At the end of a hectic day do you have a twinge in your back, knot in your stomach, or pounding in your head? The Chinese believe that aches and pains are the result of a blockage in vital energy, or qi (pronounced "chee"). That's why they developed qigong ("energy work"), a series of simple postures and fluid exercises that work to open up muscles, joints, and tendons so that energy can flow unimpeded throughout the body.