There are two centres, one lies in the middle of the pelvic, one exists at wvere the ribcage ends. These two centres line to each other, there is flexibity and it stretches a lot, but never dislocate from each other. However, we do separate these two, one of the most obvious instance is the cucarachas.
The centre is where you generate your energy and where you deliver your energy to the other body parts. If we hold the correct posture, i.e. straighten the spine but not over stretch, keep the frame firm but not stiff, relax the muscles but not collapsing, then energy can transfer to the whole body through the spine and pelvic to reach where we want the energy be.
Body actions should be kept to minimum if we want to feel the flow. But of course, we want to express ourselves and our arms are pretty expressive- when you do things right. However, most dancers overuse or misuse the arm, and head, actions to try to look cool. The way they use the body actions has unfortunately disturbed the balance. When they pay too much attention on the body action they tend to lose control on their centres. Then energy can't be built up, neither can it be deliver to where it should have gone.
Body actions, as said for so many times, should give expression, help your balance, and intensify your beauty. In order to achieve this, the most urgent thing to do is to keep your spine and focus on the centres. A quite explicit evidence of doing it correctly has been your head weight. If you are right, your head is not falling over or falling back, it sits right on top of your body and feels light. If you can shake your body while keeping the head high and light, probably you are okay.
I found the exercises that Hans devised to feel the power of the centres very helpful. Try them and happy dancing.
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