An exercise device, for use in strengthening, training, and rehabilitating the body, using at least two harnesses and at least one elastic element. The harnesses are attached to the body and have mating clips attached to them to establish anchor points. The elastic element has a pair of clip receptacle for attaching to the mating elements and has an elastic cord extending therebetween. When the clip receptacles are secured to the mating clips at a pair of anchor points, body movements relative to the anchor points are resisted by the elastic elements.