IAnyone can train a reinhorse. Yep, they can do a good stop(bouncing off the front legs and jarring to a stop) doing a spin(which consists of walking in a circle with their whole body) doing rollbacks(turning on the forehand) doing impressive circles(run as fast as you can both ways and don't forget the beautiful lead changes in the middle)and of course the long sliding stop(with the mouth hanging open and the head thrown up to get away from the pain in the mouth from the yanking bit)
No, the truth is, a true reining horse is a sight to behold. The beauty and grace of the movements are intricate and cues are unseen. The horse just seems to float through everything and their head is tucked and soft and supple. An awesome sliding stop of 10 or more feet with the horses head dropped, the front legs moving with the slide and the back legs still and supporting the body is something to watch if done correctly.
A book will not show you how to teach your horse to rein. You need an experienced trainer to help you and expect to spend hours teaching your horse to be soft and supple to be able to even start making the flowing motions of reining. If your horse is freezing up, then he had no clue what you are asking of him. To just expect to make a horse spin or slide to a stop without the proper training is not going to happen, instead it will make your horse fight the cues.
My mare has had reining training and I had someone help me work her. Nothing fancy, but she does beautiful stops,rollbacks and does nice spins, but I did not have a clue how to ask her for them. Now I do and we have fun playing
But by no means are we past "having fun". But I guarantee she does not freeze up or open her mouth when asked to do these things.
A well trained reining horse is as beautiful to watch as a well trained dressage horse. It is a partnership between horse and rider, not a contest of wills.