Originally Posted by SunRoseHorsemanship
When I'm riding him without asking for collection, he carries his head very normally -http://www.youtube.com/watch?v=jiozHMkUDPk
But everytime I collect my reins and ask him to round up, he seems to really want to overbend and almost tuck up to his breast. I don't know what the previous owners were asking him to do, but it's hard to get him out of it. Even if I only ask for the SLIGHTEST bit of give, he just bend in the whole way. I almost can't see his ears when he does this!!
That's called getting behind the vertical, I believe. He's avoiding pressure from the bit. Have you tried lunging him in side reins, which encourage the horse to stretch out instead of curl up?
Well the more you ask for forward movement, start on a long rein at the walk, and very slowly gather up about an inch. But when you gather up (or shorten the rein) be careful not to jerk your horse in the mouth. When you shorten, let the horse walk forward and encourage the horse with your seat and leg.
Only go as short as you can BEFORE he starts curling up. Do you have a riding instructor or trainer that can help you? They'd be more helpful since they can see what's going on in person, not over the net.
But before you do ANY of that gathering, (except the side reins because those are very helpful) you need to encourage the horse to stretch. Long rein, forward impulsion at the walk, then try at the trot.. then if you're comfortable and he's stretching down, the canter.
Once he can stretch on a nice long rein, then start gathering up as suggested above. But over the span of some time. It's going to take awhile to help him realize it's okay to STRETCH and have contact.
EDIT: and if you have any pictures of him curling up and whatnot, be sure to post them!