creatine

______ may cause a modest rise in plasma concentrations, but ______ results in a significant rise.

1g; 5g

how much creatine does a 70kg male need per day?

2g

multiple daily doses (______) will dramatically increase total creatine content in skeletal muscle.

5g, 4-6 times daily

phosphocreatine (PCr):

a nitrogenous compound that participates in the production and maintenance of ATP (comprised of amino acids); assists in the regeneration of ATP

possible performance benefits from supplementing creatine:

based on time or duration of exercise; short duration/high intensity activities; improves high intensity exercise capacity, short bouts (30 seconds or less seem to benefit most from creatine supplementation)

why would the form of creatine used matter?

blended or combination formulations may not be readily absorbed by the body and therefore may not have any benefit

how does carbohydrate use effect the response to creatine?

creatine levels may improve if given with carbohydrate sugar solution

what is the most common form of creatine used?

creatine monohydrate

how does exercise affect the action of creatine supplements?

endogenous PCr gives up its phosphate molecule in order to assist in the regeneration of ATP; during intense exercise PCr reserves (in skeletal muscle) are depleted in seconds; ingesting supplemental creatine leads to increased creatine accumulation in muscle and therefore increases the amount of PCr available to regenerate ATP

why is creatine used?

enhance ahletic performance, used in treatment of parkinson disease and muscular dystrophy

how do creatine supplements affect exercisers' HR and oxygen uptake?

if athlete can train longer and harder, could indirectly lead to an increase in VO2

how do creatine supplements affect exercisers' body composition?

increase in muscle fiber types I, IIA, IIAB cross sectional thickness; increase in body mass while using creatine; including an increase in fat free mass in both males and females

how does creatine enhance athletic performance?

increase muscle mass (lean mass) and increase muscular endurance (# of reps)

how does caffeine use effect the response to creatine?

large amounts of caffeine used on a daily basis eliminated the benefits of creatine; 5mg/kg/day is equivalent to 3 cups of coffee in a 70kg male

creatine can be found in:

meat, eggs, fish

potential complications of creatine use:

muscle cramping, dehydration, loose stool, nausea, even death (excess creatine cannot be stored by the muscle tissue it must be excreted. nitrogenous compounds may cause damage to kidney function if ingested in large doses chronically)

how do creatine supplements affect exercisers' postexercise lactate concentrations?

no relationship between effects of creatine and post exercise lactate concentrations

NCAA and USOC status:

not currently banned; however, NCAAA places a warning on any and all supplements

guidelines for creatine use:

short term use is probably safe (in smaller quantities); exercise benefit may occur, so athletes should be discouraged from using during competition; recommended for deconditioned vegetarians who may begin exercising; avoid using caffeine; adverse kidney issues may occur especially when creatine and protein are used simultaneously

what about professional teams status on creatine use?

some professional teams (mostly NFL) have banned the use of creatine during the season

creatine is produced by:

the liver, pancreas, and kidneys

how does animal protein intake or lack of effect the response to creatine?

vegetarians typically have a lower baseline of creatine, so they usually see a great response to supplementation

what is IOC's views on any supplement in supraphysiologic amount?

views it as "doping"

does a loading dose seem to be beneficial for increasing creatine concentration?

yes