I gained about 20 lbs. during my pregnancy, and gave birth to my beautiful blue eyed 7 lb. 9 oz girl. It's hard to admit because I know a lot of people frown upon and judge women who get back to pre baby weight quickly, but I did manage to return to pre-baby weight the week I gave birth. It wasn't something I purposely made the goal of doing (as I vowed to be patient with myself), but once I lost the large amount of water weight I had retained after giving birth (and adding breast-feeding on top of that), my metabolism revved up to the point I soon dropped below pre baby weight. Unfortunately, at that point I had lost quite a bit of muscle and was about 5-10 lbs. below pre-baby weight.
I had a grade 2 tear so of course I was given the standard 6 weeks of recovery timeline, so most of my "bounce back" I credit to nursing and giving my body time to recover. The recommended recovery time was frustrating at the time, but necessary to ensure there was no further setback. With my body healing day by day I began lifting light arm weights while still avoiding any exertion with the lower half of my body. I did wait the entire 6 weeks before starting any resistance training with the lower half of my body. I'm thankful I did wait because my body needed the time to heal.
While I could hardly do any type of workout during the recovery period, I did begin pelvic floor exercises immediately. This played a huge role in my postpartum recovery as well.