Abstract: An exercise device includes a body having rib-like structures and an annular band. Each rib-like structure has an exterior surface defining a longitudinal extent, terminates at a radiating end, and has at least one wing formed substantially parallel to the longitudinal extent and protruding away from the exterior surface to a given distance that increases along a direction towards the radiating end. The rib-like structures overlap at a central point to comprise a central base. The annular band is connected to the radiating end of each rib-like structure such that the rib-like structures and the band together form a cup-shaped enclosure operable to seat therein a bottom portion of an exercise ball. The at least one wing of each rib-like structure is operable to provide an incremental resistance against a rolling movement of the exercise ball along a substantially flat surface when the exercise ball is seated therein.