Hua To, the most famous doctor of the Eastern Han dynasty, said that “water that runs doesn’t putrefy” and “hinges that move do not rust.” (Actually, he said that hinges that move are not eaten by worms, because in those times hinges were made of wood.) Movement of the body causes the blood and energy to flow, improves the function of the internal organs, and aids in digestion and elimination of waste products. However, one must perform a suitable amount and type of movement: neither very demanding, in order to avoid injuries (“you must listen to your body”), nor very easy. Movement will then be effective in allowing us to transcend the limitations set by pain and by bad habits. Ultimately we prevail over ourselves. Each person should act as his own medical instructor and guide, as there is no one who knows his body better than himself.
Great emphasis is placed on stretching in such diverse systems of health and personal development as Hatha Yoga and some forms of Qigong. Stretching activates the flow of energy and blood through the body causing genuine healing. The natural tendency of the body is to shrink, stagnate, and shut down (especially when pain exists, for example in rheumatoid arthritis). We must fight against this tendency. Stretching muscles and tendons and mobilizing and opening joints allows a greater flow of blood and Qi. Stretching also flushes the meridians resulting in improved range of motion, diminished pain, delayed overall degeneration, and in some cases the healing and regeneration of tissue.
In a river whose current is powerful, the water drags away waste (wood, bottles, plastic, branches, etc.). But in a slow-moving river the waste is accumulated along the banks; in the same way, a deficient flow of energy and blood through meridians and arteries allows toxic products to accumulate in the walls of these conduits, damaging them. In contrast, a powerful flow of energy and blood nourishes all the parts of the body, oxygenates, revitalizes and prevents accumulation of toxic products, dragging them to purification centers or places of elimination. This movement of blood and Qi is really the final goal of Qigong. The ability of Qigong to cure physical diseases, mental imbalances and spiritual ignorance is obtained through movement of the body, breathing, and control of the mind.
The self-massage of specific points on the body mobilizes blood and energy. It can be used either to strengthen or calm the Qi.