I just caught part of
this dicussion and hopefully can help some here. First of all, I couldn't
imagine riding a sitting trot for miles. What good can that be for
the horse? Anyhow, when I teach rising trot, I say it's a more up and over
the horse's neck movement. You post into your hands with your
abdomen. A pelvic thrust of sorts, if you will. It is not an up and
down motion only; it's forward and up. When you sit, you try to lightly
touch the saddle, not thump down. You wait for horse to push you up.
Most people work way too hard at this. Breathe, center and let it
happen. I have taught my guys to slow down with just my breath.
Another thing when you are really moving along is to get in a two point
position. The big thing with all of these things is to make sure your legs
and feet are underneath you. If your stirrups are too long or set too far
forward, you will brace with your legs and your balance (yes, there is bad
balance) will be lost. You need to have a bend in your knee so your joints
can work like they are supposed to. Try not to hollow your back like the
hunt seat equitation riders do; that can hurt you. The spine was not
designed to work like that. Well, I hope this helps. There is no
substitute for good riding to keep your horses sound.