@rynsey I get that sometimes you just don't want to get on the floor, or you have knee isuees or whatever the reason might be. The problem with standing vs quadruped&co is that you cannot change the direction of gravity. It becomes a different exercise. Not necessarily bad or useless, but different.
Yeah, Dan calls it vertical bird dog, but is it really? In a bird dog you are extending the leg against gravity, but when you stand, you are doing the opposite movement against gravity. I always figured the marching he includes in fairly many programs is a standing version of crawling, with the point being mainly movement and the nervous system, and not muscles so much, and that is similar in a bird dog and a "standing bird dog". I'm no Stu McGill so I don't know if he would consider the standing version an okay replacement.
I understood what you mean with your standing back extensions and I don't think the pause changes anything. When you are leaning back, the gravity is pulling you down, not so much your back extensors and your abs are very much working to not let your bend too far backward. You don't even have to use any muscles and you can basically rest on the spine, which is ... not good. Same kind of bad we do a lot when slouching without any muscle activity. Resting on the spine, hoping the ligaments keep us up.
But sure, you can engage your back extensors in any position and any alignment. Gravity will make things easier or harder. Prone back extension is pretty easy to understand as you must work against gravity. When you are standing, gravity is already doing the work and you must contract your muscles against nothing, or your abs. And the abs will need to do the work to fight against both your back muscles but also gravity.
So, depending on the goals I suppose there is overlap in function. If you really get the same result from prone and standing versions, I can't really argue with that. You do you.
