A method of fatiguing a target muscle group of a user using an exercise device includes grasping in each hand one of a pair of outer handles of an exercise device, positioning the user's feet to be substantially aligned with the user's shoulders while maintaining the user's torso in a substantially upright orientation, positioning each hand in an initial position relative to the user's torso, cyclically pulling the outer handles away from one another in a cyclic motion to apply a cyclic pulling force to the tethers to cause the central disk to alternately rotate in opposing directions of rotation, and moving one or both hands to a secondary position relative to the user's torso and repeating the application of the cyclic force to fatigue the initial target muscle group or to fatigue a secondary target muscle group.