Understanding how to practice the thirteen dynamics

Use mind to move energy. You must get the energy to sink. It is then able to collect in your bones. Use energy to move your body. You must get the energy to be smooth. Your body can then easily obey your mind.
If you can raise your spirit, then you will be without worry of being slow or weighed down. Thus it is said [in the Thirteen Dynamics Song]: “Your whole body will be nimble and your headtop will be pulled up as if suspended.”
Your mind must perform alternations nimbly, and then you will have the qualities of roundness and liveliness. Thus it is said [in the Thirteen Dynamics Song] that you are to “pay attention to the alternation of empty and full”.
When sticking with an opponent, you must go along with the situation to adjust your intent, which amounts to nothing more than clearly distinguishing empty and full, and then you will automatically have the qualities of being rounded and lively, alternating empty and full with constant efficiency.
When issuing power, you must sink and relax, concentrating it in one direction.
Your posture must be straight and comfortable, bracing in all directions.
Move energy as though through a winding-path pearl, penetrating even the smallest nook, meaning the energy is everywhere in the body.
Wield power like tempered steel, so strong there is nothing tough enough to stand up against it.
The shape is like a falcon capturing a rabbit. The dynamic is like a cat pouncing on a mouse.
In stillness, be like a mountain, and in movement, be like a river.
Store power like drawing a bow. Issue power like loosing an arrow.
Within curving, seek to be straightening. Store and then issue.
Power comes from your spine. Step according to your body’s changes.
To gather is to release and to release is to gather. Disconnect but stay connected.
In the back and forth of your arms, there must be folding. In the advance and retreat of your feet, there must be variation.
Extreme softness begets extreme hardness. Your ability to be nimble lies in your ability to breathe.
By nurturing energy with integrity, it will not be corrupted. By storing power in crooked parts, it will be in abundant supply.
Your mind makes the command, the energy is its flag, and your waist is its banner.
First strive to open up, then strive to close up, and from there you will be able to attain a refined subtlety.
It is also said:
First in your mind, then in your body. Your abdomen relaxes and then energy collects in your bones. Spirit comfortable, body calm – at every moment be mindful of this.
Always remember: if one part moves, every part moves, and if one part is still, every part is still.
As the movement leads back and forth, energy stays near the back and gathers in the spine. Inwardly bolster spirit and outwardly show ease.
Step like a cat and move energy as if drawing silk.
Throughout your body, your mind should be on your spirit rather than on the energy, for if you are fixated on the energy, your movement will become sluggish. Whenever your mind is on the energy, there will be no power, whereas if you ignore the energy and let it take care of itself, there will be pure strength.
The energy is like a wheel and your waist is like an axle.