While we commonly associate the diaphragm with breathing, this often-forgotten muscle has an equally important role in helping to create body-wide dynamic stabilization to optimally support the wide range of movements us humans are capable of achieving.
The diaphragm is a muscle located underneath our rib cage, spanning from the bottom of the sternum all the way to the spine. As we take a breath in, the diaphragm descends toward the pelvic floor. This descension creates negative pressure in our lungs allowing air to come in—similar to pulling liquid into a syringe. As the pressure decreases in our lungs it simultaneously increases in the abdominal cavity, causing the abdominal region to expand as we inhale.
This increase in abdominal pressure creates what is called an eccentric load on our abdominal wall, pelvic floor, and segmental spinal stabilizers (an eccentric load means that the muscles are activating, but in a lengthened position—think of a bicep curl, as you bring the weight up your bicep is shortening as it contracts, however as you slowly lower the weight back down, your bicep is still active, but it is active in an eccentric, or lengthened position). If maintained, this activation helps create synergy, coordination, and control of these “core muscles” to stabilize our spines and abdominal region and optimize movement patterns. Ideally, this activation should naturally and subconsciously precede any planned movement.
It is through this reactive eccentric activation of these muscles that we achieve proper stabilization of the abdomen and spine. Utilizing the diaphragm to create, maintain, and modulate pressure in the abdominal cavity creates synergy between the diaphragm, pelvic floor, abdominal wall, and segmental spinal stabilizers. This synergy, coordination and control allows this system to work as a unit to hold the spine up against gravity, allow for segmental spinal movement, provide the stability for movements of the limbs, and optimally transfer kinetic forces through the body. Diaphragmatic stabilization aligns the body to move with optimal joint positioning—termed joint centration—providing the maximum area of contact between joints as they move through their natural planes of motion. These factors are critical in supporting both function and performance of the wide variety of movements humans are capable of (walking, jumping, running, rolling, throwing, swinging, etc.).
While this may sound a bit complicated at first, the activation of this system is engrained into our nervous system at birth and provides the essential foundation to develop the ability to roll, crawl, and eventually walk over the first year of life. This system remains with us throughout adult hood and will naturally and subconsciously activate preceding any planned movement. Together this provides controlled, coordinated movement throughout the body.