The runner breed is thought to be a couple of thousand years old, though no one has exact proof of that. They story goes that they were bred to run through rice paddies and clean up the bugs and cracked grain. The "shepherd" ran them from home through the paddies, stopping for a while at each paddy and then run them back home in the evenings. They were bred to run.
I've been meaning to buy Chris and Mike Ashton's book, "The Indian Runner Duck: A Historical Guide"