The creator of Pop Physique attended classes during her pregnancy and she still thinks the workout's thigh exercises are more difficult than having a baby. Founded by former dancer Jennifer Williams, the rigorous fitness classes combine ballet, Pilates and several rounds of pelvic tucks. The classes began at Pop Physique's flagship Silver Lake locale but, with Williams' tireless energy, have expanded to locales in Studio City, Marina del Rey, the Westside and Costa Mesa. The expanding, distinctly feminine Pop Physique fitness regime includes light weight lifting, squeezing a ball between thighs and standing on tiptoe as if you're wearing high heels. Several of the instructors have a dance background, which may explain why there's a practice of small controlled movements that take center stage each session, along with a careful grace. After-class sore limbs are standard. But devoted Pop Physique–goers report seeing their bums rise into pleasing round shapes and thighs and tummies become leaner. Of course, it's not without effort. 3501 W. Sunset Blvd., Silver Lake. (323) 665-7777, popphysique.com.