Problem going to canter in the school

Question
Hi there,
We have a 6 year old 17.3 hand Irish Draught who we are just getting to start jumping. He was terribly badly abused before we got him and we have coped with many many problems and cured most of them and are working on the rest.
He has superb riding manners, and is enthusiastic, brave and fun, he canters no problem when he's out, show him a green or a hill and he can't wait to get off, but we're damned if we can get him to do it in the school.
He has lovely paces in canter and collects or extends as asked, he will also yield and turn in canter light as a feather, all discovered when we are out!
He does very occaisionally try it in the school and gets lots of praise when he does but we just can't seem to make it stick. He adores jumping and always lands in canter, but hasn't got the idea of approaching the jump in canter nor maintaining it. He is completly fit enough, and jumps clear from the trot to 3.5 feet. We're not sure if it's because he can jump from the trot that he does - in other words he doesn't see why he should put more effort in, or what.
He doesn't lunge as yet, all he does at the moment is come in, when we started with him he was too aggressive to lunge, so we are now working with a pressure halter and using Pat Parelli techniques to get him yielding etc which he is getting really well and enjoys the work, he finishes completely chilled out.
He's a bright lad, picks things up incredibly quickly, but some advise on how to get and maintain his canter in the school would be great.
Many thanks, Fiona  

Answer
Hello Fiona! The first thing that comes to my mind about your horses cantering issue is that the areana where you are asking him to canter might be to tight of an area for him? This is the first thing to come to my mind because you said he has no problem cantering when you are out riding just when you are at home schooling. He is a big boy and needs a bit of space. Have you tryed to perhaps set up a jump course out side of the arena and jump him there? If you are riding him in a large areana with plenty of room for him to canter, the other thing I suggest is to do alot of arena work on the flat. Get him cantering and do lots of patterns like figure eights and serpentines to keep him guessing and work on keeping him at the canter. Lots of leg yeilds may also help. you may also need to cary a crop with you when you ride keep it pointed out slightly so he can see it and as soon as you feel him slowing just flick it and say canter on just to get his attention. Im very glad to hear that you are using Parelli Im a big fan of Monty Roberts myself but they both have the same concepts....well I hope that i have helped you out some let me know if i can be of any more assistance

Heather