A fitness ball has first and second hemispheres, which are connectable to form a complete sphere. The first hemisphere supports a motor having a pair of rotatable eccentric masses at opposite ends of a common drive shaft. The second hemisphere supports a rechargeable battery pack, electronic circuitry and indicators LEDs. The electronic circuit controls the charging of the battery pack and also selectively provides electrical power from the battery pack to the motor to control the rotational speed of the motor to rotate the eccentric masses. The rotating eccentric masses cause vibrations that are communicated from the motor to the two hemispheres. The vibration frequency is controlled by the rotational speed of the motor. The hemispheres have outer covers having a configuration that is easy to grip such that the vibrations are communicated to a users hands. The ball is substantially balanced about an equatorial plane.
