I don't want to derail your thread as I am in agreement that old-time fighters were in a class seperate from most modern athletes, that they trained hard, that they were tough as nails, none the less:
You're right, a lot of modern day tribal and hunter-gatherer's exist. You ask me where is the videos of them performing these physical feats. (though the videos themselves aren't always taken by anthropologists but other scientists as well, ethnographers, etc)
tara humara for running: http://www.youtube.com/watch?v=FnwIKZhrdt4
lol, "weird or what" (I know, a ridiculous show) but the info is fairly accurate enough.
I was watching a video the other day (BBC human planet, maybe), of some tribal, spear fishing in the water, he was just walking around on the bottom of the sea floor. http://www.youtube.com/watch?v=MgRpwESWPLM
(like the video points out, hold your breath with this guy see how long you can do it, just sitting there watching him)
You can also watch a lot of documentaries or specials on tribals/hunter-gatherers that highlight some of their physical abilities with or without weapons.
It's beyond impressive. The guy in the water, his heart rate goes to 30bmp, he goes 20meters down to the sea floor where the pressure is so intense that it "crushes" his chest, and squeezes the air in his lungs to 1/3rd of it's usual volume. I would venture to say the average man or athlete, would be hard-pressed to DO ANYTHING under those circumstances, let alone hunt, under-water.