How Hard is It to Pop a Suture After Tummy Tuck?

Moderately easy, but it depends upon many factors to answer this concern adequately. Seek opinion from the surgeon who preformed the tummy tuck.

From MIAMI DR. B

Although it is conceivable to disrupt a stich following an abdominoplasty, most repairs are layered with imbricated closures, affording a strong repair of the diastasis.  Having said that, we recommend our patients from refraining from any heavy lifting for a period of no less than 8 weeks in order to ensure that adequate time is given for healing. Post-procedural protocols will vary from surgeon to surgeon.

It is not hard to tear a muscle repair stitch. Any activity that suddenly pulls on the tummy muscles can do it; Vomiting, lifting, sit ups etc- can all do it. But the likelihood of breaking and then of bleeding and or of muscle separation would depend on the strength and thickness of the muscle lining (fascia), the thickness and type of stitch used and how it was placed and the amount of time that passed from surgery which would have allowed scar tissue to form and spread tension forces across a wider surface than just the suture line. You should not be lifting for a few weeks after a tummy tuck.