“Six pack”, “washboard abs”, “abs of steel”, or “rock hard abs” are all names for the rectus abdominis (RA), or abs for short. As a physical therapist, I have been trained to think about function, not just aesthetics, and in doing so, have come to learn that the abs are not as important as most people think.
Sure they will stop a punch from decimating your organs, or make all the girls on the beach “ooh” and “aah” with delight, but will they really improve your sports performance? The answer may surprise you. But first, the boring stuff…
Anatomy: The RA is actually two muscles on both sides of your abdomen that run from your pelvis to the bottom of your 5th-7th ribs. The muscles are connected in the middle by the Linea Alba, and the horizontal lines are created by things called tendinous inscriptions.
[Fact: Six visible separations are the most common anatomical layout of the RA, but some people are born with eight or even ten separations, and it is not possible to naturally change the number after you are born.]
Function: The RA prevent extension of the trunk, flex the trunk (forwards and to the side), assist in breathing, tilt the pelvis, and assist in the valsalva maneuver. There is no research supporting the RA as a trunk rotator, and this is where the abs lose their luster in the physical therapy world; almost all sporting movements actually combine flexion or extension of the trunk with rotation.
Rotation is actually provided primarily by the external and internal oblique muscles, not the RA. Take a baseball swing for example. Your body requires trunk rotation, therefore, to increase your functional strength for this activity why would you perform an abdominal crunch laying on the floor? In my opinion, it is much more important to target rotational muscles in a standing position to increase your functional strength.
Posturally, the abs do help keep your trunk upright, but they work as part of a team to do this with the TvA, obliques, multifidi, erector spinae, etc, so the RA are not the only piece to the postural puzzle either.
Most importantly for those interested in performing ANY amount of abdominal work; to properly strengthen your RA, the spine should be held in a neutral position. This is not done by having your “gut” sucked in and spine flat, or bracing/holding your breath. To find your neutral spine, check out this video (really quick and easy way to figure it out).
Fortunately, the functional training movement is already out there, and it is changing the way “abs” day looks in the gym. As stated earlier, the “abs” are needed to protect the organs from impacts as in boxing, or to prevent forceful extension of the back, and keep the spine in good posture. It is very rare that someone would need to forcefully flex their abs while laying on their back during any sporting event (except wrestling, and MMA). And to steal a quote from Mike Boyle, “You’re probably not very good at your sport if you find yourself on your back during the middle of a game”.