Orbital, spiral or sometimes called dual motion machines combine the oscillating (see-saw) and tri-planar (front back) motors creating a figure-8 motion. This is a very gentle motion on the back and joints. These machines are ideal for weight loss, lymphatic drainage, circulation, improved bone density, pain reduction. These two motors may be run separately, giving you the additional benefits of muscle toning, reduction in swelling and muscle building. If you want the most bang for your buck these machines are the way to go.