How Your Spine, Low Back & Core Work Together

I often talk about how your spine, low back, and core muscles work together to support movement, stability, and strength.  But here we’re digging deeper to look at the interconnections. How do they actually work together? And do we need to strength-train them like we do our arms or legs?

We’ve covered what the muscles of the spine and core are. But a deeper question still hangs in the air: how do they all actually work together?

The short answer is ‘not exactly’, but let’s start by looking at the role of these different muscle groups.

Multifidus and your spinal communication system

Let’s talk first about multifidus, and the other small muscles that span the transverse and spinous processes of the spine. These aren't your power generators. Instead, they’re densely wired with neural structures, and their primary job is to offer postural feedback, not strength.

This deep layer of ‘stabilisers’ act as a communication system between your spine and your central nervous system (CNS). They detect micro-movements, subtle rotations, shifts in posture, and feed that data back to the CNS. This allows the brain to adjust, signalling the appropriate surrounding muscles to contract or release as required.

So, while they might contribute a level of spinal stability, much like ligaments their main job is not to generate movement, it is to monitor and adjust for it. Their control is reflexive and unconscious. You don’t ‘feel’ them contracting like you do a bicep during a curl. So, while you can train these muscles to improve stability, you certainly wouldn’t do it with reps and sets of load-bearing work like you might for that bicep.

The role of the core and reducing ‘energy leaks’

Now, let’s shift to the core - the middle and superficial muscle layers.

Here, the job changes. In fact, the key role of the core is to transfer force and stabilise the spine. It doesn’t matter whether you're throwing a ball or deadlifting a barbell, force starts in the ground (via your legs), moves through your torso, and exits through your arms. And it’s the core that helps to make sure that happens as it should.

If posture is maintained, load is distributed evenly around the torso. Imagine 100 units of force being shared equally: 25 to the front, 25 to the back, 25 to each side. That’s what happens if you maintain the correct posture during a movement or exercise. But if you break that posture, say you fall into flexion or rotation at the wrong time, then the load concentrates in one area. And that might mean the spine ends up bearing more than its fair share.

This is where the idea of "energy leaks" comes in. If the torso collapses under load or rotates poorly, then force dissipates. Instead of 90% of the power generated through the legs reaching the target (e.g. the ball or the bar), you might only transfer 60% or less. The rest is lost.

Intra-abdominal pressure – the whole is greater than the parts

To counter thee ‘energy leaks’ – because it’s easy to break posture, the core offers an additional tool for stability. It generates something called intra-abdominal pressure. This is effectively a contained force pushing outward, that is stabilised by the contracting abdominal wall. By maintaining inter-abdominal pressure, we create stiffness through the midsection and support the spine under load.

From a mechanical perspective, we might compare this to hoop stress in engineering. That is, outward pressure resisted by circular tension. Think of a pressurized steel tank or a carbon fibre. In the example of carbon fibre or plywood, we see a lattice of fibres laid down in opposing direction creating more integrity and strength. The core works like this. It’s a crisscrossed mesh of different layers – of muscles and fascia creating a structure that's strong, flexible, and robust in multiple directions.

But that is why training the core isn’t the same as training the limbs. Limb muscles, like the quads or biceps are long and linear, after all, they’re designed for power and movement. The core, in contrast, is layered, multi-directional, and stabilising. It’s not a ‘prime mover’, as discussed above it’s a ‘force transmitter’.

So, what does this mean for training your spine, low back and core?

Understanding the above helps us approach core training in a better, more effective way.

The core’s job isn’t just to resist movement. It’s to manage load, transfer force, and maintain spine stability under dynamic conditions. When lifting, for example, or throwing or rotating. When we lose posture, we lose force. When we maintain it, we are able to channel our power through our legs, core and arms to where we need it.

Subscribe to my YouTube channel so you won’t miss out on the next part of this, where I’ll be exploring how to train the core to do exactly that, by focusing less on muscles in isolation, and more on the whole.

Meanwhile, if you want to build core strength and stability, click here to receive monthly education and advice.