… third leg and zhong ding practice.
Zhong ding, or central equilibrium, is a pivotal aspect of tai chi practice. A few years ago, George Xu incorporated the concept of “third leg” to describe zhong ding in motion. The concept of third leg helps to refine the movement by focusing on a point from which to move and how to move. Biomechanically, the motion pivots at a leverage point inside the hip assembly at the base of the spine. The femur and sacrum are connected in motion if not physically. This is from where you pivot and turn. Everywhere else is “loose, open” as Master Xu says.
Weighted in gravity is another concept to help incorporate the third leg in movement. You let the body’s gravity rest on the leverage point while moving. You feel your body’s weight sit there like a rock would on the ground.
Susan A. Matthews’ “Backwards Bicycle” motion (learn more) that she describes is another good application of zhong ding biomechanics. While it may sound simple, incorporating it in practice is a little awkward at first try, especially for unpracticed individuals.
Mind intention is necessary to refine the zhong ding movement, utilizing third leg and backwards bicycle. The mind directs the flow of energy in circle motions, figure eights, or spirals. The body wants to move in these configurations and the mind’s job is to allow it, intending the result, then enjoy the ride while directing it in those shapes and patterns.
No hard corners. Continual focus on movement or the sensation of motion, or flow. Spiraling motion results. Matthews described it once as two cones whose tips are touching and the circling is moving in a figure eight around the outer edge of the cone. You have two points: one fulcrum and the outer circling or waving action. They are always connected, no letting up, no pushing down; just weighted in gravity and in motion. This works well, but when you add the third leg to it, you have an added power-generating activity. More stable and refined. While learning and practicing, I find it fun to focus on incorporating these techniques into the form or basics.