Two inspired ideas join forces: the Swiss exercise ball and the concept of a workout for all the muscles of the body core. Working out while sitting or lying on the inflatable ball--which comes in sizes from 18 to 30 inches--stimulates the sense of equilibrium and promotes synergy between muscle groups. The workouts, which use dumbbells or ankle weights to tone muscles and promote weight loss, also build better coordination, improve posture, and equalize...