We love Pilates. We love HIIT (that's high-intensity interval training). When Blogilates founder Cassey Ho put the two workouts together you get an ab-centric PIIT workout. And it's awesome. You do each of the seven moves for 45 seconds, followed by a 15-second break. Do the workout once, or repeat for a total of four times to make a killer 28-minute sweat session.