For some horse people, the age-old term "breaking" a horse is politically incorrect. They prefer less violent terms such as "starting" or "backing" an equine. No matter the terminology, it boils down to correctly training a young horse for riding. Trainer John Strassburger, former editor of the Chronicle of the Horse, prefers the term "starting under saddle," because the aim is to have the young horse work with the rider.
Long before he has a saddle on his back, a horse must learn basic ground manners. This includes learning to lead, cross-tie and stand for the farrier. You get the young horse used to grooming, bathing and the application of fly spray. If possible, teach him to load and travel safely in the trailer. You're aiming to make him a solid equine citizen, which benefits both of you when actual under-saddle training starts. With horses, it's important to remember that every experience you have with them is training in one way or another, good or bad.
The Right Age
Although racehorses start much younger, the best age to start breaking a horse to ride is between the ages of 3 and 4. By that point, the horse's skeletal structure has matured so that he can carry a rider without compromising him physically. He's also more mentally ready to learn. Before starting him under saddle, work to establish basic fitness. That includes ponying him with an older, well-trained horse -- leading the young equine while you're riding the experienced animal. You also can teach him to lunge and ground drive before getting on his back. With these exercises, he's also learning voice commands.
Getting Used to the Saddle
If you're lunging or ground-driving the horse, he's already used to a mild bit. Spend a few days putting a saddle on -- making sure it fits the horse correctly -- and taking it off again. When the horse is used to the saddle and bridle, lunge him with all of the tack on. Continue this practice for several days, sliding the stirrups down at some point so the horse gets used to the feel of them on his sides. Once he's comfortable with the whole process, it's time to back him. You'll need some assistance.
Backing the Horse
Ideally, at least three people are in attendance the first few times a horse is ridden. There's the rider, a person who can hold the horse, and someone to help the rider mount. Initially, the rider just lays across the saddle, getting off after a minute or two if the horse behaves. The next step involves the rider swinging his leg over the horse, so he is actually sitting in the saddle. If all goes well, that's enough for the first day. Over the next few days, the rider mounts and another person lunges the horse. In brief schooling sessions, the horse learns to walk, trot and halt on the lunge line, responding to the rider's hands, aids and voice commands. Once the horse does well on the lunge line, take him off and start riding him in a safe, enclosed arena.