Giving birth has given me a condition called diastasis recti, which is the separation of the abdominal muscles or the rupture of the linea alba. This condition has made getting back into shape harder; I’ll get into details about that in another post though. Knowing that I couldn’t just do normal crunches and other exercises to flatten the belly, I started researching what I could do and I found a book, Exercise After Pregnancy: How to Look and Fell Your Best, in which the author talks about the abdomen muscles and give exercises that someone can do with my condition. I didn’t know you could rupture the linea alba and turns out, after reading the book, there’s a lot I didn’t know about the abdomen.
The abdominal wall is made of four main muscle groups that each have a right and left side. Those muscles are connected in the center by the linea alba.
The first muscle, and the most recognized, is the Rectus Abdominis – known as a “six pack”. This muscle runs vertically from the lower ribs to the pubic bone. It is responsible for the spine flexion, as in bringing your rib cage closer to your pelvic bones when you do crunches.
Then there’s the External and Internal Obliques. Those run in contrasting diagonals across the front side of the body. They flex the spine to the side and help rotate the spine around its central axis. They wrap around the back and insert themselves into the connective tissue of the lower back, which is why they have a role in the alignment and in the stabilization of the lumbar vertebrae. Developing the obliques helps flatten the abdominal wall and redefines the waistline.
The third muscle is the Transverse Abdominis, the deepest layer of the abdominal wall. It has fibers running horizontally across the abdomen and is referred to as the “waist cincher” muscle. It supports the internal organs and stabilizes the pelvis and the lower spine. This muscle is special because, unlike the Obliques and the Rectus, you need to consciously contract the muscle while doing a crunch.
The last muscle is the smallest one and can actually be absent in some individuals. It is the Pyramidalis. This triangular muscle has its apex at the belly button and fans out to connect itself to the pubic bone. When contracted, it lifts and stabilizes the front of the pelvis. It also needs to be consciously contracted. You can actually feel this muscle contracting when you sneeze.
The muscles work in four different groups;
- The prime movers contract concentrically to produce movement. They’re also called agonists.
- The antagonists simultaneously lengthen themselves to allow movement at a joint.
- The secondary movers obviously assist the prime movers.
- The stabilizers are the ones that help maintain body positioning.
The abdominals need to work as both the prime movers, to be able to flex the spine in every way, and as stabilizers, to stabilize the pelvis and the spine. If the stabilize portion of the abdominals isn’t worked, it can cause lower back pain and wear-and-tear injuries in the spine.