In Aikido, all movement comes from the center. In more generic terms, the movement in Aikido can be thought of as moving your hips (lower body) from one place to another. When we think of "movement", we naturally think of how are feet transport us in space from one place to the next. This is not entirely incorrect from a biomechanics perspective, but it is inaccurate from an Aikido or martial arts perspective. As Aikidoists, we should think in terms of our hips and lower body and not just our feet. If we just think feet or footwork then we run the risk of not properly aligning our center (hips) with our feet and thus find ourselves off balance. One's center, hara (Japanese), or dan tien (Chinese) can be found just above where our hip bones crest. We should think of moving this area from one place to the next and not moving just our feet. In order to be "centered" our shoulders need to be back, our hips need to be aligned with our feet and our minds need to be calm. From this place we can meet any challenge in a balanced way from our centers.