Is this the same horse that you have talked about before or is this a different one? http://www.montyrobertsuniversity.com/forum/post/not-cantering
How's the Haflinger getting on ?

The haflinger hasnt yet arrived, she should do this weekend, anyway, this is my saddlebred mare, shes perfect to trot, walk in the arena all mm over now, she round perfectly and everything, not hot or fast at all anymore! But still, shes strong in her canter, she will tend to take off at the transition and will not round and relax like she does in the trot, she sticks her head up and gets excited, same goes for jumping. I have posted alot about her and how to fix problems because her oldowners didnt do her any good for her education under saddle and on the ground. Im just fixing problems bit by bit.

There's nothing wrong with posting a lot, just wanted to make sure we are talking about the right horse ;-) What is your name by the way, unless I've missed it you've never told us.

It seems you have made some good progress with her in the arena but it is early days, it will take time for her to feel confident and safe. I am a huge advocate of longlining and it is so valuable in situations like this. Now, having read your other post about her back legs you will get a doubel benefit from longlinging - it is likely she will kick them as the lines 'tickle' round her hocks so it's important to go very carefully so she doesn't speed off in a panic but the longlines are a good way of starting to desensitise her to feelings of things on her back legs while keeping you safe. The first step I think is to start with a soft line thrown on the floor/over her back/dropped over her rump down to her hocks so that she begins to feel the senstation of a line and that it won't hurt her - then you can progress to attaching the lines. You need to work in an enclosed space for this to start with (preferably circular) so she can't run away from you once she gets to the end of the lines. You can also use an extended arm like Monty does to desensitise her legs. Most important thing is the 'advance retreat' idea i.e. the scary thing goes away when she is quiet so that she does not think she has sent it away. Always have someone on standby to help for safety reasons when you are doing this sort of work.

My name is Lani. I have done long lining with her and she seems fine with the ropes around her back legs, but its her lower legs that I need to fix as when it hits her lower leg, she will either kick out or take off. I will try a few of your suggestions, thanks! I just dont like the safety issue with both her and other animals and humans. I would like her to feel safe :)

Hi Lani, it sounds like she's just young & sensitive regarding the long reins touching her hind legs & it's a very normal reaction especially for a mare, they do tend to be free with kicking out their back legs, it's just protecting herself, she'll get used to it.
Cantering: again, she's young / untrained and not balanced, so it's easier for to to run forwards with her head up, it'll take time for her to adjust her weight so she can carry her weight more on her hind legs.
Can you try very hard to keep your hands down & very soft & still when she canters in the arena? It's not easy, i know, but the softer & stiller you can be,( in your seat too) the more chance she's got of settling. I don't mean that you throw the reins at her, but keep a light steady contact with her mouth so she can find it with out you pulling. Means being pretty brave if she's running off!!

She may have got so strong because of the jumping, if she's been fired at jumps before she was strong enough or trained enough, she may have been frightened & so rushes the jumps.
You could put some poles on the ground around the arena at a later stage so you can ride over them at any time during your schooling so they just become part of ordinary life & so not be too exciting.

One thing I thought perhaps is she may be unbalanced? As she is now completely calm and lazy at walk and trot in the arena?

But shes not young and untrained. Shes 12 years old and was once owned a ridden frequently by a riding school. She is an allrounder, she jumps, neckreins, does pirouettes and turns totally by your leg aids, rounds, she is fine with the long reins aswell. She is dressage trained, used to showjump and jumped 1.2m,has done loads of campdrafting etc, was owned by that riding school so shes not uneducated or young so thats why im asking what to do. She has a jig joggy canter and throws her head up.

But she shouldn't be lazy in walk and trot - she should be going forward with some energy. I'm thinking she isn't putting any weight on her hind legs and fall on her front instead, which could be a reason for her to throw up her head and take off at the transition - she needs to get the weight off her fore limbs to start up the canter.
Have you had her back and hips checked? I would start there since the head thing also indicate a problem there. Maybe a chiro or physio can help you out?

I think Beryl and Kicki have answered it clearly Lani, her past experience may gave been having to rush at jumps without being properly balanced and trained to jump. If she is dressage trained she should be shifting the weight back but as Kicki says it would explain the head throwing. I know we have all suggested several times about getting her back and hips checked but you weren't financially able to do it at the time. Have you managed to get her looked at yet? I would strongly recommend a good equine physio that can put together some exercises that can help strengthen her. Riding school horses go through hell sometimes as they are often over worked, under cared for and under trained (not all obviously before any riding school owners shout at me hahaha)