THE NEURO MENTORSHIP LONG-COVID RECOVERY BLOG ABOUT US LOGIN

Next Level Neuro 
News & Education

Chronic Lower Back Pain

The Neurology of the FMS: Unlocking the Deep Squat


What if we could enhance FMS results faster, more sustainably—and actually make those changes stick?

 

When Muscles Don’t Tell the Full Story

Let’s get one thing straight upfront:

The Functional Movement Screen (FMS) is a phenomenal tool. 

It gives coaches, trainers, and therapists a structured way to assess movement quality, spot imbalances, and create smarter training plans. It’s helped thousands of professionals start with clarity instead of guessing.

But what if we could go one step further?

What if we could enhance FMS results faster, more sustainably—and actually make those changes stick?

This educational piece isn’t here to replace the FMS.

It’s here to upgrade it and give a new perspective to enhance an already well established protocol.

Behind every compensation, limitation, or poor squat pattern is a nervous system trying to keep someone safe.

And if we understand what the brain is doing behind the scenes, we can create faster change, with better outcomes.

Below, we’ll focus specifically on the Deep Squat—what can go wrong, why the nervous system might be behind it, and how to fix it fast using brain-based tools. 

And this is just the beginning.

Over the coming weeks, we’ll pull apart every FMS test through this same neurological lens—so you can upgrade your assessment game one screen at a time.

The Deep Squat, the very first FMS test—and arguably the most comprehensive. 


What we’ll explore:

  • Why clients struggle with this test (it’s not always tight calves)
  • What brain systems are involved
  • How applied neurology can unlock better movement fast
  • Real drills to try—today—that can change the squat in seconds

Let's get Neuro-Nerdy!

 

 

Why the Deep Squat Matters...(and Why It’s So Tough)

The FMS Deep Squat is a full-body assessment. 

Dowel overhead, feet forward, squat down deep.

In just one rep, you’re testing:

  • Ankle dorsiflexion
  • Hip mobility
  • Thoracic extension
  • Shoulder range
  • Core stability
  • Postural reflexes

 That’s a big ask.

And most clients don’t “pass” with a clean 3. They compensate—heels lift, torso leans forward, arms drop, or depth is limited.

Here’s the usual fix: stretch the calves, foam roll the T-spine, cue the core harder, and maybe elevate the heels.

Sometimes it works. Often it doesn’t last.

Why?

Thousands of trainers and coaches offer their “fix” for these movement issues—but more often than not, the problems return.

Clients ask why, and the answers they get are often the best that a purely biomechanical education can provide. 

But those answers aren’t always mobility problems.

At Next Level Neuro, we look at movement through a brain-first lens—because most of the issues we see in the FMS aren’t just mobility problems…

They’re brain input problems.

When you start viewing the FMS this way, the puzzle pieces fall into place.

So let’s break it down—one neural system at a time.

 

 

Movement Is a Brain-First Game

If you’ve ever stretched a tight muscle for weeks only to see it tighten back up, you know this pain.

That’s the nervous system doing its job: protecting you from what it perceives as threat.

**To understand more on threat, read here.

Here’s how it works in the squat:

  • If your vestibular system (inner ear) doesn’t feel safe with your head moving through space, your brain will limit how deep you go.
  • If your visual system doesn’t have a fixed reference, it might cause dizziness or sway, so your body leans forward or stiffens.
  • If your proprioception (body awareness) is fuzzy—especially around the ankles or hips—your brain might tighten everything up as a precaution.


This is protective behavior, not dysfunction.

That’s why biomechanical fixes alone often don’t hold.

The client might squat better after a few sessions… but weeks later, they’re right back where they started—tight, unstable, maybe in pain.

Unless we change the brain’s interpretation of the movement, the compensation comes back.

To understand the interpretation, let's give you a quick understanding of the brain systems behind the squat and what those nervous system compensations might be. 

 

 

Brain Systems Behind the Deep Squat

Let’s pull apart the deep squat neurologically. 

For every neuro drill we are going to share, there are countless others.

These examples aren’t a one-size-fits-all solution—they’re starting points.

Each client’s nervous system is unique, and the real magic lies in how we assess, choose a neuro drill, and reassess.

Want to learn how we tailor this process? Watch our free masterclass here.

Below are the four brain systems we most often see influencing the Deep Squat Assessment.

 

 

1. Vestibular System: The Inner Ear that Balances You

The deep squat changes your head’s position quickly.

You’re moving vertically, shifting center of gravity, and sometimes even looking up (with the dowel overhead).

The vestibular system—especially the saccule, which detects up/down motion—has to process all of this.

If it’s not calibrated, your brain might not trust the motion.

So it throws on the brakes:

  • Tightens calves to limit depth
  • Pulls you forward to stabilize
  • Braces hips or hamstrings to keep you from falling 

If someone says they feel “off” or “unstable” at the bottom of a squat, you might be looking at a vestibular issue.

Why it matters:
The vestibular system (your inner ear) tells the brain where your head is in space and how it's moving—especially in response to gravity.

In a deep squat, your center of mass drops, your head position changes, and your body moves vertically—all of which place high demands on vestibular input.

If the system is underperforming or overwhelmed, your brain may respond with:

  • Bracing or tightening muscles to “guard” against instability

  • Shifting weight forward to avoid perceived falling

  • Restricting depth or freezing in mid-squat

In short: if the brain doesn’t trust its balance system, it won't allow full, free movement—no matter how mobile or strong your client is.

 

Quick Neuro drill:

Saccule bouncing: Try 20 seconds of gentle vertical bounces (like mini hops or heel raises). This stimulates the saccule.

Then retest the squat. You’ll often see better depth and control immediately.

Why it works:
The saccule, a part of the vestibular system, detects vertical movement and gravity.

By stimulating it, you help the brain feel more confident navigating up-and-down motion—like in a deep squat.

This reduces subconscious “braking” from the nervous system and often leads to instant gains in squat depth, balance, and control.

 

 

Visual System: When the Eyes Disrupt the Squat

When we think about squatting mechanics, we often focus on the hips, ankles, or spine.

But rarely do we ask: What are the eyes doing?

The visual system is one of the brain’s most powerful sources of input.

It tells the brain where we are in space, how we’re moving, and whether we’re upright or off balance.

And during a deep squat—especially with an overhead dowel—your eyes are working hard to stabilize posture, track movement, and help your brain coordinate multiple joints at once.

If the visual system isn’t locked in, the nervous system loses confidence.

The body compensates.

That means:

  • Leaning forward

  • Dropping the arms

  • Losing balance

  • Or simply “feeling off”

All of these can be traced back to unstable visual input—and once you know what to look for, the clues are everywhere.

Why it matters:
The brain uses visual input to help organize posture and movement.

A stable gaze provides a clear map of space, which calms the nervous system and supports extension.

But when the eyes move unpredictably, or the client looks down (a visual cue for flexion), the brain perceives uncertainty—and often downgrades the movement as a safety response.


Quick Neuro Drill:
Train the Eyes, Change the Squat

  • Have your client fix their gaze on a spot slightly above eye level while squatting.

  • Don’t let their eyes move.

Why it works:
The brain follows the eyes—literally.

Looking slightly upward signals to the nervous system that spinal extension is safe and necessary.

This can improve upright posture, stabilize the torso, and reduce the urge to collapse forward.

**Bonus Neuro Drill:
Pencil Pushups for Postural Control

Pencil Pushups.

  • Hold a pencil at arm’s length, focus on the tip, and slowly bring it toward the nose while keeping it in focus for 8-10 reps. 

  • Stop if the image doubles or the eyes can’t converge.

Why it works:
Pencil pushups train ocular convergence and activate the midline cerebellum—a part of the brain responsible for coordination and postural tone.

By improving how the eyes work together, you give the brain more accurate visual input—which can directly enhance balance, spinal control, and full-body coordination during complex movements like the squat.

 

  

3. Proprioceptive System: The Body’s GPS

Your client might not feel their ankles, hips, or core well.

That fuzzy proprioception creates doubt for the brain.

So it compensates with tightness or cautious movement.

If someone:

  • Wobbles a lot
  • Shifts weight to one side
  • Overshoots or undershoots depth…that’s proprioceptive fuzz.


Why it matters:
Proprioception is how the brain senses joint position, pressure, and movement—especially at the ankles, knees, and hips during a squat.

If that input is blurry or dulled (from past injuries, wearing cushioned shoes, or underuse), the brain doesn’t get clear signals about where the body is in space.

When that happens, the nervous system defaults to safety strategies like:

  • Stiffening up

  • Leaning forward

  • Under-shooting range

  • Keeping the heels off the ground

Put simply: if the brain doesn’t know where your body is, it won’t let you move confidently. Clear proprioceptive input = smoother, more stable squats.

Quick Neruo drill: 

Try 10–15 ankle rocks or ankle circles.

These wake up joint receptors and sharpen the brain’s map of the body. 

Re-test: you’ll often see better knee tracking and heels stay down easier.

Why it works:
These movements wake up proprioceptors—tiny sensors in the ankle joint that send position and movement info to the brain.

When these receptors are more active, the brain has a clearer map of the lower body.

That means better joint control, improved knee tracking, and heels that stay grounded—because the brain no longer feels uncertain about foot position.

 

 

4. Cerebellum & Brainstem: The Movement Orchestrators

The cerebellum sequences joint timing and smoothness.

If the squat looks clunky, out of order, or like a “freeze-frame movie,” your cerebellum might not be getting the info it needs.

The brainstem, meanwhile, houses survival reflexes. 

A deep squat can trigger startle, especially if someone feels stuck or exposed at the bottom.

Why it matters:
The cerebellum is like your movement’s quality control center—it sequences joint timing, smooths coordination, and helps you stay balanced.

A squat isn’t just down and up. It’s a complex chain:
Ankles bend → knees bend → hips flex → spine stays tall.

When that sequencing is off—hips shoot back, knees dive forward, spine collapses—it often reflects a cerebellar mismatch.

If the cerebellum isn’t getting clean sensory input (from the eyes, vestibular system, or joints), it can’t fine-tune the movement.

That’s when squats get clunky, asymmetrical, or effortful—despite adequate strength and mobility.

Training the cerebellum can unlock more fluid movement patterns by restoring the brain’s ability to sync everything up.


Quick Neuro Drill:
Calm the threat response. 

Add slow tempo squats with long exhales. 

Or use cross-crawl patterns to activate cerebellar sequencing.

Why it works:
These drills calm the threat response and engage key motor control centers like the brainstem and cerebellum.

  • The slow exhale reduces sympathetic (fight-or-flight) activity and activates deep core stability via the diaphragm.

  • The cross-crawl helps the cerebellum coordinate joint sequencing and balance.

Together, they help the brain feel safe and organized—so movement becomes smoother, more stable, and less effortful.

 

 

Case Study:

Fixing a Squat in 2 Minutes

Let’s say your client scores a 1 on the deep squat.

Their heels lift, arms drop, and they lean forward.

Here’s what a session might look like:

  1. Assess: Show them their current squat on video. 
  2. Drill: Try ankle mobility (ankle rocks or skin stem on the ankles) + saccule bounce (20 seconds).
  3. Reassess: Repeat squat. Boom—heels down, torso more upright.

And just like that clients will seem amazed. 

You didn’t stretch them.
You didn’t foam roll.
You didn’t grind through another round of corrective reps.

You just gave their brain new, safer input—and the body responded.

In under a minute.

So if we’re talking about improving movement quality, symmetry, and squat mechanics…

Didn’t we just do that?

And not with weeks of mobility drills—but with seconds of the right neural stimulus.

When the brain feels safe, it allows better movement.
Simple as that.

This is the power of working with the control center, not just the muscles it governs.

  

 

Why Applied Neurology Works (And Why It Works So Fast)

Most traditional approaches work from the outside in.

They stretch a tight muscle.
They strengthen a weak one.
They roll, press, pull, and cue.

Over time, that can help.
But it’s slow—because you're trying to change the hardware.

Applied neurology flips that.

It works from the inside out—by changing the brain’s input and perception.
You’re updating the software that controls movement.

Think about it like this:

  • If the brain doesn’t trust a movement, it will tighten, restrict, or protect—no matter how many reps you do.

  • But if the brain feels safe, it often gives you instant access to more range, more stability, and better coordination.


That’s the power of applied neurology.

Instead of fighting the brain’s protective patterns, you give it a reason to let go.

Instead of grinding through dysfunction, you remove the reason for the dysfunction in the first place.

It’s not magic.
It’s how the nervous system actually works.
And when you tap into that system—the results don’t just come faster…
They stick.

 

 

Why Brain-Based Drills Work Faster Than Traditional Correctives

Let’s look at the difference between the traditional approach and a brain-based one—because how we interpret a movement issue completely changes how we solve it.

Take tight calves during a squat. 

Most coaches would prescribe stretching or foam rolling. 

But in the brain-first model, we ask a different question: why are the calves tight in the first place?

Often, it’s not about the muscle—it’s about the brain not getting clear input from the ankle joint.

So we focus on waking up ankle proprioception instead. And just like that, range improves—without ever stretching.

Same goes for core weakness. 

Rather than grinding out planks and dead bugs, we can stimulate the vestibular system—the brain’s balance center—which activates postural muscles naturally. 

Suddenly, clients feel more stable in the bottom of the squat because their balance system is online.

Instead of endlessly foam rolling the thoracic spine hoping for better posture, we can train the midline cerebellum—which controls balance and postural tone—by using a simple visual drill like pencil pushups.

When the brain gets better visual tracking and midline control, posture often self-corrects—no foam roller needed.

And rather than cueing form over and over (“chest up! core tight!”), we create safety in the nervous system—so good form emerges on its own. 

Because when the brain feels safe, it allows smoother, stronger, deeper movement.

No micromanaging required.

That’s the power of treating the brain, not just the body.

 

The bottom line? 

If the brain thinks the squat is dangerous, it will protect you from doing it well.

Show it safety, and it will reward you with mobility and control.

 

 

NEURO DRILL MENU FOR COACHES

 

System Drill Goal When to Use
Vestibular Saccule bouncing (20 sec) Increase depth, balance Client feels “off” at bottom
Visual Pencil Pushups Upright posture, stability Arms drop, lean forward
Proprioception Barefoot ankle rocks Heels stay down, knees track Client wobbles or overshoots
Breathing/Core Slow exhale into depth Stabilize spine, reduce threat Client collapses or feels unstable
Cerebellum Cross-crawl pattern (slow) Sequence movement, reduce clunkiness Disjointed squat timing

 

Always assess, drill, reassess. If you see a better squat—even 10% better—you’ve found the nervous system’s “yes.”

You can learn our Next Level Neuro Assess and Reassess process here in our Free Master Class.

 

 

The Brain Holds the Key

The deep squat is one of the most revealing movements a client can do.

But what it reveals isn’t just muscle tightness—it’s neural behavior.

When we start seeing movement as a conversation with the brain, everything changes:

  • Frustrated clients become curious again.
  • Coaches stop guessing and start testing.
  • Results come faster—and they stick.

You’re not just helping someone squat better.

You’re helping their nervous system trust itself again.

And that changes everything.

The deep squat is just the start.

 

Over the coming weeks, we’ll be unpacking the rest of the FMS—hurdle step, in-line lunge, shoulder mobility, and more—so you can see how applied neurology changes everything.

Stay tuned, and let’s keep building a brain-first toolbox that actually works.

 

 

Do You Want To Learn More?

If you want to learn how to integrate applied neurology into your assessments and sessions, grab our free 2-part Masterclass Series. We break down the exact tools, assessments, and drills that create lasting change—faster.

 

If you are interested in our Next Level Neuro Mentorship and looking to learn everything there is in Applied Neurology, NO NEUROSCIENCE DEGREE NEEDED, click here.

 

 

NEURONEWS HOMEPAGE

Contact Us For More Information Our Mentorship.