I read this cool piece on how a barefoot runner may never win a ultra trail race. One of the commenters said something very interesting:
"We were “built” to run from A to B with a maffetone pace. Not to get there as fast as we can."
I would tend to agree with this – if the endurance hypothesis is correct, then humans were built for long endurance runs at a sustainable pace. By a sustainable pace, I mean a pace that a person can run day in and day out for long distances. No one can run at race pace 2-4 times per week for long distances year after year.
Then, I was reading this interesting article that also talks about how elite athletes spend most of their training time at lower Maffetone-like intensities. The article talks about how "polarized" training – lots of volume at easy paces and a bit of high-intensity work - is most effective. The middle intensity (race pace) doesn't seem to contribute that much. In my view, it's probably more of an energy-draining pace, because you're working at a high heart rate over a prolonged period of time. In other words, it's something most people (including hunter-gatherers) would try to avoid if possible!