I went as far back as I could to find his comfort zone. I walked him aimlessly around the perimeter of the arena allowing him to stop and gawk at whatever caught his eye. He was very relaxed. I asked for a very loose-reined trot which he gave me happily. We did a long series of movements that he seems to enjoy: trot around the dressage court in both directions, changes of direction across the diagonal, three loop serpentines in both directions, 20 meter circle in both directions, and a canter circle on first the left lead and then the right. I do all of this on the loosest rein possible.
When he did all of this, I let him walk and praised him enthusiastically. As soon as I picked up the rein to get back to work, his back hollowed and his head shot into the air. He tried to break into a trot, but I gave him a gentle whoa and insisted that he walk. I had to do this several times. Since it was the trotting that seemed to generate the tension, I shortened the reins and asked for the bend that I wanted while at the walk. We had done this a lot over the summer so I hoped he would remember that it's not scary or hard. In a fairly short time, his neck was again supple and he was moving away from my inside leg in both directions.
When I was fairly confident that he was genuinely relaxed, I asked for a trot from that same rein length. He gave it to me fairly willingly. In fact I was able to very gently shorten the reins even a little bit more. I discovered that I have to be very subtle while I do this. If I drop the connection at all while I am shortening, he becomes very tense when I try to re-estabish the connection. This is clearly a rider error; I will be working on my technique.
After just a few times around the circle with a long and low frame. I asked for a halt and praised him generously. We changed direction and worked the other way. It took a few moments to get the same connection, but the panicked tension from the day before was gone. Again, after twice around in a long and low frame, I halted and let him know that he done a lovely job. I hopped off and gave him a big face scratch.
So, what did I learn? Sydney can do this, but he needs to warm up to it very slowly. I may not be able to do much trot work in the afternoons after work. There simply may not be enough daylight hours. Once the time changes, we may only do the long and low walking with the free trotting. It might be that the weekends will be when we do the real work. I'll have to wait and see.