So, Rule #1 is to be safe while around a horse. To be safe right from the start means that you need the help of an experienced horseperson, and not one who's advice could get you killed. Let me give you a glaring example, taken right out of the Parelli News weekly e-newsletter...
Every newsletter features a question and answer section, presumably from a Parelli "student" to Pat or Linda Parelli. This example is overflowing with the Parelli lingo that always draws the person trying to learn horsemanship away from common sense and into insanity.
I got my very first horse last November. She was a rescue horse from the Humane Society, taken away from her owners because of abuse. Her name is now Mia, and she is a red roan Tennessee Walker with a very difficult Horsenality. She can switch very quickly from Left-Brain Introvert to Right-Brain Introvert. This last weekend, I went out to her stables to ride her. I played a few games on the ground with her before I rode her. She seemed fine, wasn't tense and she was focused on me. When I went to ride her she seemed fine and I couldn't feel tension in her body or anything. The only thing that I noticed was that she wanted to go faster. Usually I would love to go faster, but since it was her wanting to go and not me, I held her to a walk. Then all of a sudden, when I finally asked her to trot she reared twice! She has never done this before. So I got off and checked her feet and checked to see if anything from the saddle pad was sticking her. I couldn't find anything, so I got back on and tried it again. I did the same thing, held her to a walk when she wanted to go and then asked her for a trot. But she reared again. We checked everything again and I got back on (kind of stupid). This time when I asked her for a trot she seemed fine and so I took her down in the lower paddock. When I got down there, I asked for a canter and she freaked out on me! It was all of a sudden, she got tense and started rearing and bucking and kicking all at once. I managed to stay in my saddle, but got off after that one. I couldn't find anything that could be spooking her. Is she testing me to see if I'm in charge? Could she just be wanting to go? —JM
Dear oh dear, I'm glad you're okay! What you're describing is mounting panic and the main reason it built is because you held her back. Imagine yourself in her shoes.. you're wanting to go faster because you are a bit scared about being out there and feeling vulnerable to predators, think lurking LIONS! And now you're being held back and you just know when the lions will be nipping at your heels and your escape door is shut. Little by little the terror mounts and it's hardest to feel it in introverts. They seem to be handling it, that tension doesn't feel that bad, but then it all gets too much to bear and they explode. Even though she exploded once you got home, it's where the pressure was released but not where it occurred. Think about building her confidence at home with longer lines and creative extreme Friendly Games. When you do go on the trail pay attention to thresholds and do what it takes to overcome them. Finally, don't hold her back if all of a sudden she has trouble. Get off and direct that energy until she is calm. When prey animals get on adrenaline they need to move their feet in order to get it out of their system. Look to both the Right-Brain Introvert and Right-Brain Extrovert strategies to know what to do.
The Lone Ranger be damned, because the absolutely most dangerous behavior a horse can give a human is rearing, whether that person is standing on the ground or on the horse's back. Rearing is the severest show of aggression that a horse can do. Trainers, very experienced and real trainers won't bother wasting their time - or putting themselves at risk - to work with a horse that rears.
So, the answer that should have been given to this girl with no ability to handle such a problem horse follows. This is from an experienced horsewoman with years of training, riding and showing under her belt:
Lady, are you NUTS? For sure the horse is! Who knows what poor training (if any) a horse coming from that sort of background has had. The first thing you did wrong was buy a horse from a "rescue." They aren't "unwanted" horses without reason you know. Second mistake you're making is to think that with your lack of experience that you can safely (keyword safely) train this horse yourself, which your story has just now proved beyond doubt.
Either send Hi Ho Silver to a professional horse trainer for 3-6 months at $500 a month and HOPE you get something safe to use back, or shitcan the piece of shit and spend the $1,500-3,000 you would have spent on training on a GOOD LEGITIMATE horse that wont fall on you and cause you to admire horses from your wheelchair for the rest of your life (if you're lucky) THE END.
Like I said, there's a big, big difference between dreaming and reality when it comes to horses. I'm all for everyone owning one that wants one, but at least have the common sense to learn about horses before you buy. Most of all, be a bit more discriminating in who's advice you take -- before it kills you.
Update: March 17, 2012
Noting how popular this post is, visited by many around the world concerned that TV horse trainers may not be the best source of information, I felt it important to update. Today, I found an excellent article by Linda Parelli that outlines very good ways to keep yourself safe so that you can enjoy your horse: