What are the effects/actions
of creatine?
Creatine, or methylguanidine-acetic acid, is a naturally
occurring compound. In healthy individuals the total amount
in the body is about 120g. Ninety five percent of creatine
is found in the skeletal muscle. Sixty percent of creatine
is in the form of phosphocreatine (PCr), which is considered
to facilitate increased anaerobic energy (Wolinsky, 1997).
The role of creatine in muscle energy metabolism and fatigue
is to maintain adenosine triphosphate (ATP) availability,
modulate metabolism, and buffer hydrogen ion accumulation
during contraction (Greenhaff, 1996). In effect, this means
that the student athlete would have more muscle energy and
therefore be able to do more intense anaerobic workouts.
Development of fatigue during short-duration exercises has
been associated with the depletion of muscle PCr stores
(Hultman et al., 1991).
What
are the adverse effects of using creatine supplements?
Reports related to creatine supplementation have indicated
that one third of individuals trying creatine supplements
are unable to absorb the extra amounts into their muscles
and experience no improvement in muscle mass or athletic
performance (Tarlach, 1998). Endurance athletes (marathoners)
may find creatine supplementation counterproductive since
the extra muscle mass creatine builds slows them down (Tarlach,
1998). Increased cramping and muscle strains may be associated
with intracellular swelling (Williams and Branch, 1998).
Endurance athletes may find creatine usage counterproductive
since the increase mass and increase in weight may contribute
to lowered endurance (Volek, 1997; Hultman, 1991). Recent
studies reported that a 25 year old soccer player developed
renal dysfunction while taking creatine. He had not exceeded
recommended doses. His renal function returned to normal
after he stopped taking creatine (Poortmans, Aucquier, and
Renaut, 1997; Pritchard and Kalra, 1998).
Do you have feedback for us about improving this page?
Are there questions we haven't answered or addressed? Here's
your chance to tell us what you think. Visit
our Feedback Page to speak your mind!
