Center City is finally seeing an upsurge of studio openings, meaning Pilates addicts no longer have to hike to faraway lands (read: Northern Liberties) or settle for free-with-gym-membership classes. And its recently opened Urbanfront that has us hooked. The inviting space is divided in two, with a glassed-in sunny studio area where experienced, tight-bodied and patient teachers who arent afraid to get physical guide small, classical mat classes and offer innovative sessions that incorporate cardio or the latest in gadgets. (Wunda Chair, anyone?) In the Reformer machine-filled half, owner Karen Pecarsky gives meticulous consideration to her private, duet or small-class lessons, focusing on proper move mechanics and feeling the burn. Class times are varied, private bookings are flexible, and prices are reasonable.