Ready to re-start your fitness routine after giving birth to your bundle of joy? Kara Douglass Thom, author of "Hot (Sweaty) Mamas," shows us a simple-yet-challenging routine to regain strength in your core, glutes, hips and the all-important pelvic-floor muscles. Perform each exercise -- developed by Shirley Sahrmann -- in sequence, gradually working your way up to 20 repetitions before moving on to the next exercise.