Horse rearing during reverse of direction

I recently rescued a 7 yr old Arab mare that was pretty green. The handling that had been done with her wasn’t a positive so she has some fear issues. I have all of your DVD’s and am wondering how to deal with a specific issue. I realize you are very busy and I would understand if you aren’t able to answer. When lunging on the ground, when I ask her to reverse directions, the will rear up and then walk off. How can I stop the rearing? Thank you for taking the time to read this : ) God Bless

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