At this point many of you may be asking, “what is midline stability anyway?”.  Midline stability is your ability to maintain rigidity through your spine and hip through a full range of motion.  In other words, your ability to hold your hip and spine completely locked in place while your body moves.  We refer to this section of the spine locked into the hip as the “core”.  Now, if you’ve ever watched late night television infomercials they would have you believe that the core is all about the abs, but this is only partially true.  In fact, while a six-pack is a fine goal in itself it will not necessarily lend itself useful to true midline stabilization.  Furthermore, crunches and traditional sit-ups have little to no affect on an athlete’s ability to achieve midline stabilization.  Why?

Crunches and even sit-ups are a concentric action of the abdominals.  That means that they require a contraction of the abs where the abdominals become shorter.  You can picture this when you see someone do a crunch and it’s clear that their belly button gets closer to their sternum.  We call this trunk flexion.  But how often do you find yourself in a real-world situation needing a large amount of strength in order to flex your trunk or bring your sternum closer to your belly-button?  It’s not very likely.  What you will often find is the necessity to be able to “brace” yourself in order to pick up a heavy object, lift something overhead, throw an object, etc.  This act of bracing is an isometric contraction, which means that as we squeeze our muscles tighter they do not change in length.  You can see this in a proper ghd sit-up where as the athlete lays back their abs remain tight and as they sit-up through the aggressive extension of their legs their belly button stays relatively the same distance from their sternum, unlike in the crunch.  We find that this isometric contraction, or the ability to maintain our midline, has infinitely more carry-over to the things that we do in real life.

In CrossFit we move heavy loads, long distances, quickly and we use functional movements to do this.  By definition, functional movements are those that are initiated from the core and radiate to the extremities.  If that core is not solid then power is lost as it is radiated and in some instances the core can be so weak that it can be damaged in the movement.  Picture the I-beams that hold up our shop.  If we changed them from steel to jello you wouldn’t feel very safe standing under the roof.  The same applies to your own body.  If you’re trying to move a heavy weight quickly but the foundation with which you’re trying to initiate that movement cannot maintain it’s own integrity, you will suffer a loss in power and potentially the inability to perform the movement.

This concept of midline stabilization applies to absolutely every movement we perform in AND out of the gym.  It’s one of the main reasons why ex-gymnast pick up on CrossFit so quickly and tend to make great athletes in general.  They’ve been drilling this since they were children.