I clucked. He shook his head, side to side, and curled up his neck. He put his ears up straight, not back, but straight up as if to say, “I will be mad at you if you keep pushing me.”
I clucked again and lifted the lunge line hand with the extra loops, not to swing it at him or intimidate him, but to see what the pressure might produce.
We did not get much more than the first response, (the head shake and warning arch) but he wanted to stop trotting around the circle and he was trying to let me know he recognized that it looked like work and he wasn’t sure he wanted that. So just to make sure he knew I was not going to give in at the slightest sign, I made him go around one or two more times, then we stopped and finished for the day.
My first thought was, oh, they raced you when you hurt. Because that is why horses show sourness or reluctance — because they have learned if they try, it will hurt. If you unravel the why of behavior it is the first step to changing it.