When holding up the arms, the qi is threaded together continuously.
When the left side is heavy, it then empties, and the right side is already countering.
When the right is heavy, it empties, and the left is already countering.
The qi is like a wheel, and the whole body must mutually coordinate.
If there is any uncoordinated place, the body becomes disordered and weak.
The defect is to be found in the waist and legs.