Does she try to lean on you? Mine used to, and then I had one trainer who told me that when he did that I was to "drop" him-like a hot potato. If there is no contact, they can't lean and learn to be on their own.
Well, its a combination of leaning and just being a turd. She will normally start out on my hand and after a few minutes of just walking/trotting around, stopping when she gets ahead of herself, backing up and changing direction, she will start to get the idea and mellow out and even do a nice slow jog that can be brought up to a more forward trot without much fuss.
At the end of our ride yesterday, I did the exercise above and when she would start to get carried away at a trot, I would just "heeey" and she'd be setting up to stop, and take her trot down a notch when I gave her a touch of leg after.
I just got onto this forum and starting eeading your thread but I do have some questions/input.
Firstly, as said make sure her tack fits and her back is fine. Ill fitting tack can end up causing all sorts of issues.
Also, how is she on the lunge line/ roundpen at a lope/canter? Does she have proper balance? It might just be that she's not fully balanced for what your asking and that's why she's all over the place. My gelding has been off for a few years due to an SI injury. Bringing him back into work is intersting as its completely different from when he went on pasture rest. If I were to ask for a canter now, he would be all over trying to balance himself out proper and it for sure wouldnt be comfy to ride.
To me it just seems like she hasnt been loped/cantered much and she doesnt have those muscles built up to do it. It takes time but if you do it right you will have a nice balanced horse.
As far as the run-it-out method, works for some and can be a huge mistake with others. My tb loved when we would do arena work at w/t/c and then head out on the long hill beside the barn and run a mile or so at a gallop. He would be pretty excited at first (but not out of control, I could always stop him anytime I wanted) After a minute or so he would calm right down and do a slower hand gallop. We would go a mile or so then trot for a minute or so then walk the rest of the way to cool out.
Another thought is that some green horses will just need to lope and lope and lope. Our greenies here get that. Lope around the rail, don't do much, just sit there and let em go. If you ahven't been loping her it's an idea that she just needs that.
Actually I just watched this issue get resolved on a thoroughbred yesterday. He was feeling good and refused to cooperate. And on circles he just kept wanting to run... So we decided "Okay, you wanna run? Then let's run!" And while he ran we kept pushing him until he decided he didn't wanna run anymore and slowed to a trot.
A slow lope is probably the most balanced one she can offer you. I'd do lots of transitions at that lope and just keep up with her. Don't make her go any faster because that won't just get her to "snap into place"
She's a green horse. That's more likely to get her to trip or not feel safe.