‘Use Your Core’
Your CORE musculature is the primary source of all movement in the body, plain and simple your core is involved in everything you do physically and should be trained for optimal efficiency, this includes breathing!
Four groups of muscles makeup your inner core;
The diaphragm – your primary breathing muscle attached to the lower ribs and spine
The lumbar multifidus – deep in the low back and attached to every vertebral segment
The pelvic floor – attached to the bony ring of the pelvis from the tailbone to the pubic bone and side. to side.
The transverse abdominis often called the “Lower Abs” – the deepest layer of the abdominal muscles.
A multidimensional approach is needed to facilitate training and responsiveness of these muscle groups.
http://activebodypilates.com/pdf/core.pdf