18/01/2023
The transverse abdominis (TVA) is the deepest of the abdominal muscles and it acts as a corset around your mid section between the ribs and the pelvis to help stabilise and protect your spine (and pelvis). Contraction of the TVA, which you can feel if you pull your naval to your spine, is key to safely lifting heavy weights whether its loading your luggage into your car, picking up your 6 year old kid or working out at the gym. When we pick up something heavy a few things happen simultaneously to create intra-abdominal pressure, which takes as much as 40% of vertical pressure off of the intervertebral discs in your spine.
-The TVA contracts pulling naval to spine, which compresses the ribs upwards
-We take and hold a deep breath, which both fills the lungs, exerting pressure outwards 3-dimensionally, and also lifts the diaphragm upwards.
-Because the belly can’t extend forwards when we breathe in whilst the TVA is engaged, internal pressure is exerted outwards towards the back and sides of the rib cage. This forces the whole rib cage to lift up and away from the pelvis, creating a lot of space for the spine.
I like to think of intra-abdominal pressure like a bottle of water - a bottle of still water can be squashed fairly easily in your hands but if you shake up a bottle of sparkling water, the pressure that builds up inside the bottle makes the bottle itself feel like a rigid structure. The same way you could likely stand on a shaken up carbonated water bottle without it breaking its form, the spine and the internal organs are protected by the TVA and intra-abdominal pressure against any weight that you lift or carry. Isn’t the body amazing!
Next post we’ll look at how a C-section child birth can disrupt the core stability and what symptoms you may experience thereafter.