Transverse abdominus

Hi, Camille. Recently I heard about transverse abdominus muscle. Does this muscle help to control diaphragm stay flat ?

Yes, the TVA is one of the muscles the diaphragm is attached to! When we activate our abdominal muscles, they help to keep the diaphragm flat and low. And the longer our diaphragm stays low, the longer we can sustain on one breath. Here's a study you may find interesting!