Scientist have found that "mouth rinsing" with sports drinks during exercise increase performance by 2-3 % during 30-60 minutes activity. This is the same performance gain as when athletes were consuming the sport drink.

They think this is because of the effect on the CNS and not the glucose providing energy, since glucose takes some time to digest.

Which leads me to my question:

How long time does it take before glucose can be used as energy by the muscles? Is there any advantages in time using glucose in sport drinks compared to sucrose or fructose? Or is this time negligible?

Jeukendrup, A.E. & Chambers, E.S. (2010) Oral carbohydrate sensing and exercise performance. Curr Opin Clin Nutr Metab Care. 13(4):447-51

interesting paper!

the simple answer to your question is there is at best a very small difference.

Energy drinks mostly contain sucrose/fructose which will get absorbed and broken down into monosaccharides in the small intestine rapidly. from there they reach the muscles within minutes.