The canter is the gait that is the most difficult to improve. That is why you watch a prospective horse at all gaits, but pay special attention to the canter, because if it sucks, it will always be a bit 'sucky'.
Actually the trot is the hardest gait to improve, not the canter. The canter can gain cadence, length, and strength moreso than a trot. I can influence a good canter and teach more there than a trot. Most dressage instructors I've worked with at the upper level have been of this mindset as well.
Canter work is fun!!
So, what you are describing is totally normal in a horse that is out of condition and hasn't been cantered in 1.5 yrs. Holding collection is hard, and he just doesn't have the muscle strength yet.
So help him out by changing within and between the gaits.
Begin with walk, so he understands what you are doing. Slow walk, medium walk, extended walk. Do this for a couple of circles, each direction.
Then between the gaits; w/t/c do this also for a couple of circles, both directions
Then at trot; slow, working, extended
Walk sets, trot sets then can add canter sets (slow, working, extended) after a week or so.
Another good exercise is to spiral in and out on the circle in all three gaits.
Finally, you can set up four cones approximately 5 meters off the rail, spaced out evenly, like corners on a square.
First at walk, walk around the rail, and every time you come to a cone, do a small (10 meter) circle around the cone, then continue on. Once he understands, then do it at trot and finally canter. If he breaks into trot around the cone, that is ok. Reward any try, and move the cones farther out if necessary.
Endless circles, especially that large (40x50 meters) is not really teaching him anything.
If you can rate his pace, and gait, back and forth, he will be listening to you and learning. The changes of pace within the gait is the way to teach beginning collection and balance.
Hilda Gurney once said "Practice doesn't make perfect; perfect practice makes perfect."
Endless circles at canter is not perfect practice. Trying to force collection when the horse is not strong enough or thinking forward is not fair to the horse and will increase his anxiety.
Praise early and often, so he knows what you are asking.
I wouldn't suggest any of this, especially at the bold. First off, a 10m circle is a highly advanced dressage move, not introduced until a mid level except for the half 10m from the rail to x. But I don't agree with that in the novice eventing test anyhow.
A circle that small won't really teach him anything other than 'my head is now curled in, my body is falling, and now my anxiety is back!'
As for spiraling, once again something I would do with a more schooled up horse. I use it for definition of the lateral aid prior to lateral work on young horses and for strength training in horses with bad stifles. For this horse, who cannot balance on a 40m circle, spiraling down would result in the above mentioned anxiety peak.
Her trainer is correct, and I'll explain more below.
If you are comfortable or know someone who can help- I would go back to longeing. I donít like to ride a horse until they can do it without a person on their back. Putting in some time with him cantering on the longe, until he is strong enough to hold it and is cantering really solidly can help prevent some of the flailing I see unconditioned horses do. Riding a flail is not fun and can be hard to focus on improving.
And for the inexperienced rider, they just donít have the capability to ride the canter enough to fix it.
I start with Longeing without sidereins until the he figures out the canter and builds some muscle- 1/2 weeks. And then add side reins to help shape the balance better.
You can then climb on to work on w/t, but give it a few weeks for him to build muscle memory on how the canter should feel and to strengthen his back and stifles.
This. THIS THIS THIS! Why do from the saddle what doing from the ground will be better? Horses need consistency. If you are not solid on even knowing how to correct the issues at hand, you need to extract yourself from the equation.
So, to me, all of this is rider fault. Two of your horses having a left lead issue is a red flag, as most horses aren't that similar. That means your right side is the weaker side when riding, most likely
. I have no photos or videos, so I don't know for sure.
His leaning in on the shoulder is probably from you leaning your shoulder in to get the lead and then staying there in an attempt to keep it. You aren't doing it on purpose, but with green horses these sorts of mistakes make differences. Anything your body does influences their body.
How is your brain through all of this, as well? Are you thinking 'we have to keep the lead, why is he speeding up, why is he slowing down, we won't be able to make that turn?' Or are you thinking, 'ride straight, keep my leg, allow what happens to happen then correct it kindly and explain the situation.' ? Horses like this need calm, simple answers and just a small amount of work. If he does one corner well, pat and be done on the issue! You are here to build his
confidence, not yours in your ability to retrain a horse. That is how you should approach every ride.
And trust me, a lot of this you're doing subconsciously - I think we all do when we work with our first few greenies!
Secondly, the 'endless circles' are a good thing. Your trainer seems to be wanting you to take the time to allow Teddy to figure himself out. With inexperienced horses, a lot of it is letting them to figure themselves out until you can start to mold the correct things they do into aids. He's going to be fast and slow and discombobulated for a bit - he isn't sure where to put his feet along with your weight. LET HIM! Unless it is a danger to you or him, let him make mistakes, especially if they make him uncomfortable.
When teaching hunters lead changes, if they don't give it to us or give us a half hearted one and only swap in front, we still canter on to the next jump and make them jump it. Horse will put together that 'oh wow that was uncomfortable and obviously the wrong answer to the question I was just asked' and try something different.
That 'different' may be a huge buck, but you keep on going until they do the right thing, praise them heavily and be done for the day. The next day if they do it right, you do it again. Build on the foundation, not the action.
I'd highly suggest lunging if you are highly capable. I mean knowing how to fit side reins without asking online, knowing how to drive forward and whoa and hold everything without getting tangled or looking down.
If not, I'd really work on this with a trainer more.
I apologize if this comes off offensive, but coming to an online forum isn't great or even close to equal to training advice, especially with no videos. You need a trainer there more than you have one currently, especially if you're this inexperienced with green horses. I don't want anyone getting injured or hurt - horses like this are more prone to injury as they aren't really thinking great for themselves yet.
As an aside - I'd HIGHLY HIGHLY recommend you open your reading pool and start studying up if this is something you continue to pursue. Paul Belasik has amazing books. I'd suggest Nature Nurture and Horsemanship first and then go from there.