Breathing - Lungs and Diaphragm

Your lungs are big! They extend from your collar bone to the bottom of your rib cage. At the bottom, they are attached to a muscle that goes across your abdomen called the diaphragm. When the diaphragm is resting, is curves up into the lungs, making the breathing space smaller. When the diaphragm contracts, it pulls downward, and pulls the lungs with it. This is how breathing works – FIRST the diaphragm goes down, and then air gets pulled in. This is how you get most of the air into your lungs. You can also get a small amount in by simply breathing into your chest and expanding your ribcage. But because the ribcage is meant to protect, it doesn’t expand much.

So, to get your lungs full of air, your diaphragm must go down when you inhale. You’ll know if you’re doing this, because your abdomen (and sides and back) will expand. When you exhale, the diaphragm will go back up, and your abdomen will shrink again.
Shoulders should not rise when you inhale.
Think "IN - FAT; OUT - SKINNY"