Qi Gong (Chi Kung) literally means Energy/life-force Skill. The Gong is the same as the Gong of Gong Fu (Gung Fu). This implies excellence.
Yang Shen, or Nourishing Life, is a sub-study of Qi Gong.
In general, Qi Gong can be divided into yin and yang, or water and fire methods.
In the water methods one would include Taoist Golden Flower cultivation, Shen Gong, Xiantianqi, Pathways of the 8 Immortals, Zen meditation, Bahai/Jewish/Gnosticism, and softer types of pranayama yoga.
In the fire methods one would include the Microcosmic Orbit, Houtianqi, kundalini, bikram, and hatha yoga, kriyama, Yi Jin Jing, Hua Tuo’s Five Animal Frolics, Taoist Short 32, Tantrism/Vajrayana and many more.
The difference between water methods and fire methods is the usage of the light to either project or turn back to receive. This light, also known as the Christ/Krishna light (corresponding to the Heart Chakra), is roughly to be thought of as focus. Whatever one’s thoughts focus upon is where the light goes.
Fire methods focus on the externals to build the internals, and are very good for moving excess of Qi.
Water methods focus on the internals, and the center, and are very good for cultivating (tonifying) the Qi, and calming the mind for observation.
Qi Gong has many lineages, especially if you include yogic practices as I have noted above. It is all one body, after all. The commonalities are the Tree of life with its 7 (or 8) chakras, the 12 main channels and 4 deep channels, and the 3 minds and 3 bodies.
What are the 3 minds?
What are the 3 bodies?
Using Qi Gong, one simply inflates the Qi Body to make a larger bubble surrounding one, and in so doing, protects the physical from internal and external oxidation (rusting) and therefore aging. The body can repair, but its ability is limited by the amount of daily Qi, ying, and overall Jing (essence) available, and the flow of the blood (Xue) and fluids (jin-ye) which carry ying qi (nutrients) to the tissues of the Qi Ji (body machine).
Qi Gong, properly performed, also eliminates the excessive sense of ego as a real object (maya) and its attachments (skandhas); thereby enhancing sense of healthy self, confidence, humility, relaxation, and long term health. Improperly performed, it can remove vital energy and Qi from one location into another, reverse the flow of the channels, and hasten death. Therefore it is vital for individuals to seek out competent teachers and source-texts to improve overall health, well-being, and life-span safely. This practice, called Alchemy, is vital to the achievement of purpose in life.
The following texts are canonical in their arenas: