To answer this question we go back to the foundation of dressage. The incentive to develop the dressage was fighting on horsesback.

With a sword or lance the rider had to be able to maneuver quickly so the horse had to be strong and supple.

When riding around an opponent the rider would use shoulder-in on a circle. In this video a rider rides around a pillar that is a kind of  replacement for an opponent:

The quarter-in movements were very important and a ‘must’ in duels, because the sword was given as much space as possible without touching or hurting the head and neck of the horse.

In the maneuver ‘quarter-in’ the rider has to sit also more on the inside seat bone because again the rider leans against his opponent:

1. Firstly to approach him as closely as possible.

2. Secondly the ‘inside seat’ increases the range of the sword considerably.

3. Another advantage is that it teaches the horse to always step under the weight and the point of mass of the rider with his hind legs. Thanks to this support of the hind legs the impact of the sword will be much bigger. The opponent can feel the push of the hind legs when he has been hit by the sword.

4. And the rider will not fall backward out of the saddle because of the impact of the sword of the opponent. This will happen much easier if the rider would sit on the outside.

So in all side movements we use the so called ‘inside’ seat.

MOST pets are left or right “handed” and prefer to use one paw, foot, eye or even antenna over the other, scientists have discovered.

The finding dispels long-held assumptions that only humans had evolved to do this and that all animals were ambidextrous.

But being left or right-handed, called lateralization, has now been shown to be present in nearly every creature.

Tests on cats and dogs revealed that, like humans, they prefer to use either their right or left paw.

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