a study demonstrating the increased uptake of carbs caused by caffeine and its relevance to performance enhancement (no, not the type you get spammed about), especially in cycling:
http://www.foodqualitynews.com/news/new ... ine-sports
an article about the possible ban of caffeine in the austrialian football league:
http://foxsports.news.com.au/story/0,86 ... 17,00.html
if you're looking to break through "the wall" during a marathon, grab some caffeinated goo or the like. when your body runs out of stored carbs to burn (usually around mile twenty or so) it has to switch to burning fat, which is a much more difficult process for the body. caffeine speeds that conversion making it easier to break on through [to the other side!].
and meadows, thanks and i found this, too:
Because caffeine enhances performance in many individuals, it has been banned by the International Olympic Committee. But ironically, the level at which caffeine is banned far exceeds the amount needed to enhance performance. Higher, illegal levels are generally attained with caffeine supplements, since a 150-pound athlete would need to drink 3 to 4 large cups of coffee within an hour before activity to reach the upper acceptable limit. Just 1.5 to 3 milligrams of caffeine per pound of body weight (225 to 450 milligrams for a 150-pound man) is enough for an energy-enhancing effect. That's as little as one 10-ounce cup of coffee!