Unite Fitness

The Critical Six Pack Muscle

– Coach Evan Shaulson

“What should I be doing to get a six pack?” is without a doubt, the most common question I get as a trainer.  This guide is the answer to that question and in the longer linked article there is a set of great ab workouts for every experience level.

Far too often, people start some “six pack program” without any understanding of how or why it works.  As a result, when the program gets boring or results start coming slower, they stop doing it.  This guide will serve as your defense against boring and ineffective core training.  Once you understand the principles, you can mix and match different styles of core workouts to keep your exercise regiment dynamic and engaging.

Anatomy of a Six Pack

Having a strong, and shapely midsection is the result of combining a low body fat percentage with a set of well developed abdominal muscles.  The body fat issue is one for a separate article.  Muscle development however, is exactly what we’re talking about here.  Having said that, there’s much more to a solid core than just the rectus abdominis, which is the group of square shaped muscle tissue often referred to as the “six-pack”.  The often-overlooked components of the core are the ones that are the most important when it comes to strength, structural integrity and posture.  The deeper, and therefore less visible muscle groups in the midsection are both the root of your entire musculoskeletal system and the primary protectors of your internal organs.

Developing a strong and stable core requires a combination of different training modalities to target each of the groups of abdominal muscles.  Each of these groups serves a unique physical function and responds to an equally unique training stimulus.   Let’s break that down a little further.

The Transverse Abdominis: Your “Deep Core”

This sheet of muscle rests under the other abdominal muscles and wraps around your torso to keep your entire mid-section stable.  Often referred to as the “deep abdominal wall”, this muscle is the key to strong core and a shapely six-pack.  A primary function of the transverse abdominals is to protect your internal organs by keeping the midsection tightly wrapped around the spine.  So what happens when the transverse abdominals are underdeveloped?

Well, you’ve probably seen people with a very well defined, but strangely protruding six-pack.  This is the aesthetic consequence of weak transverse abdominals that are failing to hold in the more external tissue of the midsection.  To strengthen the transverse abdominals, the most effective exercises are plank-like holds with the added stress of moving extremities.  If your belly button is being squeezed back towards your spine, you’re working your transverse abdominals.  Exercises like side planks, ab roll outs, TRX knee tuck planks, and most hanging ab exercises are great for strengthening the transverse abdominals.

Internal and External Obliques

The obliques are the muscles that run down the side of the torso and connect with each other to give you the strength to twist and turn around your midsection.  The two primary functions of the obliques are to provide the strength for torso twisting and to hold the rib cage stable at the proper angle.  The external obliques wrap around your midsection and connect with each other in the middle of the torso running in one direction, while the internal obliques run in the opposite direction.  This creates a sort of corset effect with the obliques wrapping around the deeper, transverse abdominals.  To exercise the obliques, twisting movements as well exercises that require holding the rib cage down and stable are the most effective.

Rectus Abdominis: “The Six Pack”

This set of bilaterally paired, square shaped muscles runs vertically up and down the torso.  The rectus abdominals connect the pubic bone and the rib cage together and are responsible for curving the spine behind it to create a folding action at the midsection.  This is the outermost group of abdominal muscles, which is why it’s visible over the obliques and transverse abdominals.  Any exercise that creates a crunching motion will stimulate these “six pack” muscles.

The biggest mistake that people make when exercising the core is to spend too much time and effort focusing on the rectus abdominis.  Your six-pack won’t look good, even if you’re already lean.  The key to a great set of abs is strong transverse abdominals and obliques to keep the core tight around the spine and internal organs.  Only with that tightness can you add well-developed rectus abdominal muscles to create an aesthetically pleasing six pack.