Ground-driving has been a successful training technique for centuries, and in a wide variety of disciplines. For instance, trainers at the famous Spanish Riding School in Vienna rely on ground-driving to teach their Lipizzaner stallions essential lessons on their way to advanced dressage.
Ground-driving pays many dividends later on the trail, even for the horse never destined to pull a buggy. The colt mentioned above, a Belgian/Tennessee Walking Horse cross (ironically named Trouble), was slated to become an all-purpose horse for riding, packing, and harness work. But every horse I train, including those destined for saddle alone, experiences being driven and signaled from behind.
What Driving Teaches
Ground-driving is one of the best ways to teach "whoa" and "back," to teach a youngster to listen for your signals, and to turn right and left with subtle rein pressure. All this can be done before he's mature enough to carry a rider.
A young horse thoroughly trained to ground-drive is often a safer animal when the time arrives for that first ride. He already thoroughly knows the basics of impulsion and direction, and he's been taught a positive "whoa." He's become entirely used to long reins rubbing his rear, to sounds behind him, to the slapping of stirrup leather and the press of the cinch as he moves.
Ground-driving is also an ideal way to teach a young horse to carry weight long before a rider mounts him, particularly if you use a pack saddle for the purpose. I'm far more confident mounting a colt for the first time if he's already experienced carrying weight on his back. My favorite load for a young animal is 100 pounds of feed or granulated salt, one 50-pound sack on each side, enclosed in cloth panniers.
Ground-driving comes after several sessions accustoming the youngster to my usual routine. I curry, rub with a blanket, pass ropes over his body, pick up his feet, and teach him to lead by each foot.
Many methods work, and any gentle-but-firm routine for starting a young horse will ready him for ground-driving, with a couple of caveats. Impulsion must be taught, whether with signals from a longe whip or the long lead rope commonly favored today.
Too many inexperienced trainers aren't assertive enough when teaching impulsion. If a spank on the rear is required to send your horse forward, use it: training can't progress without your horse understanding impulsion.
Much training today centers on having the horse face the trainer. But taken too far, this can cause problems for the driving horse. I once worked with a very large, very nervous Thoroughbred/Belgian cross that had been trained, probably with some severity, to face the trainer above all else, to never turn his rear toward the person in the round pen. Thus, his answer to every insecure moment was to whirl and face me. Training him to drive, to tolerate my presence behind him, stressed the limits of my patience and nerve.