There’s nothing more distracting than a horse that frequently throws his head up in the air, dragging the reins through his rider’s hands. A horse that constantly tosses his head has one of a few things going on. He might have a dental issue and the bit could be irritating him and making him feel uncomfortable. Before you do anything else, you should have his teeth looked at by an equine dentist and get any issues fixed.
After you’ve ruled out a dental issue, you’re looking at one of three possible causes the first of which is being a heavy-handed rider. Oftentimes, riders with horses that root against the bit and fling their heads up in the air are guilty of constantly hanging onto the horse’s mouth with two hands, never giving the horse a release of pressure. In an attempt to get the rider to loosen up their hold, the horse develops the habit of tossing his head to drag the reins through the rider’s hands. Remember, horses learn from the release of pressure, not the pressure itself. Our horses dream of us not pulling on their faces. So if you’re constantly holding onto your horse’s face, he may be rooting his nose out and tossing his head in the air in an attempt to get a relief from the pressure and reward himself.
Now I don’t want you to confuse “hanging onto the reins” with picking up on both reins and asking the horse to give vertically. Even though you’re holding onto the reins with two hands when asking the horse to collect and soften to the pressure, you’re constantly giving back to him (releasing the pressure) and rewarding him for softening to the pressure. What I’m warning against is holding a dead-pull against the horse’s mouth and never rewarding him for softening to the pressure.
Kids’ horses are really good at developing the habit of rooting their noses out and tossing their heads. They get the jack of the kid pulling back on the reins, so they root their noses out, dragging the reins through the kid’s hands to get away from the pressure. Some of them get so violent about flipping their noses out that they practically pull the kid out of the saddle.