How do we get the diaphragm back online and functioning to its full potential? Yoga is one of the most breath-focused systems of exercise and ways of living and can definitely help whip your diaphragm into top shape!
Here's a simple little visualization exercise you can do to help your brain and diaphragm muscle communicate more efficiently:
You can do this breath in any position (even standing or sitting at your desk!), but many people find it easiest to learn for the first time lying down face up in a comfortable position - knees bent is fine if that feels better to you. Yogis: try savasana, legs up the wall (vipirita karani), supta baddha konasana or even child's pose. Really any restorative pose that's comfortable to you works great. If you're familiar already with a diaphragmatic breath or three part breath - this is a little different. Give it a try!
Visualize the diaphragm as a dome just below the nipple line - like an umbrella or parachute. As you inhale, the diaphragm contracts, moving the dome down toward the base of your pelvis. On the exhale, the diaphragm relaxes, moving back up into it's peak dome position, pushing the air out of your lungs. Inhale, fill air all the way toward the base of your pelvis. Exhale, allow it to move up and out.
This should not cause a huge rise and fall of the belly. Naturally, there will be a little bit of movement, but if there is too much, it is a sign that there is not enough mobility elsewhere to allow your diaphragm to descend fully (maybe the ribcage isn't expanding to the back or sides....maybe the pelvic floor is not relaxing enough). The muscular pelvic floor (the muscles at the base of the pelvis that we've discussed in more detail here) relaxes and descends in phase with the descent of the pelvic floor on inhale (3). This does not mean that you bulge out the pelvic floor on an inhale like you would if you were pushing out a constipated poo. It's a small relaxation movement away from the head on inhale, followed by a natural uplift on the exhale (in phase with the diaphragm's uplift on exhale).
2. Vostatek 2013. Diaphragm Postural Function Analysis Using Magnetic Resonance Imaging. Available free full text online: http://www.plosone.org/article/info%3Adoi%2F10.1371%2Fjournal.pone.0056724
3. Talasz 2011. Phase-locked parallel movement of diaphragm and pelvic floor during breathing and coughing—a dynamic MRI investigation in healthy females. Int Urogynecol J 22:61–68.