They only know one use of the legs, that is to grip the saddle so as to keep their seats in it.
The “High School” rider uses his legs for giving the indications to his horse of what he wants it to do, supplemented by the reins, which, by more or less pressure on the mouth and against the horse’s neck, indicate the horseman’s wishes to the horse.
A “horseman” does not pull at one rein to turn the horse any more than an expert cyclist turns the handle bars when he wants to turn a corner.
The cyclist leans to the side he wants to turn to and comes round like a pair of compasses do when you lean them over and let the pencil swing round.
If a “horseman” wants to open a gate he does not kick his heels into the horse and thus force him up to the gate and then lean over the horse’s neck to try and reach the gate, which the horse is backing from. The “horseman” holding his reins in his left hand, squeezes the horse with the calves of his legs and this makes the horse go forward.
As he gets to the gate the “horseman” puts his left calf further back against the horse’s left side, at the same time putting his left hand slightly to the left so that the right rein presses against the horse’s neck.
This turns the horse’s neck and shoulders to the left whilst the pressure of the left calf against the horse’s left side makes him put his right hind quarters to the right. The horse now stands broadside up against the gate and the “horseman” can easily use his right hand on the gate lock, without having to lean over.
When he has taken hold of the gate a slightly greater pressure of his right calf whilst tightening the reins makes the horse’s back and quarter turn, and the gate is opened. He eases his horse’s mouth, squeezes with both calves, and the horse walks through the open gate whilst the gate closes behind him.
Suppose two equally good pistol shots, one a good “rider” and the other a good “horseman” are in a mounted pistol competition.
They are told to walk their horses past the target and shoot at it one shot out of their automatic pistol as they pass. Both of the horses have not seen the target before and are rather shy of it.