In basic defensive techniques, the withdrawing hand first moves forward as far as possible, and the defending hand moves back as far as possible. This makes the performer compact, closed, and "small" when swinging.
Before completing the technique, the arms are quickly pulled in opposite directions, stopping the withdrawing hand at the back of the hip and accelerating the defending hand forward to the end point of the technique with powerful tension. This makes the performer "big." This contrast—small vs. large—allows for maximum power to be achieved through the long path. The resulting interaction between the withdrawing arm and the performer further increases the force that hits the target.
