What effect does high levels of testosterone have for a cyclist?

I'm referring to the Floyd Landis story, of course. I know increasing red blood cells increases oxygen flow to the muscles, but what effect does testosterone have? Does it increase endurance? Or stamina? Or strength? Or something else?

What effect does high levels of testosterone have for a cyclist?
It increases all muscles growth, the way oxygen is absorbed by the blood cells, as well as how lactic acid is produced after a workout. Stamina, and motivation is increased 10x. CNN has just reported that when he finished racing, that instead of being over joyed and tired, he was wired and very angry as if he could punch a hole thru a wall. This aggression is sign numero uno of steroid use.
Reply:It makes them want to drink beer, belch, read Maxim and watch football on TV.