I've been doing a program called "The New Lifting Rules for Women" over the last few months and have seen amazing results. I used to have a pretty decent figure around SRS time a long time ago, but over the years put on heaps of weight and became quite blobby. This is all coming off now and I'm regaining the shape (actually a better shape) that I had before. This program involves lifting weights (obviously) and a lot of core work - lunges, squats, planking, push ups, body matrix work, Swiss ball crunches etc etc. This combined with better eating habits - no junk food, watching calories, no processed food and lots of whole foods and protein, is working wonders!
I certainly haven't put on any noticeable muscle, but I didn't expect to post op. Just lots of toning. Not sure how the lifting part would work pre op, but the core would work.