What is different about Tai Chi movements and other martial arts or exercises?
All movement is initiated from the dantian, and your whole body literally moves together. If your dantian moves an inch, your shoulder will move and inch, your elbow will move an inch, and your hand will move an inch. There are no movements where one part of the body moves in isolation. I would say that a good athlete will move in a similar way some of the time, particularly when applying maximum power in a large movement. Tai Chi has analyzed this mode of movement and applies it all of the time: for the smallest movement as well as for big, and for gentlest movement as well as for the violent ones. This way the body is always ready to produce power, and to change the direction of the power.