Steve Muhlberger asks for informed commentary on the article while expressing some skepticism.
I won't say anything about the value of calculating the speed of prehistoric aboriginals from their fossilized trackways, except that it's probably pretty difficult without knowing with some precision how long the legs were of the person that left the footprints.
But this I can speak to:
Roman legions completed more than one-and-a-half marathons a day carrying more than half their body weight in equipment.
This is lazy stupidity on multiple levels. A marathon is a foot race, and currently covers a bit more than 26 miles. "One-and-a-half marathons" would be nearly forty miles. At a run.
The Roman legions did not cover distance at a run. They marched. Marching is much less tiring.
That said, I don't know why McAllister thinks legions routinely covered forty miles a day. I'm baffled.
Assuming that McAllister never noticed that the Roman mile is shorter than the English mile only gets you part of the way there. An Iter Iustum, an ordinary day's march on good roads, might cover 15-17 miles.
Vegetius tells us that the Romans trained by marching ten Roman miles out and the same back (about 18 English miles) but they only did it three times a month. It was a conditioning exercise, not a daily routine.
According to modern US Army doctrine, the average rate of march for trained infantry under favorable weather conditions is 2-1/2 mph over roads and 1 mph cross country. A normal foot march covers 20 miles per day.
Currently, US infantry on the march carries loads comparable to a Roman legionairy soldier.