Qi Gong (氣功) is a method to enhance life through physical and mental work (breath combined with exercises).
氣 Qi = Essence/body inner energy life span
功 Gong = skill/work
The wonders of this art are huge. The Wudang Pai system referes to the 5 animals (Crane, Turtle, Snake, Tiger and Dragon) as Wu Xing Nei Gong (五行氣功). The Wu Xing Qi Gong are five basic health internal exercises from the Daoist tradition. They follow the principles of Tu Na, Liang I and Yang Sheng Fa.
"When one conducts the Qi, the deeper one breathes, the more Qi one stores; the Qi extends downwards, becomes fixed and consolidates. Then it germinates and grows upward and downward. One has to follow its natural course of circulation. If one does, one lives; and if not, one dies."
Yu pie (380B.C)