Anyway, we were trotting, and she was arching her neck and "bumping" her hind end a little, like horses do when they are thinking of bucking. I kept her trotting and gave her a vocal discipline every time she "bumped". I thought she was over it, so I asked for a lope. She went into it real nice and easy, but after a lap or so around the arena, she started putting her neck down again, arching it like she had been. I didn't know if this was her trying to "submit". I know when horses are relaxed and thinking and listening to what you want, they will often put their head down as submission. So I wasn't doing anything about it and she started bucking. I pulled her around in a tight circle and kept her going. A trainer that happened to be watching was kind enough to roundpen her, after which she settled down. We didn't do any loping after she was roundpenned, just some slow poles and trail work, so I don't know if she would have loped fine after.
The question I really have is this- is there a way to tell if they are putting their head down like "Ok, I'll do whatever you want", or if they are putting thier head down to buck? Is it possible that she was having pain, maybe in her back? Thanks!