Yes and no. It depends entirely on which type of zombie you find yourself up against. If they are of the 'plodding' variety (see Dawn of the Dead) then yes, the average human can indeed outrun a zombie. Remember however that you will need to stop eventually, as you need rest, they don't. If you find yourself up against a 'runner', like the ones in 28 Days Later, then to be honest, you've pretty much had it unless you can get to transport.
As well as not needing rest, Zombies don't feel pain and as a result can push their bodies well beyond the normal human pain threshold. You'll eventually get cramps and need to stop.