With regard to posting diagonals, Elizabeth wrote,
"I would like this one clarified as well. I normally post so that I am standing when the inside leg hits the ground going around a curve. This is opposite of what sherman wrote, so I would be interested in hearing rationale for each one."
During ring work, the reason to sit when the inside hind leg is on the ground is because it is easier to apply the aids when sitting rather than when rising. The inside hind leg is the one we usually want to influence.
When trotting down the trail, it is important to change diagonals often to promote symmetrical muscle development in both horse and rider. That said, try to spend more time on the diagonal with the hind leg you wish to influence the most. For my horse, that is the right diagonal, which means that I will be sitting with the left (lazier) hind leg. That way, my left leg is in position and ready to apply a gentle reminder to my horse to drive his left hind under his body and push with more energy. Otherwise, he would be content to let his right hind carry him through the entire 50 mile ride.
