It just occurred to me, as I move slowly back to yoga and other stretching and strengthening exercises after a knee replacement, that we homo sapiens likely evolved, at least in all the places we hunted, to crouch when we hunted, fought, or played in the foliage.
Probably even before we were homo sapiens our ancestors were crouchers. We needed to stay halfway down on our knees, sometimes for prolonged periods, hiding below the bushes or behind the chunks of ice, etc., and be ready to jump out, or jump up and/or send a spear or arrow or slingshot to the hunted critter, or to the enemy.
That's how I think we evolved as hunter gatherers, and being able to crouch and jump up was a critical survival capability. It takes strong legs, flexible knees, and coordination. Some athletes have it, and so do many youngsters. But as we age we lose that flex and pounce capacity rapidly, if we’re not careful. It potentially points to a larger mobility challenge and opportunity, which requires those muscles and more.
I say this because when one has had a knee replacement, being able to crouch and spring up fluently is the golden fleece, and may or may not be regained fully. Even a rough approximation will make me happy!
Gotta do that PT!