Dear Physiodawn,
My understanding is that the transversus, because of its anatomy, can help to stabilize the SIJ joint, and as well, help to increase interabdominal pressure. This in turn, helps to stabilize the spine.
Have used General Electrics real time scanning ultrasound unit which shows these muscles in action. An interesting look at the anatomy. Richards et al have written books on the subject.
If you want to contact Lisa Quach at General Electric she can probably tell you about the research and the ultrasound equipment. her e-mail address is [email protected]
Sincerely
Lloyd