Core Function 101
The core is one of the most popular, overly-dissected, and most misunderstood areas of the body when it comes to training. Core strength (or lack thereof) is blamed for all kinds of injuries, ranging from lower back pain or neck issues, to hip stiffness, and tight hamstrings. The core gets no shortage of the blame when it comes to pain and performance.
It is not my intention to imply that the core is not a big factor when it comes to pain or movement dysfunction. Almost any time you experience pain or difficulty with certain movements, core dysfunction WILL be present. This is because all movement is reliant on some level of core activity. However, many times we fail to distinguish between core “strength,” and core “function.” There is actually a significant difference, and we need to ensure our core muscles function well before worrying about strong they get.
We also need to understand what the “core” actually consists of, because it seems that many of us have different ideas of what the core actually is. In my personal opinion, I think it can be helpful to consider the core as anything that isn’t the extremities (arms and legs). If you want to get more specific, the core consists of the ribcage, the pelvis, and all the muscles and connective tissues on, around, and in between. It’s more than just a few superficial muscles that are often the target of many gym-goers and dieters.
Intrinsic Core Muscles:
diaphragm
pelvic floor (this is a collection of muscle, but i won’t bother naming them all)
transverse abdominis
multifidi intercostals
hyoid muscles
jaw muscles
When it comes to the function of the intrinsic core, we have two primary focuses. Firstly, we want to ensure that we have the ability to breath well in multiple positions. If we lose our ability to breath during any given movement, whether we unintentionally hold our breath, make our breathing more shallow, or it becomes predominantly mouth-based as opposed to nasal breathing, chances are likely that our intrinsic core is not functioning as optimally as it should. Secondly, our focus should be on having the ability to create adequate intra-abdominal pressure in order to brace properly for certain exercises and movements.
Extrinsic core muscles:
Rectus Abdominis (6 pack muscles)
abdominal obliques (internal, external, posterior)
spinal erectors
Lats glutes
The extrinsic core has a slightly different job. Primarily, our extrinsic core works to prevent unwanted movement from occurring, creating a stable foundation for the arms and legs to move on. Because our extrinsic core muscles are larger and can generate/resist more force, they serve to provide the most gross overall stability. Secondly, the extrinsic core works to facilitate coordination and force transfer between our limbs, helping us to do things like throw, kick, punch, run, jump, etc. while keeping our spine, ribcage, and pelvis in optimal and stable alignment.
The extrinsic core builds off of the initial pressure and internal stability created by the intrinsic core. The synergistic relationship between the extrinsic and intrinsic core ties everything together.
Core Stabilization Strategy #1
Bracing w/ Breath Holding
In training, I coach core stabilization differently depending on the exercise we are doing. If heavy deadlifts or other axially-loaded lifts are on the agenda, bracing and holding the breath is important. Our primary goal when we are moving heavy weight is to ensure the stability and safety of the spine under load. As well, the stiffer we can make our trunk, the less likely we are to have an energy leak or breakdown elsewhere.
Intra-abdominal pressure is key when it comes to lifting heavy things without getting hurt. First and foremost, the ability to create optimal intra-abdominal pressure relies on the intrinsic core functioning properly. This means we need to ensure that the muscles involved are working properly, which can be hard to be sure of without having a means of accurately testing them. See the diagram below for a visual aid in breathing mechanics and pressure.
In order to create good intra-abdominal pressure, we use a deep, sharp inhale to expand the lower ribs. The goal is to create pressure and tension 360 degrees all the way around the trunk. Often times the anterior ribs and belly move too much, while the posterior and lateral ribs don’t move enough. This is a common blind spot for a lot of us. Another common mistake is breathing upwardly, having the upper ribs and neck do a lot of the work. Our focus should be on the lower ribs, lower back, and belly. Taking in a big inhale will create pressure outward against the abdominal wall. If left unbalanced, we run the risk of potentially getting a hernia, prolapse, or muscle strain.
One way I like to explain the concept of the core is to think of it almost like a soup can. The diaphragm is the top lid, the pelvic floor is the bottom lid, and the abdominal wall is the cylindrical tube. Creating optimal intra-abdominal pressure relies on maintaining alignment of the top and bottom lid, respectively. If the ribs flare too much, the diaphragm functions less efficiently. If the pelvis tips too anteriorly or posteriorly, the pelvic floor muscle function less efficiently. Muscles not functioning efficiently cannot utilize their maximal strength capabilities, and we will be weaker because of it.
We need to counteract the tension pushing outward with tension pushing inward. This is where the function of the transverse abdominis is important. The TVA acts as a natural weightlifting belt. When engaged, it creates a cinching, corset-like effect, which helps to balance out the tension surrounding the abdominal wall. The internal pressure created by our breath facilitates tension outward, while the contraction of the TVA and other abdominal muscles facilitates tension inward. This tension relationship is what bracing is all about, and provides us optimal stability for the ribcage, lumbar spine, and pelvis.
So in a nutshell, bracing for the purposes of heavy lifting goes something like this:
Sharp quick inhale through the nose.
Lower ribs expand, and trunk musculature eccentrically loads.
Holding the breath and maintaining pressure and tension, initiate lift.
Maintain tension of intrinsic and extrinsic core muscles.
Slowly release breath as you finish the concentric portion of the lift.
Repeat for each rep.
Core Stabilization Strategy #2
Isometric Tension w/ Breathing
When we are performing an exercise like a plank, an isometric, lower-intensity stabilization exercise, we still want to brace, but we don’t want to hold our breath, and we don’t necessarily need to over pressurize or bear down. The goal with a drill like this is ensure that we can use our intrinsic core to facilitate efficient breathing, while simultaneously maintaining appropriate tension through the extrinsic core to prevent unwanted movement. It can often be difficult to do one without the other. Many times when our core is not functioning efficiently, we will hold our breath as a means of trying to create stability. Why is holding your breath not a good thing when it comes to stabilization? I mean, we just finished talking about bracing and breath holding being a good thing to protect our spine, right? Well, yes...when we are lifting inordinately heavy objects. Breathing mechanics are less important than the structural integrity of your spine. Lower-intensity activities require less overall aggressive stabilization strategies.
Outside of some specific circumstances (heavy lifting, diving underwater, or the avoidance of inhaling something toxic are good examples), we should never hold our breath. Human life itself depends on the intake and utilization of oxygen to fuel cellular processes necessary for systemic function. In the hierarchy of needs, oxygen is the top dog. We can survive days without water or weeks without food, but only minutes without oxygen.
Breath holding is a protective mechanism. It is a reflex associated with the fight or flight response. High stress situations increase our breath-holding tendencies. This is often why I will see high-anxiety people being inefficient breathers. Even if it’s not holding your breath, it might be making your breathing more shallow. Mouth breathing as opposed to nasal breathing is also associated with the fight or flight response. Whether we see a bear in the forest, anticipate being submerged underwater, or feel unstable balancing on the edge of a cliff, shallow breath or breath holding tends to be present. This tells me that if my client is doing a plank and they can’t do it without holding their breath, their nervous system does not feel safe; it is triggering a fight or flight response. Not only that, but it tells me that their core is not functioning well in that position, and they are attempting to use holding their breath and locking down their diaphragm as a means of compensating for a lack of core function elsewhere.
In static positions, we need the intrinsic core to keep on ticking, facilitating smooth and efficient breathing, while the extrinsic core muscles can provide the tensional stability we need to prevent unwanted movement from occurring. You should be able to hold a plank, feel your core muscles working, all the while being able to have a conversation with someone and breath freely and effortlessly. If you can’t, your core function can stand to be improved.
How well do you think a marathoner would perform if their hips, pelvis, and core were so unstable that they solely relied on shallowing their breathing to create stability? They might become more stable and provide for structural stability for the hips, pelvis, and core, but an endurance athlete who can’t breathe efficiently won’t be setting any records.
Core Stabilization Strategy #3
Abdominal Tension w/ Synced Breath
Performing a more traditional exercise wherein we are moving through concentric (muscle shortening) and eccentric (muscle lengthening) phases of muscular contraction, like a pushup, we want to utilize a similar strategy as we would with a plank, but with the added component of syncing our breath with the concentric and eccentric phases of contraction. Generally, we want to exhale during the concentric phase and inhale during the eccentric phase. I’ve found through neurological testing that if you do the opposite, you are actually creating a inhibitory effect in the muscles you are working, which is obviously not optimal. I’ve also noticed that breathing freely, independent of syncing motion with your breath is typically fine as well. Just make sure that you do not inhale during concentric phases of movement. Not much else to say with this one.
Wrapping Up
As I’ve hopefully illustrated relatively clearly, we want to breath, brace, and stabilize differently depending on the movement or exercise we are performing. Outside the context of training or lifting, we want our core to function reflexively. There is no need to have to be hyper aware and consciously engaging our core for everything we do all the time. The core should be able to do it’s thing without too much conscious input. It should support our spine, provide a stable foundation for our extremities to move on, and allow us to move in a variety of contexts while maintaining proper breathing mechanics. Different scenarios call for different core stabilization strategies.
The core is the foundation for all movement. Breathing is the foundation for the core. Master breathing, master the ability to create intra-abdominal pressure, and master the ability to stabilize your body in various positions and various movements. Ultimately, pain and performance are reliant on a functional core.