So, I am not discounting there may be something physically at play here (and also recognize my input might be unpopular), however…
I read your entire post several times. There are multiple mentions of tried and failed diagnostics, restarting ridden work after those diagnostics or treatments, and each time is the same word: forward. Get the horse more forward, push him forward, keep working on fitness via getting him forward, etc.
You also mention from the moment he arrived that he did not accept the bit: all the symptoms you describe, the rooting, taking over, “framing up” without it coming from behind, are all symptoms of a horse who does not understand what the bit means. These signs, however, seem to have been dismissed as due to a lack of fitness, as have a number of his symptoms.
The combination of those two things lead me to believe the following:
- This horse has no idea what the bit means, how to respond to it or how he needs to relate to it. He has been constantly trying to push it out of the way, literally, for months now. Continuing to expect that he learns to accept it using the training paradigm you have been adhering to has caused him more and more angst and increased his desire to make it go away.
- This desire to make the bit go away leads to him being heavier and heavier on the forehand which means it’s going to be virtually impossible to condition his body properly. More tripping, more unhappy in the bridle, heavier in the hand, more miserable to ride. On top of that, the advice you’re being given is to get a horse that is already tripping and already heavy MORE forward? Heavy on forehand + asking for more forward = heavier on the forehand.
- The stifles: IME, a pretty classic side affect of a tight back. A horse who cannot or will not lift freely through his back creates the potential for the physical mechanism that allows range of motion in the stifle to get delayed/out of time with the stride, which causes the popping/slipping. And yes, it’s quite disconcerting to the horse: he’s lost his balance, literally lost a leg out from underneath him. It often isn’t actually that uncomfortable but it gooses them and for a prey animal that depends on being able to run away to survive, that’s scary.
You’ve literally addressed everything you can think of except one thing: his thoughts. His brain. How he feels about and relates to the bit, to being ridden. And the worsening of his symptoms, from that viewpoint, makes total sense. He didn’t have the understanding to begin with and continues to tell you he doesn’t have that understanding and yet he continues to be asked to work, sometimes adding more work(!) (adding canter, for example, when he was still miserable at the walk and trot…) on top of things he’s already struggling with. If the horse is struggling with something at the walk, you address it at the walk. Adding increased need for balance by moving into the trot and canter is going to exacerbate the issue.
I’ve owned a lemon horse. I am not saying this from a place lacking empathy. But what I learned with my mare has informed how I think about every horse that has come after her. You can scan any horse and eventually find something, especially a horse the age of your gelding.
I give you kudos for going the lengths you have to figure him out, but I honestly read your post - again, multiple times - and kept coming back to just plain lack of education couple with having not used his body correctly for a long time. A horse does not need fitness to be able to learn how to soften to the bit, nor does he need fitness or conditioning to be able to carry a soft feel in the reins for a few moments. You build these things over time, but the horse doesn’t need a ton of fitness to offer it in small pieces. This is where I would have started from the get-go, but it’s not too late for you to start now.
Again, no judgment here. I have been there, done that, bought the t-shirt and worn holes in it. I get it. You’ve gone through every avenue and recommendation and taken every piece of advice to heart to try and get this gelding well. But it seems you’ve listened to everyone except for him. He told you what his issue was from the get-go, the first thing you mentioned in your OP: his struggle relating to the bit.
I’d take a furlough from your dressage trainers. Take the gadgets and head-setting devices off him. Stop asking him to do any more than WALK until he can demonstrate that he will. not. push. on. your. hands. Ever. Ask him to start taking responsibility for his own balance instead of making you do it for him. Ask him to start to learn to work in a way that eliminates all the problems you’ve described here because you’re teaching him how to carry himself without leaning. He does not need fitness to start to learn this. It may take a good while longer for him to get confident and convinced that this is how it is, but he does not need a high degree of fitness initially.
I could try and walk you through how to achieve this in this thread but to be honest I feel like you need in-person support, someone who knows what they are doing and can guide you in real time. I’m happy to get into details here if you think it will help, or you’re welcome to PM me and I can see if I know of someone down your way who might be able to help as I’m in VT so you’re too far for me.
