I'm like a CoD character: I can run seemingly indefinitely, as far as simply running everywhere that I need to go; but can only sprint for about thirty seconds, before having to slow down to a quick walk while wheezing like a fat kid with asthma. Only lasts about ten seconds, then I'm good for as far as need/want to go, until my joints refuse to hold up my weight.
I am by no means in shape; but by no means an immobile stump, like pretty much every fattie in existence.
I could probably go a mile, maybe two; and this is without being trained/prepared. After a while I'd go much farther, especially if water was provided, and it wasn't boring as hell.
So yeah, me -a few pounds + water +high quality running shoes +arthritis meds +some experience = an average/slightly above average runner.
And I don't mean jogging, either. I mean running. Not sprinting, either, but running.