When you think about abs, you probably picture those infamous "six-pack" muscles (which, by the way, are not required for a strong core), but there's much more to know.
The quick tour below will help you better understand these dynamic muscles and how they work in conjunction with your pelvic floor.
Your Abdominal Muscles, Explained
As you can see in the abdominal muscles diagram below, the front of your abdominal wall is made up of four layered muscles: the rectus abdominis, the external obliques, the internal obliques, and the transversus abdominis.
All four of these layers work together to assist with:
- Voluntary movements such as bending, rotating, and stabilizing your spine
- Involuntary movements like breathing, sneezing, coughing, and vomiting
- Maintaining intra-abdominal pressure within your core — this pressure prevents your body from collapsing in the middle and protects your abdominal organs and spine
Each of these muscles is surrounded by layers of connective tissue that help to support its function. These connective tissue layers come together to form a sheath around the rectus abdominis muscle before eventually forming the linea alba straight down the midline of the abdomen.
The Rectus Abdominis
Popularly known as the six-pack muscle, the rectus abdominis muscle runs front and center from the bottom of the rib cage, to the pubic bone and helps to bend your trunk and push air out of your lungs during exhalation. It also puts pressure on the front of your abdominal organs to increase intra-abdominal pressure.
The Internal & External Obliques
The internal and external obliques are the abdominal muscles to the sides of the rectus abdominis. These muscles are layered with the internal obliques lying just underneath the external obliques. These muscles work together to help you twist and bend the trunk.
The Transversus Abdominis
The transversus abdominis is the deepest abdominal muscle layer and wraps around your middle acting like a deep back brace. It helps to support your low back area and the abdominal organs.
How Your Abs Work with Your Pelvic Floor
Your abdominal muscles aren't designed to work in isolation; they function in coordination with other key muscle groups, including your pelvic floor muscles (shown in the diagrams above, at the base of the pelvis).
The deepest abdominal muscle layer, your transversus abdominis, co-contracts with your pelvic floor muscles. When contracted together, these muscles are stronger than when contracted individually, improving support to the low back and pelvis, and optimizing pelvic floor muscle function. This co-contraction should happen naturally, but if you have pelvic floor muscle dysfunction, this co-contraction can be less effective.
Your abs and pelvic floor muscles also contract and relax/lengthen along with your diaphragm in order to support breathing and management of intra-abdominal pressure.
Located at the bottom of your rib cage and right under your lungs, your diaphragm is the main muscle that helps you breathe.
When you inhale deeply into your belly, your diaphragm expands downward, creating space above for your lungs to fill with air. This movement creates pressure on your pelvic floor and abdominals, encouraging them to stretch and lengthen with each inhale. As you exhale, your diaphragm moves back to its resting position, and the pelvic floor and abdominals contract to help move air out of your lungs, as shown below.
When weakened or injured, the performance of the abdominal muscles is affected and can contribute to a variety of issues including:
- Leakage (gas, urine, or stool) with coughing, laughing, and sneezing
- Low back pain or pelvic girdle pain
- Diastasis rectus abdominis
- Inefficient breathing mechanics
- Abdominal pain
- Sexual dysfunction, including pain with sex or orgasm dysfunction
The good news is that your muscles can be retrained through physical therapy. By focusing on deep abdominal muscle strengthening and coordination, you can optimize your pelvic health and get everything working together again.