The jogging vs. running thread got me to thinking about my childhood training. When I was in Boy Scouts, 60 years ago now, we could cover a lot of ground by running for 1000 paces and walking for 1000 paces, then repeat. The number of paces wasn't important, what was important was to step right out while walking and cover some ground while running. Once you were in shape, you could keep it up for hours while carrying a light pack. I lived 7 miles from school, and could do that distance in an hour and a quarter if I couldn't catch a ride, carrying homework and a trumpet in a case.
I know marathon runners run for hours, but tend to forget that Pheidippides actually had somewhere to go, and needed to get there ASAP. To be authentic, marathon runners need to do it carrying a sword and shield and wearing an iron helmet. Of course it killed him, so maybe the rule change was wise.
People used to run to get someplace. According to his autobiography, Benjamin Franklin once did a 20 mile round trip commute every day on foot. If he didn't have a horse, my grandfather used to call it "shanks mare." The guy who set the record for Mexico to Canada on the Pacific Crest Trail did it by the run and walk method.