Chen Xiaowang says that peng jin is like revving the engine of a car. If you lift the car off the ground and rev the engine, the car goes nowhere. Put it down so that it connects to the ground and it has power.
Establishing the ground path is a skill I learned from a two or three people I respect in the internal arts -- Mike Sigman, and Jim and Angela Criscimagna. Sigman was one of the first to really drive these skills home, and as a thank-you, much of the tai chi community flamed him for it, because they hadn't been taught these skills (particularly the "softer" tai chi practitioners) so they couldn't imagine that their teachers hadn't taught them the Real Thing.
In Chen tai chi, the most important skill is to maintain peng at all times -- an outward expansiveness in your body structure and movement. Peng jin is part of every movement and each of the tai chi "energies."
But peng is dependent on the ground path, so those are two of the first things that I teach, both in-person, on DVD and online.
One of the Internal Strength exercises that I teach is to maintain the ground path and peng jin while walking. When I first began studying these skills, and someone told me I needed to maintain it while walking forward, I didn't see how it was possible.
There is an exercise on the Internal Strength DVD (and on my membership site) that helps you begin to do this. Here's how it's done:
1. A partner pushes slightly on your chest. You ground the push.
2. You begin walking forward as your partner walks backward, maintaining the pushing pressure on your chest.
If you lose the ground, your partner will feel it "break."
Here are a couple of tips. Relax. Sink your weight (also known as "energy"). Keep your hips tucked as you move. That's very important, because we have the tendency to stick our butts out when we walk.
Remain level. Don't bounce up and down as you walk. Connect with the ground before you begin walking. For example, you stand with your right leg forward and your partner pushes you slightly. You ground it through the left foot, sink and push forward with the left leg, but switch the ground path to the right leg as you go forward.
This isn't easy at first, so keep trying. Eventually you'll understand. You'll feel the pressure of the slight push be maintained throughout your stepping. You won't feel your partner's pressure lessening or disengaging.
Just like all the skills you need for the internal arts, it isn't magical -- it isn't mystical -- it's physical.