Abdominal Musculature Breakdown and Functions

The abdominals are composed of the rectus abdominis and the lateral abdominal muscles known as the transversus abdominis, and the internal and external obliques. The rectus abdominis runs from your sternum to your pelvis and essentially helps pull your rib cage and your pelvis closer together. The transversus abdominis acts as a natural weight belt essentially holding your insides in, and stabilizing your trunk. The internal and external obliques work to rotate the torso and stabilize the abdomen. The rectus abdominis is the actual visible “six pack” that you see in someone with well-developed abs and a low body fat percentage. However, the lateral abdominal muscles are also very important to develop due to their role in supporting the spine and maintaining a healthy lower back. In addition, developing the transversus abdominis helps pull your stomach area inward giving you the appearance of a smaller waist. Whenever you suck your stomach in (like a guy at the beach trying to hide his gut), you are using the transversus abdominis to perform that movement.

The action of the rectus abdominis can be initiated by crunching the upper body up or by crunching the lower body up. A popular myth is that people think that the upper abs and lower abs can be worked separately. The fact is that you cannot isolate the upper or lower
abs. The rectus abdominus is one muscle group and the entire length of the muscle group is activated whether you’re pulling the upper body up or pulling the lower body up. With that said, it should be noted that it is beneficial for you to work the abs from a variety of different angles to ensure maximum muscle fiber development throughout the entire abdominal region.