Natalie Portman Ballet Workout: Butt-Buster A tight, toned ballerina butt not only helps you look amazing in your jeans, but it can also help prevent injury. How to do it: Start on all fours, making sure that you have plenty of cushion beneath your knees. Bring one knee into your chest and then extend the leg straight back into arabesque, keeping the knee very straight. Pull in through your stomach and lift your leg high toward the ceiling. Repeat 30 times, and then change legs.