In Tai Chi Chi Kung there are physical and energetic expressions of the energy. These expressions can be used for health and for self defense. There is a bit of difference between the physical and energetic expressions and I will attempt to elaborate here.
Some physical expressions of Tai Chi Chi Kung include Peng, Lu, Ji and Ahn which translates to Ward Off, Roll Back, Press and Push. The reason that these are included as Chi expressions (Jing) is that it is not just the physical action described or any individual movement that makes the expression. Instead it is the direction and intended expression of the energy that is the focus in these 4 basic jings.
Some of the better known energetic expressions of Tai Chi Chi Kung include Fa Jing – Explosive energy, Jian Si Jing – Silk Reeling Energy, Ting – Listening Energy, Rooted Heavy Energy, Sticking Energy, Borrowing Energy and Electrical Energy. The majority of these energies are simply different energetic expressions of the same force. I will use some physical examples here to make the point.
The application of energy in Tai Chi Chi Kung is more profound than I am about to describe and much more can be and is done than I am describing here. I am simply using a very crude and simple physical illustration to help make the point about how the human body can do things differently. If I put my hand on a door that is mostly closed but not completely closed I can jolt the door shut without having to move my hand from the door. That jolt expression is akin to fa jing. If I feel the inside of the door and through the door to the other side and feel the latch of the door and that it is not closed and how much pressure is pushing back through the door and where it is coming from then that is akin to ting jing. If I let my weight drop down through my legs so that my dropping body weight shuts the door then that is akin to rooting heavy energy. Again, please do not take these to literally as there is quite a bit more involved in jing expression than the very physical example I am giving here.