Qi Gong under various names has a long history in China. The written records referring to qi and its effects are as old as 18th century B.C. Numerous books have been written about Qi Gong during the subsequent history of China. The development of Chinese Qi Gong can be divided into three periods:

• In ancient China, people came to believe that through certain body movements and mental concentration combined with various breathing techniques, they could balance and enhance physical, metabolic and mental functions. These movements were worked out over time by exploring the natural range of motion through the joints, as well as drawing on motions in imitation of various animals. This research was passed down and refined according to teacher-disciple relationships of lineage or apprenticeship. This accumulated body of traditional knowledge is known as Chinese traditional Qi Gong.
• In later centuries, these practices became more standardized, very often associated with religious practitioners. For example, incense burning was originally used to measure time and also to repel insects during Qi Gong practice, and eventually became an important part of the meditative process itself. Over time, new forms of Qi Gong were created and passed down through various schools; Taoist, Buddhist, Confucian, Neo-Confucian, Chinese medicine, and the traditional Chinese martial arts.
• In the 1950s, researchers began studying Qi Gong using the scientific method, with peer-reviewed and controlled studies of various techniques to provide a scientific evaluation of claims for the efficacy of Qi Gong. Scientific study of this topic is still active, with particular emphasis in eastern countries, although research into the medical benefits is also active in western countries.

Now various medical universities issue Bachelor’s and Master’s degrees in Qi Gong, or include Qi Gong in their curricula. (content from http://en.wikipedia.org)