This tush-targeted workout takes the science of how to tone the three muscles in the glutes to the maximus. “Do all nine exercises for a 360-degree shape-up or pick a few based on your particular trouble spot,” says Kate Albarelli, the creator of the signature Figure 4 class at Pure Yoga in New York City, who designed these proven butt blasters. (That’s Albarelli demonstrating the moves.) To shape more curves, try the Lift It! trio. Tighten your rear with the Shrink It! moves. Got saddlebags? Focus on the Trim It! section. Do two sets of each move you choose three times a week on nonconsecutive days.