I do not train changes with a pole on the ground because I believe it teaches horses to swap leads in a flat fashion rather that get nice, jumpy dressage changes. However, Wheels is a special case, so I'm willing to try anything. Last year, Pam suggested using a pole between circles. Canter a circle, change direction over the pole, back and forth. I tried this, but he had the tendency to chip the pole and land on the wrong lead anyway. Dork. Sometimes it would work, but it wasn't consistent. I didn't try again finding it added confusion.
Wheels is much stronger now and has a pretty good simple change (at least over the last few days). I thought I'd try the pole again. Oh dear. That's not a pole, that's a 4 foot oxer...and I'm in a very unforgiving County Perfection! However, he landed on the new lead. OK. Hike my stirrups up as far as my saddle will allow and stay in a light seat. Back and forth over the pole, leap the pole onto the new lead, leap back, back and forth. Wheels thought this was a fantastic idea. I would creep further and further to the ends of the pole until the pole was no longer under his feet in the change from left to right (the direction we tend to have the most success with the changes). Boom! He got the change without the pole. I immediately made a huge fuss and put him away. You could see Wheels' brain turning.
The next day, I brought him out like normal. We warmed up like we always do and he felt bright and fresh. Up we went to canter. Cantering along, happy, starting to put him together, shortening my reins, I put my outside leg back a little to ask him to leg yield into my receiving hand (my outside leg, remember). All of a sudden, Wheels begins launching in the air, legs going every which way, but happy expression. Hmmmm? What the heck? Ok, back to canter. Start to turn, launch around, legs everywhere. Wheels, what are you doing? Let's just trot, OK? Sure, Mom, what do you want to do? Half-pass, shoulder-in, big trot...no problem. Canter again, but let's go the other way. OK. Can you go sideways? Launch in the air, legs everywhere, body heaving over the ground. "Wheels, we're not going to work on changes today." "Oh, sorry, I thought I was doing them. Nevermind." And off he went to work. Fool.