Power

Beginners focus upon gaining a basic familiarity with the exercises.

Intermediate students seek to improve their biomechanical efficiency in order to develop 'obvious power' (ming jing). 
This stage of practice is all about coordinated movement: "square on the inside, round on the outside."
The student avoids locking their joints, tensing muscles, leaning, stooping and using force.

Experienced students study hidden power (an jing), making the movements smoother, more flowing and less overt.
Every exercise is infused with neigong.

An expert achieves refined power (hua jing) by doing most of their work internally.