Master Yuantong Liu gave a course in which he taught and practiced the Qi Core Improvement Method. This method is based on several exercises of zhineng qigong. If your back aches or your neck hurts it is a marvelous method. Performed in the correct way for several weeks it improves the flexibility of body and reduces the pain in neck and back.
In this video master Yuantong Liu repeats section 1 of this method.