Notes on Noi Gong

 From Wikipedia:

      Neigong, also spelled Nei Kung, neigung, or noi gong, is any of a set of Chinese breathing, meditation and spiritual practice disciplines associated with Daoism and especially the Chinese martial arts. Neigong practice is normally associated with the so called "soft style", "internal" or nèijiā 內家 Chinese martial arts, as opposed to the category known as waigong 外功 or "external skill" which is historically associated with shaolinquan or the so called "hard style", "external" or wàijiā 外家 Chinese martial arts. Both have many different schools, disciplines and practices and historically there has been mutual influence between the two and distinguishing precisely between them differs from school to school.

    The martial art school of neigong emphasises training the coordination of the individual's body with the breath, known as the harmonisation of the inner and outer energy(內外合一), creating a basis for a particular school's method of utilising power and technique.

     Neigong exercises that are part of the neijia tradition involve cultivating physical stillness and or conscious (deliberate) movement, designed to produce relaxation or releasing of muscular tension combined with special breathing techniques such as the "tortoise" or "reverse" methods. The fundamental purpose of this process is to develop a high level of coordination, concentration and technical skill that is known in the martial arts world as neijin (內勁). The ultimate purpose of this practice is for the individual to become at one with heaven or the Dao (天人合一). As Zhuangzi stated, "Heaven, earth and I are born of one, and I am at one with all that exists (天地與我並生, 萬物與我唯一)".

    This type of practice is said to require concentration and internal reflection which results in a heightened self-awareness that increases over time with continued practice. Neigong practitioners report awareness of the mechanics of their blood circulation, peristalsis, muscular movement, skeletal alignment, balance, etc.

From Jim Roselando:

Wai Gong is the external exercises of the muscles, tendons etc..

Noi Gong is the internal exercises of the breath & qi...

So! Soft qigong is actually noi gong.  

The horse also must fall into the "natural" category if it is to work the noi gong. That means your ankles, hips, shoulders line up vertical/horizontal to allow for natural flow. They call that external 6 harmonies.