There are many different body types, but we can do some generalizations. Here we look at what part or parts of the body that are developed or not developed, weak or strong. Tai Chi and IMA practitioners speak about having a strong root and moving from the center. Usually when they speak about combat, they don’t really separate “root” from “center”. But in fact, from both an attacker’s or a defender’s perspective, a strong root and a strong center are separate things. They need separate practice to develop and it needs different strategies to handle a strong root, a strong center, or someone who has both.
This is how we usually divide the body into three parts:
The center is the place from where all of the movements starts. Everything else and all movements are organized around the center. But the center is not only the middle of the body. It is also what connects the top and bottom.
“The Center” is not the same as Dantian. Dantian is the center of the center. If we speak about the middle point of the body as it is used in martial arts, it’s in my own opinion better to speak about concepts as Hara. It’s from the dantian movement should be arranged around, but we also use the area around the dantian to stabilize movement and to connect the legs with the trunk. Here we use the “gua” for the base of the center. Gua resemble more the inside of the hips than the outside. Some people Use this area to initiate movement, some people use the lover dantian, and some people use the upper part of the center, or the the middle dantian, to initiate movement.
If there’s a pressure on a connected arm, or an arm drag against it, how good and strong your root and center are, the body structure will be affected differently. A strong center with a strong base, will keep the whole body in place. A weak center but strong root will divide the body. A strong center but weak root will keep the body together, but the balance will be lost.