I would go back to groundwork. 99% of problems that people have on the back of a horse is because of the lack or inconsistency of the groundwork beforehand. Especially with Mustangs, the groundwork is important. They have to learn to respect, not fear you, and they need to know that you are the leader. Once they learn this, they will willingly obey you.
Take her to the round pen and take of the halter. Work on her forward movement, turns, and stopping. When she has is down, then halter her. Do the same. Flexing. Moving around her. Get her backing up. Backing a horse is pivotal, and something that will help them all the way around. I back my horses all over. Into their stall, down the barn hallway, into the wash rack, through gates. It keeps them soft and paying attention, and keeps that respect of 'my bubble'. Then saddle up and do all the same- from the ground still. Flap your stirrups. Put every obstacle in front of her that you can think of. Back her up. Flex her.
After she has had a considerable amount of groundwork done, then you can ride. Now she should have a much better sense of who is the leader, and she will have respect for you. When you are riding, be sure you have a one-rein stop. Have control at all gaits before you move up to the next one. For example, she should be able to walk relaxed on a loose rein and be able to one-rein stop and flex before you move her up to a trot.
If you have a good training regime and stay consistent, you will have less room for mix-ups and mistakes. The only time you can 'work her butt off' or anything like that is if she is fully trained, you know that she knew better, and if she deliberately threw you off. Which, if she has been trained right, she should not ever do this. Most of the problems that people have with their horses are not the horses fault.
I'm not trying to be harsh, but bucking is a serious issue, and I have seen it send many people to the emergency room with severe injuries. It is an issue that needs to be fixed, or it will only get worse with time.
American by birth. Cowgirl by the grace of God. And I wouldn't have it any other way.
Last edited by KayceeJo; 09-27-2013 at 08:09 PM.