I don't know it this will be helpful but here goes:
It's hard to imagine the concept of deepening your seat at the
posting trot. While schooling TBs right off the
track and I've found that by slowing, just a fraction, my posting
trot I can moderate their gait. I try to slow the post slightly,
while sinking more deeply into the seat and imagining
that I'm posting toward my knee during the upward post motion. This
minimizes the motion of the post.
It sounds like you probably need to work on these things in the
controlled environment of a schooling ring where you can both work on
the transitions with minimal distractions. The horse should not be
breaking from the trot as soon as you sit. Since you know he tends
to do this, anticipate his behaviour by closing your legs and
dropping your weight into the seat, while gently using repeated half
halts, until he settles into a sitting trot. It seems that he
resents you taking "hold" so you probably need to be very supple when
asking for the down transition, resisting the temptation of bracing
your shoulders and arms. Perhaps imagining that your hands are
floating on water will help you relax your arms. Once you've got the
horse yielding in the ring you may have more luck out on the trails.
Beth Glace, M.S.
Sports Nutritionist
lb@nismat.org
Events