I'm getting my horse a massage?

Rusty is getting his first massage tonight. Actually, equine myofacial release would be the proper terminology. I'm hoping for some answers to his resistance in moving forward. I worked him on Sunday and was able to identify that he seems to come up short in his left hind leg when transitioning down from the canter to the trot. He remains off for about a quarter to half circle and then appears normal again.

I jumped on him bareback briefly on Sunday to try my voice only, no whip commands to see if he might relax into some nice transitions. No luck, he was absolutely against it. He was threatning to rear and buck and actually completly stopping movement. I had one of my barn friends come into the round pen and pick up the lunge whip, at which point we had beautiful transitions. As soon as he left the round pen Rusty immediatly began his routine of refusing to move. So I asked my new assistant to come back in and pick up the whip again. Again transitions were back to perfect. We worked like this for a couple of transitions, than my assistant dropped the lunge whip and remained in the round pen, transitions remained nice and slowly the assistant left the round pen and we were able to continue with a few more nice transitions walk-trot-walk. So I called it quits. I suppose that's forward progress and I'm aiming to do a couple more of those works this week where there is support given by lunge whip at times to reinforce.

We'll also evaluate his body tonight just to see if there is a pain cause for all of this behavior. I suppose both of these give me a glimmer of hope for now...