Originally Posted by MIEventer
What are you doing with your lower leg when you are riding? Where are your feet? And are you gripping or pinching with your knee's?
Also, where is your hand position?
That's my first thought too. Your lower leg is your FOUNDATION! You have no real balance or security without a good lower leg. Your heel should be directly under your hip. Your leg should have equal contact through your thigh/knee/calf (not more pressure in one of those three areas). Make sure the INSIDE of your leg is what has contact with your horse's side, not the back. Start with a good leg first, and other parts of your position/balance will come.