Working the Core

In the gym, I hear the term “core” used a lot. “I have such a weak core,” or “my abs are so sore from that core work we did two days ago.” But often, no one has any idea what their “core” actually is. When we do core training, it’s important to differentiate the core into two categories – Stabilizers and Movers.


These are the important slow-twitch muscles that help to stabilize your spine. They are made up of slow twitch muscle fibers that enable them to maintain contraction for longer periods of time without fatigue. Stabilizers are made up of several muscle groups that keep your back in alignment. They are also the muscles that hurt when you lift a weight with your back rounded. But which muscles are these, exactly? I won’t get into the scientific names (you can look these up if you want to). For now, just know that they are the small muscles of the lower back and the central spine.

These stabilizers are key for maintaining proper posture and for avoiding injury such as disc herniations. Since such injuries are usually caused by a combination of rotation, side-bend, and/or flexion or extension, the stabilizing core can play a big role in restricting those motions for injury prevention. Automatic engagement of these muscle groups should occur when performing activities such as lifting, carrying, or even opening a door. When it doesn’t, it is usually due to mechanical restrictions in the lower back or pelvis, or over-activity of other muscles. Interested in extra work on your Stabilizers? Exercises such as planks are the answer.


Movers aren’t attached directly to the lower back or the central spine. They are large, because their job isn’t to hold the small bones of the back in place but to provide locomotion. They are responsible for movement such as trunk flexion or side-bend. These muscles are integral for movements like sit-ups, toes to bar, and supermans. Many of them are also slow-twitch muscles, which sometimes cause them to get tight and overactive. If you attend crossfit classes regularly, many of the movements you already do help to strengthen your Movers. If you feel like you have a weak core, accessorizing with stability work (the Stabilizers rather than the Movers) may help you better achieve your core strength goals.

A note of caution: Watch many people do deadlifts, wall-balls, squats, or even bench presses, and you are watching a back injury in the making. The reason? They are using their stabilizers to move the weight. When they do that, the stabilizers are not free to keep the back stable and neutral. They are being misused to move things, and thus taking them out of their stabilizer role. This allows the back to float. Further complicating matters, this also exhausts the stabilizer muscles so the back is in jeopardy long after the exercise is performed.

So, what does this mean in practical terms when performing an exercise? Here are some basic rules derived from this:

  • Keep the back neutral. Don’t arch or bend the back to gain leverage in lifting. When lifting weights, this defeats the exercise–so, no purpose is served. No matter the reason for lifting, bending the back to aid in the lift will strain the stabilizers.
  • Think leverage. Think of your body as a collection of levers. What are they prying against? If you are performing an exercise such that the force centers on your stabilizer muscles, your form is wrong.

We do core work quite often in crossfit, in just about every workout, and not just when performing sit-ups, v-sits, and toes-to-bar. Now make sure you’re effective and safe when doing this core work. Coach Pete wrote a recent article about quality over quantity and perfecting your form. The message here is the similar. Don’t rush. Focus on what you’re doing. Use your stabilizers to hold things in place, and use your movers to move things.


Coach John