For safety reasons - learning how to stop a horse is the first thing you need to learn when horse riding. To the untrained eye it might just look like the rider pulls the reins towards them and releases when the horse has stopped. However there is more that goes into it. Here are the 3 simple steps every rider should do when stopping a horse.
1) Half Halt
A half halt is when you gently squeeze the reins and your thighs in a split second for your horse to become more alert to your aids and to sit back on its hind legs more. Half halts keeps the horse alert and balances your horse - making it easy for it to prepare for the coming stop.
2) Sit down heavy in the saddle
The first step is to prepare the horse to stop by sitting heavy in the saddle and squeezing your core and inner thigh muscles. These weight aids will help to slow the horse down.
The third step is to use a verbal cue (especially with young horses). The verbal cue should be established and taught to the horse on the ground first (usually lunge line). So once you're on the horse riding, the horse knows exactly what the cue means. A horse trainer will usually use the sound "whoooooa".
4) Squeeze the reins gently
The first aid it to apply gentle rein pressure as this will make the horse come to a complete stop. The best way is to already have shorter reins with contact to the horse’s mouth. You won't have to use your arms much then and can become 'one' with the horse’s movement.
5) Release the reins as soon as the horse stops
Horse's learn by pressure and release training, so it is very important that you give the horse the rewarding release as soon as it listens to your cue.
Give the horse a more loose rein as soon as it stops. The rein aids may not be needed on an experienced horse as they tend to listen to the weight aids only.
This is a different scenario as stopping a bucking horse needs stronger aids. A frightened horse will not listen to subtle cues. So in any emergency situation a one rein stop is a great stop to use as an emergency brake. For both the riders and horse’s safety this should be practiced on the ground before getting on the horse’s back.
A one rein stop involves the rider grabbing one rein with both hands and forcing the horse’s nose to touch your leg and on a tight circle. This restricts the horse from any forward movement. This will prevent any undesirable behavior such as making the horse bolt. Remember that horses are a prey animal and can learn bad habits if frightened. Therefore only a experienced horse owner should take on a young or nervous horse in a training program.
The most common reasons for horses bolting or bucking is that they are frightened or have a poor saddle fit which is pinching the horse’s spine. So its important to make sure that there is no underlying cause to your horse's behavior.