My arab mare used to crowhop every time we ran (and still does whenever we are in the indoor arena) but has gotten so much better. I ride her mostly bareback now & we run all the time. She had very poor ground manners, though and NO patience! She would NOT stand still to be brushed & saddled, would pull back sometimes when bridling and always had her attention on anything but me, whether on the ground or in the saddle. It was SUCH a pain!
I lived with her for 2 years like this and then started NH. Now it takes literally less than 5 minutes of just doing some of the ground exercises, especially circling and backing up and I can leave her groundtied to saddle & bridle & don't even need to ride her in a bridle anymore!
I see more sense in this than others who run their horses in mindless circles for long periods of time trying to get rid of the horse's excess energy. If the horse's mind is engaged, it won't matter how long he's sat in pasture or what breed he is. He will listen to you because you are the leader.
Also (just to point it out) basic longing just stimulates and increases the horse's flight instinct because all you're doing is chasing the horse around. This CANNOT build a horse's respect or confidence in you as a leader, just convince it that you are a predator).