Does Plication During Tummy Tuck Strengthen Abdominal Wall?

The muscles of the abdominal wall need to be in the right position in order to work properly. If the connective tissue anchoring these muscles in position has stretched through pregnancy or weight gain, it may be very difficult or near impossible to get those muscles working. A plication alone does not strengthen the abdominal wall, but it does put everything back into position so that the exercising you do gives you maximum benefit.

The plication itself does not strenghten the abdominal wall but it does reposition the rectus muscles to make exercise more efficient and enhance the potential to strenghthen the abdominal wall through exercise.

Smallernow,
Congratulations on your weight loss!
I would like to address "I have lost 200 pounds, and have had several abdominal surgeries over the years, and 7 hernia surgeries. 3 in 3 years. All this left me with severe diastasis rectus "
Our bodies have been engineered / evolved a safety valve to allow gradual increasing intraabdominal volumes. As your intra abdominal volume increases (pregnancy's growing baby, increasing intraabdominal weight, large ovarian mass etc), the rectus muscles slowly separate and go to the sides ALLOWING a slow expansion without undue compression on the heart and lungs. More over, the rectus muscles are thinned AND there is distancing between the lateral borders of the rectus muscles and the lateral 3 muscle group (ext. oblique, int. oblique and transversus abdominis). ALL this translates into a virtual dilatation, stretching and increase in the intraabdominal volume.
To get a flatter tummy, all this excess, needs to be repaired by literally hemming or reefing it in.
A diastasis repair will NOT "strengthen" the muscles the way 1,000 sit ups a day for years would (I DID have a patient who did it to tighten her tummy...), because exercise will cause muscle hypertrophy and definition. BUT - a well done midline repair WILL completely correct any midline weaknesses and hernias and SHOULD make things much tighter making future midline hernias VERY unlikely.
I hope this was clear.