It’s too late to find you data. But I can give you a very quick bit of reasoning.
two legs are more efficient than 4. A human foot is the most efficient foot in existence. (hopping bipeds have very efficient leg sinews...ie kangaroos and such)
straight legs are more efficient than bent legs. A straight legs resists gravity(at rest not in motion) primarily by compression forces resisted by bone...NO ENERGY EXPENDITURES REQUIRED. A bent leg resists gravity by way of continuous tension forces in muscles that resist bending of the bent joints.
A human being is essentially a pole sitting atop two pole like legs. A quadruped is essentially a beam held up by two crooked poles at each end of the beam. The beam is held straight by constant muscle action, and the 4 crooked poles are held up by constant muscle action. Muscle action IS CONSTANT CALORIC CONSUMPTION.
Humans have more stored body fat as a percentage of body weight than do horses.
In a death march between a human and a horse, the human would choose a speed slow enough to take advantage of his “at rest” efficiency advantage over bent leg quadrupeds. Also, a human’s ability to carry small amounts of food and water on his back or around his neck is a huge advantage. Maybe that’s cheating, but a human has the ability to cheat. A horse does not.
So the death march becomes a starvation contest in which the human is permitted a small amount of cheating and the horse is not...and the human has a more efficient body structure...and the human has more fat stores.
It’s no contest.
Dismissed.