I often wonder exactly what type of "resistance training" our hunter-gatherer ancestors did. Specifically, I wonder if it was part of the actual hunting effort or the butchering of the meat. Lately, I have been thinking it's maybe more connected to the butchering activity.
For example, a person can run or sprint, and then feast, but that doesn't really lead to big muscle growth. Some of the 100-meter sprinters are muscular but that is due to weight training. So in this way, maybe running or sprinting doesn't "set up" the muscle to enlarge. But if a hunter was butchering the meat, then the meat is already in hand, and this might signal the body to get ready to "store" amino acids (build muscle). Said another way, anyone can run or sprint, but this is not a marker of a successful hunt, it is only a marker of hunting effort. The physical activity of butchering the meat is a marker of successful hunting.
One other clue is that resistance training is generally done while stationary. Stationary could mean that a hunter is no longer chasing the animal and has begun the butchering stage.
Here is one link to how the Hadza hunter-gatherers made decisions about what to eat, butcher, and transport. When I get some time, I would like to look into this more.