With your history of physical fitness and weight loss and of having several children it is safe to assume that you are at the maximal best that can be achieved by exercise. If any further improvement is to be had, it would need to come with the help of one of my Plastic surgery colleagues.
The odds are hands down that you have abdominal wall looseness (from the pregnancies). That would place your six pack muscles (rectus abdominis) to the sides and they will NOT come together. No matter how hard you exercise - the separation of the muscles and looseness of the tummy will persist, as you have already seen. You would probably greatly benefit from an ABDOMINOPLASTY (tummy tuck) with or without liposuction.
You may read more about it here http://www.cosmeticsurgeryspecialists.org/bodyprocedures/mommymakeover.html#- and here http://www.cosmeticsurgeryspecialists.org/bodyprocedures/tummytuckabdominoplasty.html#.
Good Luck.
Peter A Aldea, MD, FACS
www.TheBeautyDoctors.com
