Lower Back is first to command

This is interesting. It is from Paul Brennan's site where there are a lot of really interesting translations of tai chi, xingyi etc books.

"The lower back is first to command, the throat second to command, solar plexus third to command. The elixir field is first to obey, palms second to obey, the soles of the feet third to obey."

The full text can be read here

Careful reading is required and there are many gems that can be discovered.