I know, I know, this topic is a bit old... but I'd come across a book that explained perfectly why there was no force in some of these pushes, and so much in others.
...then I forgot which book, otherwise I'd just scan it and I'm sure it'd be clear.
The basic idea is that you can draw a C-curve that follows the force of the body, and most of the force will be shootin' out the end of that C-curve. If the tip of the C-curve points UP (as seen in your earliest attempt) practically all the force will be directed UP, and as such y'ain't gonna get any force pushing against whatever you're trying to push against.
Demonstrated:
Furthest on left has some force "escaping" out of the top but the overall "S" curve that is formed is providing some force.
Next over is one of your earlier attempts. Practically all force goes straight up, and really weak force in the arms doesn't help the wimpy look
Ben's edit (I think?) in the middle shows most of the force travelling at what seems to be a 45, which is awesome. It does lose some force in the "pushing with my elbows!" bit... but that also makes it closer to your pushin' like a kid ideal.
Next over is just ruined by the multiple bends taken in its travel from shoulder to object. Every time you make a turn like that, you'd only be able to push as much force as the weakest joint could handle.
Next over was taken from somewhere in your walk cycle. It's actually quite effective because the C curve is quite harsh, harsher than I drew it actually (It'd go from his near foot to the peak of his back to his hands on the wall) and so most of the force is travelling into the object.
On the bottom is what I view as ideal.
I'm trying to figure this stuff out, still. If I'm wrong somewhere, give me a shout. We'll figure it out
(Edit : Found the page)
http://i3.photobucket.com/albums/y73/SaboteurGreg/Takam2.jpgTaken from
Wayne Gilbert's
Simplified drawing for planning animation