Case Study Breakdown: Single Leg RDL Instability

She Could Clean 200 lbs, but couldn’t balance on her left leg.

What Her Brain Was Hiding?

Case Study: From National Rugby Star to Neurological Rebuild

How Applied Neurology Restored Her Single-Leg Strength

“I can power clean 200 pounds. But I can’t hold my balance on my left leg. What the hell is that?”

Meet a 29-year-old powerhouse female rugby player and former starter for the U.S. Women’s National Rugby Team.

She’s played on the world stage.
She’s trained with the best.
She’s no stranger to pain, high-performance rehab, or Olympic-level coaching.

And yet, a single-leg RDL on her left side reduced her to shaky footing, hip rotation, and self-doubt.

I know what you are all thinking: Her glute medius on her left side isn't firing. (lol!)

That is the first thing I would have said, a few years prior to applied neurology. 

Current complaints:

• Hamstring tightness
• Poor balance on left
• Eye fatigue post-training
• Mild anxiety under max loads
• Difficulty tracking barbell under dynamic lift
• Power output severely hampered in power lifts.
• Hipe Drive in tackling and running felt sluggish (athlete and coach both concur) 

This is the story of how we stopped chasing “strength” and started working with her brain.

Athletic Background: Built Like a Tank — But Something Was Off

Our athlete came in with a pedigree few can rival:

• 4x All-American
• Starting fullback for the U.S. National Rugby Team
• Olympic trials qualifier in shot put during college
• Known for her punishing tackle and freaky hip drive
• Cleaned 205, trap-bar deadlifted 375 for reps, benched 185

But ever since her second knee reconstruction at 27, something wasn’t right.

(I know, only after the second.  Could the first be attributed to the second?) 

“I can hinge on my right leg all day. But my left side? I feel like a baby giraffe.”

She’d been through:

• PT and post-op rehab
• DNS (Dynamic Neuromuscular Stabilization) training
• Single-leg kettlebell progressions
• Functional Movement Screens (FMS) that flagged single-leg instability in Step Over and In Line Lunge. 
• Balance pad work, mobility flows, glute med circuits

But her left-side RDL never caught up. 

Biomechancial Recommendation:  A Weak Link in the Chain

The Biomechanical Breakdown:

Her rehab specialists broke down:

• Poor left foot stability
• Glute medius lagging
• Hamstring guarding
• Core control imbalance

They prescribed:

• Single-leg hip thrusts
• Foot arch engagement drills
• Banded lateral walks
• Bulgarian split squat progressions
• Step Up progressions and core strength
• Maybe even barefoot balance board work or BFR-assisted hinge regressions

And these were all good and done with the right progression and professionalism.

These helped… but only so far.

Why?

Because none of these addressed what her brain was protecting.

What We Saw: A Threatened Map in the Brain

We started with a different lens.

Not:
“What’s weak?” 

But:
“What’s noisy, mismapped, or unintegrated in the nervous system?” 

And her health history lit up like a GPS tracker for unresolved neural threat:

History Markers:

•  Concussion at 22 during a high-speed tackle; brief blackout
•  Right shoulder dislocation at 24 — led to compensation patterns and visual mismatch
•  Whiplash from a car accident at 26 (minor, but unaddressed)
•  Left ACL tear + meniscus repair at 27 
• Chronic TMJ issues — wore a night guard
• Reported left eye “blurry focus” in deep hip hinge positions

That’s not just a medical chart — that’s a brain map full of threat tags.

Tell me, how would the above biomechanical breakdown have helped her solve these neural threat tags? 

The Tipping Point: Visual-Vestibular-Proprioceptive Breakdown

In positional testing, here’s what we found:

• Standing single-leg stance on the left: stable
• Add head turn: unstable
• Add eye convergence: full collapse
• Perform RDL with eyes open: shaky
• RDL with gaze fixed on a point: improved
• RDL with tongue on roof of mouth + right toe pull: stable

Every failed input painted a picture:

The brain was struggling to integrate visual and vestibular information in a complex pattern involving rotation, flexion, and load shift ( i.e., a single-leg hinge.)

Not a strength issue.
A sensory conflict.

The Applied Neurology Reset Protocol

Step 1: Calm the Threat — Reset the Sensory System

We focused on inputs, not outputs:

•  Tongue posture drills (improved foot-to-core sequencing)
•  Visual fixation and eye circle training (retrained oculomotor control)
•  Jaw glides and vagus stimulation (regulated cranial nerve input and decreased global threat)
•  Vestibular tilts and gaze holds in half-kneeling (strengthened inner ear balance integration)

Step 2: Layer the Inputs in the Pattern

We trained her single-leg hinge using:

• Fixed gaze RDLs with light load
• Eye convergence into hinge
• Unilateral hinge with visual load + foot tension 
• Post-reset reassessments after every set. 

The result?
Instant improvement in range, balance, and confidence.
First time in 2 years, she felt “trust” on her left side.

**Could there be other choices based on the health history and injuries?  

Yes. 

We chose what we did based on the immediate feedback from the assessment/reassessment process, and the athlete was also NEW to neuro drills. 

Why This Worked: Systems, Not Symptoms

If we had kept chasing “the weak glute med,” we might still be at square one.

But the brain isn’t isolating joints.

It’s responding to:

• History
• Safety
• Input accuracy
• Internal vs. external orientation
• Integration across hemispheres

She didn’t need another monster walk.

She needed her eyes, ears, jaw, and feet to speak the same language. 

Final Results

Before: 

• Hamstring tightness
• Poor balance on left
• Eye fatigue post-training
• Mild anxiety under max loads
• Difficulty tracking barbell under dynamic lift

After 3 weeks of neural resets: 

• Single-leg RDLs matched on both sides
• Improved eye tracking and clarity
• Reduction in headaches and jaw tension
• Confidence under rotational load
• Increased bar speed off the floor in conventional pulls 

Key Takeaways for Coaches and Therapists

• Just because an athlete is strong doesn't mean they're neurologically clear 
• Indirect resets can out-perform direct interventions when the issue is driven by sensory mismatch 
• Athletic history is a neurological map, and every injury can create unseen threat tags
• Visual and vestibular systems must be assessed in the context of the pattern, not just in neutral
• Sometimes the biggest gains come from the least obvious inputs 

Our athlete and her training staff had done everything right.  Perfect execution through a BIOMECHANCIAL LENS.

She lifted. She braced. She trained. She tried every progression in the book.

But no one ever asked her brain what it needed.

Until now.

If you have any questions, please send them to [email protected]