Though resistance exercises have no ability to spot-reduce, they can definitely spot-enhance, and exercises like weighted side bends or heavy Russian twists have the potential to add size and bulk where it’s not wanted. To carve a long, lean torso with all the right cuts, aim for moves that use a large range of motion such as this one, where the external obliques are the star of the show. Using the BOSU allows you to stretch the obliques by extending over the dome and works them both concentrically and eccentrically throughout the range of motion.