While spin kicking, the spinning should be done with the mass as close to the pivot point as possible for maximizing speed and control. This means you must chamber the kicking leg as close to the body as possible. Keep the arms in close. This will increase the speed of the spin and help prevent an off balance spin. Another point to keep in mind while spinning is that the shortest distance between two points is a straight line. While spinning the leg around in the spin side kick, the path the foot travels from the floor to the target should be essentially a straight line. To see this, perform a slow spin side kick and pay attention to the path of the kicking foot.
Spinning may be added to both hand and foot techniques. Spinning techniques are used in most taekwondo patterns and are used extensively in sparring. They add power, speed, and misdirection to techniques, and are used to reach unguarded targets. Spins also permit the user to close or increase the range quickly and deceptively. Spinning adds more power to a technique due to addition of the angular momentum generated by the rotation. Power is affected by how far from the center of rotation (called the axis) the target is located, power is reduced when the target is close to the axis. Spinning techniques are difficult to defend against because of their power, momentum, and unpredictable angles of delivery. Spinning may be used with practically any technique, from practically any stance.
Spinning is dangerous to opponents in that it is difficult to control or stop the spin at the point of focus, or stop the spin when the opponent moves into the spin. Spinning is also dangerous to the user. For example, if you attack with a spinning back fist strike and the opponent suddenly closes the range, your elbow may contact the target first and be hyper extended. For these reasons, it is imperative that the head starts the spin so the target is acquired in enough time to control the technique, or abort the technique if necessary.