If everything pain related has been checked out and he doesn't do it with other riders it may just be you. I'm not saying you are a bad rider, maybe he has created that habit from any emotion conveying from you to him when you're ready to go in the arena..it can be from you being anxious, nervous, excited, unsure..all of those emotions can tense up your body and that can transfer to Radar, especially now that it has become a habit. You are expecting it, so is he, and when it happens you both get frustrated which just makes it worse...I suggest setting up or going to an arena and just walking in and out of it like you would at a show. Take him to a show and don't actually compete. Just get there and let him be in that setting, walk around, go into the arena, but let yourself and him just chill out in that setting without putting stress on you both.. This can happen very easily with barrel horses also and the longer the habit is allowed the harder it is going to be to retrain him and change that mindset..
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