As has been outlined in the introduction, the tradition of standing to develop or modify the internal energy is a tradition that seems to be largely confined to the Chinese martial and medical practices. There are whole systems, such as the Zhan Zhuang system of Qigong or the Cotton Palm Qigong that have a number of postures which will aid treatment of certain conditions. Put simply you need to learn how to relax and stand still.
Zhan Zhuang sounds very simple but in fact it is quite difficult to achieve. Most standing post exercises will either hold one posture for 20 to 30 minutes or go through a sequence, holding each one for a lesser time.
Standing is the basic practice of Tai Chi. If you do not learn how to stand, you do not learn how to sink the Qi, if you can't sink the Qi, you can't mobilize the Qi, if you can't mobilize the Qi, then you cannot create power or FaJing.
The standing that we teach is the basic building block to sinking the Qi to the dantian. Outside of martial arts, standing practice can help improve your life. The relaxation can help lower the blood pressure, it keeps the mind calm, it loosens the joints, you stabilise and work the legs a lot, so it keeps the muscles working and the heart healthy. The breathing trains our lungs and oxygenates the blood. All of this comes from the bitter work (hard work) and creation of power in the body.
In our school, we teach standing post from the Zuo Lai Feng system, Yang tradition as well as from the San Feng lineage. All of these have a number of basic features BUT we would not recommend practice without the guidance of a teacher.