I'm going to go out on a limb and say that unless you have been living under a rock for the past few years, you have heard somebody tell you they really need to work on their "core". It is a constant hot topic in the fitness and physical medicine fields, but have you ever stopped to think about what the term "core" really means and why it's important. My guess is that when I use the term core, the first thing you picture is a set of abdominals (or an apple, and if that's the case, you really need to read this post). In this article, my goal is to identify the anatomy that makes up your core, explain its function and also why it plays a critical role in both pain and performance.
Picture your core as a big box made up of your diaphragm on top, pelvic floor muscles on the bottom, multifidi (small muscles along your spine) in the back, and ALL your abdominals on the front and sides. Together, these structures should work in concert to make a cylinder-like structure that we refer to as your core. This is illustrated by the image below.
What is the purpose of this particular body region? I’m glad you asked. The main role of your core is to create spinal stabilization, in turn creating a solid, yet dynamic base for other muscles to generate movement from. Here’s how it works. When you take a proper breath in, and your diaphragm drops, your pelvic floor musculature co-contracts along with your abdominals. This acts much like a piston in your car, generating an increase in intraabdominal pressure (IAP). The increased IAP along the front side of your spine, works with the deep spinal musculature on the back side of your spine to offer stability. You see, you don’t have much for intrinsic anterior musculature along your spine. You have a big abdominal cavity full of guts. Therefore, increasing IAP makes up for that by acting like a big beach ball being pressed tightly up against your back. You have now created the solid anchor that is a pre-requisite to all quality extremity movement.
Now, let’s discuss extremity movement. For the sake of simplicity, we will use the lower extremity and the Psoas major muscle (It is important to note that during movement, your muscles do not work in isolation, but rather along with other agonists and antagonists, but for this demonstration we are focusing only on the action of one muscle.). Your Psoas major is attached to your lower vertebrae on the proximal end, and the upper part of your femur on the distal end. It acts to flex your hip joint. So, when your Psoas contracts, it will pull on your femur and your spine. If you have good core activation and therefore spinal stabilization, your Psoas has a solid anchor point to “pull” from, allowing the Psoas to properly perform its job. This will help to keep your hip joint centrated throughout its range of motion and the Psoas will be more efficient. However, if you have poor core activation, your Psoas no longer has a solid anchor point and may cause anterior shear of the spinal vertebrae as they are no longer centrated as well as possible decentration of the hip joint. In addition, when a muscle cannot perform its job correctly, your body may recruit additional muscles to help perform the task. This is called compensation. Compensatory movement patterns are likely to aid in de-centration of joints. A centrated joint allows for optimal load transference of muscular forces across the joint with minimal mechanical stress on the passive structures such as ligaments, capsule, cartilage, and joint surfaces. A centrated joint is one that is most congruent and has the least friction. A well centrated joint can work all day long and suffer very little wear and tear. A de-centrated joint now has increased friction and stress, leaving it more likely to wear sooner causing degeneration and pain.
Your body likes stabilization during movement. It will do whatever it has to in order to create it. Without good core activity and spinal stabilization, your body will use alternative methods to create it. We already touched on compensatory movements, or recruiting additional musculature to aid in a movement. In the case of your spine, if you are not generating deep spine stabilization, your larger, superficial spinal extensors will take over causing increased compression and stress on the intervertebral joints. This is called the extension/compression strategy. Another way to create stability is to increase muscle tone. Think about those pesky “tight” hamstrings. If you have poor core activity, your hamstrings will likely be tight as a backup attempt at lower extremity stability. These attempts by your body to create stability help to explain how poor core activity can lead to dysfunction, degeneration and eventually pain.
The last part of this post will focus on how your core is tied in with performance. To review, proper core activity leads to good quality stabilization. Good quality stabilization allows for proper muscle activity around joints. Proper muscle activity around joints means greater mechanical advantages of muscles and greater efficiency. Greater output and efficiency means greater performance. Pair that with your joints being under less stress, and now you not only have greater performance, but also less injury risk.
I would hope that you now have a better understanding of what your core is, how it works, and how it can play roles in pain and performance. In a follow-up posts, I will cover how to determine whether or not you have good core activity, and how to properly train/strengthen your core.
Have a great week and please feel free to contact our office with any additional questions.