Just think of it as a "theraband" or exercise band for the diaphragm. The fine Physical Therapists from the Postural Restoration Institute taught me the technique and it continues to be a favorite. It is worth the effort because it simply fixes many musculoskeletal issues with postural adjustment while it calms our nerves through the PNS (parasympathetic nervous system/activation of the vagus nerve). Plus it strengthens the diaphragm, our main respiratory muscle!
The 90/90 position using a chair for the heels and the back flat on the floor is a great place to start. Other positions, where the pelvis is in a posterior pelvic tilt is effective because new neural pathways can be formed recognizing that the front lower ribs are most effective for the diaphragm when they are not flared, when they are down, back, and in. It is amazing how even centimeters of adjustment makes a difference to the neural connections of the brain and body.
*Join me in the video to try it. Get a 12" balloon first.
*Please read this article- "The Value of Blowing Up A Balloon":