I've heard that lifting heavy will help your pelvic floor, especially squats. I haven't had any children but I've been having some pelvic floor issues (sprinting is a horror to be done only on an extremely hot day so that it just looks like I'm very sweaty.) It's my hope the squats and other core-building lifts will help. Since the problem comes and goes based on god knows what, I have yet to know if it's been successful.
Female, 5'3", 49, Starting weight: 163lbs. Current weight: 135 (more or less).
Starting squat: 45lbs. Heaviest squat: 180 x 2. Heaviest Deadlift: 230 x 2