If I think about my legs, I forget I have hands. When I concentrate on the reins, I tense my shoulders. It means riding through fear, not letting the fear stiffen one's body or one's resolve. Fear arises when the horse stumbles, when he bucks at the pressure of the legs, when another horse comes too close and his ears flatten on his head. When fear overwhelms me, having a good seat literally becomes impossible.
Riding is about getting out of one's own way, and getting out of the horse's way as well.
When I am riding in harmony with my horse, the energy is able to flow freely. In those few fleeting moments when I am able to be present with this, I can handle whatever obstacle might come our way. This understanding actually goes back to the old technique of riding a horse. When you have a rider and you have a horse, then you begin to realize how to hold your seat, how to hold yourself on your saddle. If you have a bad seat, you can't connect heaven and earth.