not enough
When is creatine monohydrate better up taken?
Better uptake mixed with a
carbohydrate containing liquid or
food (consume quickly after mixing)
Creatine loading protocols - what is the short, high-dose protocol
- 20 g/day (split in 4 doses) for 5
days - 0.3 g/kg BM (split in 3-4 doses)
for 5 days
Does creatine have acute effects?
No. Loading protocols are needed
Creatine loading protocols - what is the long, low dose protocol?
- 3-5 g/day for 20-30 days
What is the maintenance dose for creatine?
- 2-5 g/day
How long is a creatine washout period?
4-6 weeks
Co-ingestion - why is it advisable to co-ingest creatine with carbs?
Transport and storage of creatine linked with insulin availability.
Also shows to have high whole body creatine retention with high CHO diet + protein-CHO diet.
When is creatine best to be used(what types of exercise)?
Single (+1-5%) and repeated bouts (+5-15%) of high intensity exercise.
High-intensity max efforts <150 sec, largest effects on <30 sec tasks.
Why would creatine supplementation during endurance exercise be a potential issue?
Causes an increase in body mass
Why could creatine have an affect on concussion?
Improvements in cognitive processing in the brain and potentially reduced damage and enhance recovery from mild traumatic brain injury/concussion
What individuals have the greatest potential for increases in creatine supplementation?
Individuals that have high muscle creatine levels will experience low creatine uptake from supplements, and vice versa. Therefore, individuals with low muscle creatine levels (e.g., vegetarians) have the greatest potential for increases in response to supplementation.
What are the ‘concerns’ about creatine?
- Increase in body mass
- Myths
