The most effective way to grow and tone your booty is through weightlifting. The glutes are the largest muscle in your body and require very heavy resistance to see results. Hip thrusts isolate the glutes without compressing your spine, making them a top booty workout that almost everyone can perform. Take your glute performance to the next level by developing a Phirm™ booty. Grow, tone and Phirm™ up your booty by performing high resistance hip thrusts and glute training. No more sagging, Phirm™ iiT!™ Up.