In Practical Method, “out with the hand, no elbow; in with the elbow, no hand.” It tells the relationship of hand and elbow. Recently I used a ball to help beginners to understand this principle. I found it’s quite helpful to me also.
The Ball: about 8 in diameter, about 80% inflated. Fig. 1.
When we withdraw elbow, use the upper arm to hold the ball. Withdraw elbow along the forearm. The power is in elbow. The hand is passive, no power. Fig. 2. The position of the forearm is in front of the body in 45 degree angle.
In Yilu, whenever we need to withdraw elbow, hand, elbow and forearm most time won’t be in ideal 45 degree angle position as in Fig. 2. In this case, to withdraw elbow requires highly coordination between elbow and shoulder. No matter where the forearm is, the energy alignment in elbow withdrawal is on the longitude line of the forearm. We cannot allow the forearm do the horizontal move. To withdraw the elbow, we need to adjust the position of the forearm, also make the shoulder to press down. With a series of adjustment made by elbow in and shoulder down, as well as the hand position being fixed, the forearm slowly makes its way to 45 degree angle.
With the ball, you can get the feedback from the ball wether you are doing correctly or not. See Fig. 3 to 7.
These are just my quick notes. I also found if the shoulder is tight, it’s hard to withdraw the elbow to the right position.