Getting the tension of your core muscles “just right” to overcome back pain and return to full activity


As an active teenager who devoured all food within my grasp, I was never sure if I should commend Goldilocks as my model of bold food consumption, or if I should despise her outright thievery of someone else’s delicious breakfast. Looking back, I’m pretty upset that she ate the bears’ breakfast; that is definitely on my list of crummiest things someone could do to me. However, Goldilocks is quite wise if we apply her selectiveness to core tension for spine stability.

We’ve likely seen and heard an abundance concerning core muscles. But we’re not talking about trying to show off any abs here; we are talking about motor coordination of your core muscles to increase spine stability. Sounds exciting right? Well, do you find yourself holding your breath in anticipation of that twinging back pain when you roll out of bed, or stand up from your chair, or rise up after putting on your shoes? Then our journey together for the next few minutes will be exciting. Time to put an end to that pain-fearing anxiety!

What is Spine stability?

We could talk about lumbar stability for days…and many researchers and clinicians do. We’ll make this much quicker here, and it’s easiest to understand by defining the lack of stability. Lumbar instability refers to aberrant motion, typically a shearing motion, of spinal vertebrae that leads to pain. We would then say someone’s spine exhibits stability if they prevent this shearing motion and subsequent pain.

VPAC: the key to stability

Now, what in the world is VPAC? This is a nice little acronym for volitional pre-emptive abdominal contraction. A bit of a mouthful. Just think of it as the activation of core muscles to promote spine stability. The activation of these muscles promotes stability through two main mechanisms: a mechanical mechanism and a pressure mechanism.

Mechanically, the core muscles act as a broad, internal belt that pulls all the tissue tight from the spine to the belly. This mechanical tension and support provide crucial stability at your spine during any moving or lifting tasks. 

the transverse abdominis is a spinal stability key muscle
“…the core muscles act as a broad, internal belt…”

To understand the pressure mechanism, let’s picture a perfectly matched tug-of-war stalemate. Both sides are pulling with perfectly equal force, and this creates an incredibly strong tension on the rope. The tensioning of core muscles (which includes your pelvic muscles and diaphragm) dramatically increases your intra-abdominal pressure, but the force of this pressure is counteracted by the mechanical force of your abdominal flexor muscles. This creates a force stalemate leading to a perfectly tensioned and stabilized system around your lower spine. (To read more about these two mechanisms of stability, check out these research studies: article 1, article 2)

spine showing muscles for spinal stability
When these forces are balanced, increased stability follows

“Too hot” and “too cold”

Many of us tend to go 100% on anything and everything we think is good. I find the same trends when it applies to core tension. We hear coaches and trainers say, “Tighten up your core!” and we just turn everything on 100% because no one has taught us anything different. 

Just like it wouldn’t make sense to activate our legs at 100% capacity just to walk (and we would look like a teetering robot), it doesn’t make sense for us to activate our core muscles at 100% for most of our activities either. I also see patients aggravate their back pain when they activate their core 100%. These poor souls think they are protecting their back by completely tightening their core for simple activities, but they are actually hammering one of their triggers!


We also don’t want our core muscles completely off either. If our core muscles aren’t activated enough, we lack the tension we need to stabilize our spine. Proper spine stability provides a firm foundation for our legs and arms to produce power with control. Without this central stability, our extremities struggle to produce enough force to perform as needed, and we also leave ourselves more susceptible to injury at the spine. 

Neither 100% or 0% core activation is best for our spine health or task performance. Hence the “just right” lesson from Goldilocks.

Getting core tension “just right”

Finding your proper core tension is a good mix of science and art. There’s some informative research that has shown that activating your core muscles at around 20% capacity is to your greatest benefit (article 1, article 2). Beyond 20% activation, the size of your core muscles doesn’t expand any further and the intra-abdominal pressure doesn’t increase, so activating beyond that maximum is introducing unnecessary strain on your tissues and spine.

goldilocks teaching about spinal stability
That is one sneaky looking Goldilocks right there

There are occasions that will require greater contraction of the core muscles, i.e. a max barbell squat, but for most of us, this 20% rule ensures maximum movement and spinal stability with minimal strain. It continually amazes me to see patients in pain when they try to roll off my treatment table with 0% contraction and then again with 100% contraction, but then have no pain when they find their sweet spot of core contraction.

I said earlier that this was an art and a science because it takes some tweaking for each individual, but pain is a great guide in this case. I teach and cue the patient to contract their core properly. Then we perform a simple movement, like rolling out of bed, adjusting the strategy and intensity of their core contraction until they can repeatedly perform the movement pain-free. It sounds pretty simple when I write it out, but it leads to huge healing gains for overcoming back pain.

We’re not done yet 

It took a lot of strength for me to not nerd out and give you everything I have on this topic all in one article…but that would have been chaotic. So stay tuned for a lot more information coming your way about lumbar stability and core activation. Unfortunately, there is an incredible amount of misleading information concerning this topic online and in the fitness world. Fortunately, there is an abundance of informative research and clinical experience on this topic that I will regularly expound upon here. Until then, keep your core tightness “just right!”

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