Some people come in to Qigong wanting to learn the most exotic movements and ask what master I studied with. But Qigong is about practice. The more you practice the more you get in touch with your own body, the more meditative you become, the more you start feeling things in your own body. The six healing sounds at first seem little more than sounds, but the more you do them the more they begin to trace back to a memories stored in your body. You can't really talk about this, you have to experience it.
Chinese medicine says that if the energy in the body stops moving, then there is disease.
Qigong keeps the energy moving constantly, and therefore it's preventative medicine.