Those of us interested in fitness love to talk abdominals. We throw around terms like great abs, six pack abs, flat abs and ripped abs all the time. But we are really talking about a specific set of muscles that have distinct functions yet work as a team.
Take this short tour of the abdominal muscles. Understanding how the abs are put together and how they help us move will help you get the most of the abdominal exercises that are part you workouts.
Rectus abdominis is the most famous abdominal muscle. It is the one responsible for the look of "ripped abs." A long muscle that runs down the front of the trunk, rectus abdominis starts at ribs 5 - 7 (count from top down) and the base of the sternum (breast bone), and runs all the way down to the top of the pubic bone. The fibers of the rectus abdominis are parallel to each other and contained in a sheath. They are attached to the sheath in three places creating little horizontal grooves. This is what gives the rectus abdominis a "6 pack" or "ripped" look when it is well developed.
The rectus abdominis is chiefly responsible for forward flexion (forward bending) of the trunk but it also helps compress the abdomen.