HomeReceive the earth's strength," is the way Cheng Man-Ching referred to the powers which have their basis in peng (the ground-vector strength) through a constantly connected body.
Learning to constantly propagate peng to all parts of the body gives great strength and increases the qi. A primitive porter relaxedly carrying a load on his head is employing peng linearly from head to foot. In the internal arts, we train to propagate that available force through the whole body, limbs and exterior surfaces included. By keeping the body connected as a whole, like an amoeba, we can induce all body motions with that ground strength.
With the use of peng and whole-body motion, the force will come through the legs, be directed by the waist, and usually be expressed through our arms and hands. Oddly, as our use of this power increases, so will the manifestation of qi phenomena.
To begin peng training, let someone push against your forearm while you keep your shoulder mildly hyper-extended and your lower back relaxed. You have to feel and build a curved path from where they are pushing against your arm, through your back, and down the rear leg. Let them compress you, don't extend outward... try to relax around this ground-path as much as possible. The knees and waist should be able to wiggle easily while your partner is still feeling the ground-path.
Try retreating downward while maintaining the ground path (peng). Without using any shoulder or arm tension, straighten directly toward your partner... relaxedly straightening into their push.
Notice that the slight hyper-extension of the shoulder not only allows for the easiest propagation of the ground path, but also connects (by extension) the arm to the back.
With practice, you can hold this position and will the ground-path to appear and disappear; very slight body adjustments will probably have to be made at first. Great progress can be made after this is understood.
Body position and angles are important in the propagation of the peng-strength, while using very little muscular effort. This is why it is sometimes said that "internal strength" is the study of angles, on the physical side.
