Ive had him get tired using the old tapping method on the XBox , he can still run a fairly long distance though. Kinda odd how holding the button is slower than tapping it though.
I have the 360 and he's never gotten tired. I think he goes as long as you're tapping the A button fast enough. I'm going to go with user error as well.
Fuck that. It sucked ass. I knew how to ride the bikes and drive the cars and my skill should be based on that, not some stat that you get through the game.