Getting a little technical, your diaphragm is attached to your lower ribcage, thoracic wall, and lumbar vertebrae. When breathing is executed properly the diaphragm expands into the abdominal cavity on the inhale. This movement causes a pressure change which pulls air into the lungs. As a result of the diaphragmatic movement, intra-abdominal pressure increases and lumbar spine stiffness, better known as stability, also increases. The diaphragm acts in coordination with the abdominal muscles, spinal muscles, and pelvic floor to create lumbar stability in all directions. This is what some in the Pilates community refers to as “360 degree of stiffness.” The contraction of the diaphragm creates core stability from the inside-out.
Focusing on inhale and exhale during movement helps your body move in a more efficient way. As your mind focuses on the breathing, your awareness naturally spreads to the parts of the body in motion and you feel the connection taking place. You’ll find this meeting of mind and body becomes instinctive, to the point that the next time you’re practicing Pilates, or lifting your baby, or running, walking, even laughing, your breath will fall in line and you’ll feel more coordinated and in command of your activity.
Joseph was not an educated man in the traditional sense but intuitively knew and by careful observation, learned the importance of breath. "To properly deflate the lungs is an art in itself and this final step in correct breathing is least understood. ...It is seldom, if ever, taught unless the individual is privately coached by one who understands what it really is all about." - Joseph Pilates from Your Health
Are you creating the connection between your breathe and your practice of Pilates? If not, work with you instructor on the most basic of the Pilates Principles.
To learn more on the origin of Pilates visit: https://www.pilates.com/BBAPP/V/pilates/origins-of-pilates.html