Originally posted by JimAmelung2
It seems there is a great body of evidence showing that creatine has no beneficial effects for endurance or sub-maximal exercise activities. Yet, logic dictates, (at least mine) that any additional creatine stores, like glycogen, will aid in prolonging exercise activity.
>Actualy, it tends to improve recovery of creatine stores between sprints rather than prolonging exercise or increasing exercise intensity in a single bout of exercise. As creatine is not used to a great extent in endurance or submaximal exercise, changing creatine levels will have very little effect on performance.
It's always been my perspective that it is very difficult to describe the "proportions" of various energy pathways invoked throughtout a given competition.
>In a road race the contribution of the ATP
C system is estimated to be <1%. Whereas the contrbutions of anaerobic glycolysis and aerobic metabolism make up the other 99%, much greater improvements in performance are bound to be seen here.
A hill presents and triggers an opportunity for some anaerobic muscle activity during standing, etc...... A tailwind allows for a period of complete aerobiosis.
>Given that the ATP
C system is likly to benefit efforts of <10 seconds, a hill lasting over 10 seconds would require a large component of anaerobic glycolysis and aerobic metabolism. Also should you hit the hill in a state of depleted creatine (at complete rest recovery of creatine stores takes over 2 minutes) you are unlikly to have creatine to contribute to the effort. Few hills or even sprint finishes are ridden at an intensity where the ATP
C system would provide a significant amount of energy.
I would suggest there is a possiblity that for some individuals
engaged in exercise activities of varying intensity, that additional creatine stores are some how beneficial. I admit, that I cannot decribe the differing metabolic pathways activated in "real life" situations that would support my inference.
>Agree, sports people that engage in sports with varying intesity do benefit from creatine. These people are footballers, etc. where exercise goes from max to allmost rest to max again. In road racing pace is far less variable. Perhaps there may be a benefit for track points racers, but only if the race happens to have long slow periods between races.
As I stated above, to prove creatine a benefit, a subject would have to demonstrate that a "lack of creatine" promoted a reduction in ATP synthesis during a given effort, something I doubt, will ever be demonstrated.
>Actualy, demonstrating that a 'lack of creatine promotes a reduction in ATP synthesis' does not infer a performance loss. Also by supplementing someone with creatine you create a whole population that are relativly depleted in creatine (i.e. non supplemented individuals). If you want to see the effect of creatine depletion on performance just do a series for 5 second maximal sprints with 30 second rests, you'll soon see your performance go down! After 5 or 6 sprints there would defineatly be a 'lack of creatine', but would this impact on endurance? Perhaps not.
