Lizzie Wade looks at a couple of papers about spongy bone:
The hunter-gatherers’ hip joints were about as strong as those of the apes, whereas the ancient farmers’ hips showed a significant loss of spongy bone. The researchers conclude that a lack of rigorous exercise, rather than any evolutionary pressure toward lighter skeletons, is the reason for modern human’s weak bones. So if you want a stronger skeleton, start exercising like a hunter-gatherer.
Hmm. They looked at the hip joint, which you'd expect to get more of a workout in humans chasing after critters, though maybe not quite so much if the hunter-gatherer spends time setting traps or doing ambush hunting. I wonder how they distinguish those. A farmer probably gets more upper body exercise than a hunter--how do the arm bones compare? Or the hip joints of a racer? Or of a slave? (The "helmsman" found by the older! boat in Herculaneum had bone changes from his work.)
It is a bit surprising that some bones would be as strong as an ape's. How dense are the rest of an ape's bones? (quite a bit denser than human)