An exercise system, in a first mode of operation, provides for strengthening of legs of a user and enhancing the user's ability to develop and maintain balance and, in a second mode of operation, for providing various forms of core, arm, and upper body training. The system includes two resilient hemispheres each having a projecting dome and, on an opposite side, a rigid substantially flat weighted base in relationship about each hemisphere and a circumferential ring is proportioned to engage a periphery of the base of each hemisphere. An outer area of the periphery of each base includes elements with connecting rings secured to the engagement elements. Resistance training bands of selectable resistance are securable to one or plural connecting rings. A push-up handle of each hemisphere is press-fittably securable into an axial recess within the weighted base and selectably connects to different weights within the recess.