Hi there! I'm new here but I'm an old DQ
. I'll be frank and to the point about what I see here.
Cinny is moving front to back, not back to front. This is caused by the extremely tight sidereins, as in one foot too tight. They have caused him to curl up in a ball to avoid contact, and he is punished by the sidereins with a jab in the mouth each time he tries to uncurl. He is heavy on the forehand here-I haven't seen other videos so I don't know your history. Sometimes that's best for clarity
. The loading of the forehand is caused by the lack of impulsion and the tight sidereins.
I just want to totally loosen the SRs, put him on a huge (3x bigger) circle, and send him forward.
I'm sorry your trainer believes this is the correct frame to develop the back
.I assure you it is not, and you are doing your horse no favors here.
Again, I don't know your level of expertise and I apologize if my bluntness offends. Engagement comes from forward first and foremost.
Move the engine (hindquarters) and the horse learns to engage and lift the shoulder, lightening the forehand. Add steady contact and voila-horse comes onto the bit. (Obviously oversimplified, but you get the picture).
With the SRs so short, all you will get, all Cinny will get, is punishment when you ask him to go forward. Study the vid where he starts to power forward and lifts his neck(yes, AND his head...that's OK
) and gets popped in the mouth for his effort and drops back to a shuffle. The only moments where he even approaches having his poll as the highest point and head on the vertical are those surging steps. And he gets nailed.
You spoke of contact issues in your OP. He is a curler, yes? The way to "fix" a BTV curling contact evader is FORWARD. AND LEAVE THE MOUTH ALONE. provide light steady contact,and if he curls, send him strongly forward. REPEAT AD INFINITUM. You