Here is a picture of a back crunch and an Obeisance which is labeled as a bow, that is also called a front crunch. How is that for confusing? viewtopic.php?f=7&t=479
(scroll down to the C's)
I think a head up position is good for the back crunch...if your horse already parks out, you already have the back crunch!
Then you can try luring to ask the horse to lean back from the back crunch into the obeisance, or you can do what I did, and use the cordeo to cue leaning back. This took awhile for Tam to figure this out, but by rewarding the tiniest try that didn't involve moving his feet, he soon began to explore the possibilities of leaning back. So I asked him to lean back, but I also used a treat to lure him to lower his head (which I think they HAVE to do anyway to get in that position.
If you can lure them from between the legs (make sure they are balanced and won't fall on you), you can get a very pretty obeisance with the forehead nearly on the ground.
To further complicate things, I never have taught Tam to do the back crunch (parking), but he has a really nice front crunch (obeisance). He figured out he had to move his hind feet back in order to stretch down. I don't ask for any specific head position with him, other than to lower it and lean back. He doesn't put his forehead on the ground.
My issue with Tam was that he would knuckle over one or both font legs while leaning back/down to reach the treat. So I saw this video of Kabir (Bettel is on the forum)http://ca.youtube.com/watch?v=muQ5te0lB ... re=related
And I saw how putting the hands on the top of the legs could help to keep the knees from bending. So I tried it with Tam and it worked! Tam has a workable (not necessarily beautiful) obeisance. But the hand on the leg has really become the cue now.
Cisco has only a rudimentary front/back crunch. He hasn't yet seen the point in doing it I guess! He has his own way of doing things, and where he'll concede an occasional one or two knee bow (totally his choice of course), obeisance seems not to interest him, and in his personal opinion, the back crunch is mostly useful for peeing and not much else.
I have this little video of Tam that has his obeisance in it:http://ca.youtube.com/watch?v=z2r6U_3wDGI
In that video, I use pointing a lot...I don't do that anymore...it was confusing Tam! That video was from last March...we've learn a little since then!(Post edited after causing crunch confusion! Thanks Romy!)