Starting Strength

Abs

by Mark Rippetoe

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“Since the basic nature of correct ab function is isometric, the exercises in which the abs perform this function will provide exercises for the abs as well. This may seem childishly apparent, yet virtually every strength coach adds extra concentric/eccentric ab work to the program anyway. The thinking must be that just squatting, deadlifting, pressing, cleaning, snatching, chins, and barbell curls – all of which involve trunk stabilization as a critical performance component – do not provide sufficient ab work by themselves. I disagree.”

In every weight room in all the countries of the world since the dawn of training with weights, the single biggest distraction from the actual task at hand has been abs. Or rather, an obsession with/ misunderstanding of the biomechanical role of/misunderstanding of the way to train abs. More people, including me, have wasted more time/incurred more injuries doing/gotten very little out of training the damn things than anything in the whole training repertoire except biceps. Some of the things I’m about to say will be met with a lot of disagreement by conventional wisdom exercise-science types and PTs, as well as virtually everybody that trains for appearance. I don’t care – I have to get this off my chest (Atonement? A guilty conscience for having trained lots of people incorrectly? An attempt to come to grips with years of having been wrong?) and perhaps in the process I can be of use to some of you. We’ll see.

First, by “abs”, I mean the muscles that surround the abdomen. I don’t just mean the rectus abdominis, the group in the front that everybody identifies with the term “six-pack” (that I never use), the most graphic visual evidence of both low bodyfat in most people and our remote connection to phylum anellida through its evident septa that separate the muscle into repeated segments. I refer to abs when everybody else refers to “the core” because I insist on being difficult, contrary, disagreeable and out of step with the infomercial people. This is the way I learned it, and I see no compelling reason to update. So in this article “abs” means the rectus, the internal and external obliques running across the lateral aspect of the abdomen, the transversalis (or transversus abdominis), and the muscles of the floor of the abdominal cavity.

Second, the abs stabilize the spine, meaning that they maintain stable if not rigid intervertebral relationships under compressive or shear (moment) loading – that is their primary physical function in a biped. We have been placed under the impression that the primary role of the abs is display to other humans in either courtship ritual or as a means of evoking envy, and this temporary cultural bias has not proven useful to many of us.

Stabilizing the spine is an extremely important thing to do when working or training, since the force generated by the muscles that extend the hips and knees is usually transferred to the external environment through the arms and hands (in the case of the squat the bar is supported by the trunk itself ), which means that the spine is the bridge connecting the force-producing musculature to the task to which it is being applied. This bridge must be rigid – stable enough that as force is applied along its length it pretty much all gets to where it should be transferred, with none absorbed by the bridge itself. Or the spine can be thought of as a wrench handle, the thing that connects the bolt to the turning force. A quick review of all the tools commonly available shows that none of these wrenches are equipped with a rubber handle, since force is quite inefficiently transmitted between these two points by a flexible segment, and force transmission is the wrench’s job. The job of the muscles that stabilize the spine is producing a condition in which force is efficiently transmitted along this potentially moveable column of bones by making them immoveable, so that this potentially flexible column of bones functions like a tempered steel shaft instead of the resolve of a politician.

When you deadlift, for example, you consciously set the lumbar curve of your spine before you pull, you take a deep breath, squeeze everything tight, and push the bar away from the floor. The setting the- lumbar-curve part is accomplished by the posterior spinal muscles – the erector spinae group. The squeeze-everything-tight part is abs. This is when they get recruited into the pull, and their job is to reinforce from the anterior and the lateral the position established by the posterior spinal muscles. You set your back with your back muscles, and then you reinforce this position from the front and sides with your abs. Some hyperflexible people are capable of getting into a position of spinal overextension. For these people an active focus on ab contraction is necessary for positioning. Most of us find that when we concentrically squeeze the lumbar into extension, we end up in the right position to pull. This ab squeezing makes your trunk into what is essentially a rigid cylinder that surrounds and supports the spine, the effect being that of a hydrostatic column between all points along the contracting abdominal wall and the spine transmitted through the hydrostatically uncompressible gut contents. The force of contraction transmitted through this fluid medium braces the spine into the position set by the back muscles until the moment force of the load overcomes the lifter’s ability to stay in position. In order that this job actually gets done by the muscles whose job it is to do it, they have to function isometrically. Let’s review: muscles can produce force by acting on a load through the skeleton in three ways. They can shorten under a load, termed a concentric contraction (I know that sounds redundant, but the conventional terminology is thus, and I must draw the rugged-individualist line somewhere). They can lengthen under a load by controlling the rate of lengthening with their opposing contractile force, termed an eccentric contraction. And they can just maintain the same length and therefore maintain a stable, rigid relationship between the skeletal components; this is termed an isometric contraction. Depending on where the muscles are located, their primary function is either concentric/ eccentric or isometric. The hip and leg muscles’ primary function are to open and close the knee and hip joints in a variety of movements, and are therefore primarily the concentric/eccentric types. They function isometrically when you stand still, but standing still is not a primary activity to which we are adapted – at least it shouldn’t be.

Conversely, the abs’ job is primarily isometric, since spinal stabilization is their principal task. If the skeletal relationships they maintain are motionless, then their primary function is to exert force while allowing no position change, and to do this they must remain the same length under whatever load the spine must be stable against. Thus isometric contraction is their principle mode of action. They can be pressed into service to do a situp, acting concentrically/eccentrically to flex the spine while you are lying down, but it’s not their “normal” function, the one they have developed over millions of years to accomplish. We haven’t been doing situps that long – only since they were invented by Joe Weider back in 1980 – hardly long enough to have changed our inherited muscle physiology to accommodate him. Abs are supposed to keep the spine rigid, and this has some rather important implications for the way we have been thinking about training them to do this function.

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