It is a group of 4 muscles at the front of the body. They act both on the skeleton (relationship between the pelvis and the rib cage) and on the abdominal viscera (in particular in “forced” exhalation).
Arranged in layers, they are, from the deepest to the most superficial: the transverse abdominal, the internal oblique, the external oblique and the rectus abdominis (that of the chocolate tablet). We have a copy of each of these muscles on the right and on the left. The two sides are linked together by an entanglement of tissues (aponeurosis, sometimes called fascias), which also surround them over the entire width, allowing the layers to slide one over the other.
The system is complex and must be all the more balanced (in tonicity, ability to release and coordination) that the abdominal muscles are postural muscles that act in synergy with the muscles of the back to keep us erect in a vertical position. Too tonic or shortened, they will cause a compression of the abdomen, a flexion of the column and thus also an additional pressure on the perineum. Too weak or chronically stretched, the pelvis will go towards retroversion, taking the column in extension, especially in the lumbar region (L5 / S1, I bet it speaks to many of you, either by theoretical knowledge or by (painful) experience !).
In yoga, they are therefore often recruited in asanas, so it is important to work them intelligently to be able to use them wisely on and off the mat. This is what we teach in the No- Risk Abs® method.