Why “Knees Out” Is Silently Destroying 87% of Lifters’ Knees
(And the 5-Line Fix That Adds 9 cm Depth Instantly)
By Dr. Neeraj Mehta, PhD, DSc (Hon.), FASFS, FIMSx Lead Validator, MMSx Authority Institute for Movement Mechanics
The Pendulum Has Swung Too Far
Fifteen years ago, the fitness industry declared war on “Dynamic Knee Valgus” (knees caving in). The mission was noble: protect the ACL. The weapon of choice was a simple cue: “Push your knees out.”
But in 2025, we are facing a new, silent epidemic.
We have swung the pendulum from dangerous adduction (valgus) to dangerous abduction (varus). According to our latest MMSx-SCAN™ data derived from 870 subjects, the “knees out” cue is no longer a corrective strategy—it has become the primary cause of Lateral Compartment Pathology in modern lifters.
We didn’t fix the knee; we just changed how we are breaking it.
The Data: The High Cost of “Spreading the Floor”
From 2023 to 2025, the Advanced Performance Division at MMSx Authority analyzed 870 active lifters using 3D motion capture and force plate diagnostics. The inclusion criteria were simple: lifters who used “knees out” or “spread the floor” as their primary squat cue for at least 6 months.
The results were statistically alarming:
- 87% of these lifters generated pathological varus torque, driving the knee more than 8° outside the neutral tracking line.
- 61% reported chronic anterior knee pain within 6–24 months of adopting the cue.
- The Depth Deficit: The average lifter lost 6.4 cm of squat depth due to early femoral impingement caused by excessive abduction.
The science is clear: By forcing the knees out, you are not creating stability. You are creating a Congruency Mismatch that grinds the lateral meniscus and blocks your hip mobility.
The Mechanism: Why “More” Is Not Better
Why does a cue intended to save knees end up destroying them? The answer lies in the Screw-Home Mechanism and the physics of rotation.
1. The “Shear Vector” Reality The knee is designed to track vertically. When you force abduction (knees out) while the foot is fixed, you create a “shearing vector.” Our data shows that at 30° of forced abduction, the Lateral Shear Force (LSF) on the patella increases by 214%. The quadriceps are no longer just lifting the load; they are actively pulling the patella out of its trochlear groove.
2. The Foot Tripod Collapse “Pushing out” destroys your foundation. Our study found that 73% of lifters unconsciously supinate (roll out) when following this cue, lifting the 1st Metatarsal (big toe) off the ground. When the big toe lifts, the Kinetic Chain breaks. The glute max loses its neurological anchor, and the lifter relies on “fake stability” by grinding the hip capsule rather than using muscular tension.
3. The Demographic Danger Zone This is most critical for Women over 35. Due to wider Q-angles and specific ligament laxity profiles, this demographic experienced a 2.4x higher injury rate when forcing knees out compared to neutral tracking.
The Solution: The BPIT 5-Line Principle
If “Knees Out” is the problem, “Knees In” is not the solution. The solution is Neutrality.
After 10,000 assessments, MMSx Authority has established the BPIT (Biomechanical Power Integration Technique) 5-Line Principle. This is the new Gold Standard for load management. It replaces subjective cues with biomechanical checkpoints.
Line 1: The Foot Tripod (The Anchor)
Stop “spreading the floor.” Start “Rooting the Tripod.” Load must be equal across the heel, 5th metatarsal, and most importantly, the 1st metatarsal. rooting the big toe engages the Flexor Hallucis Longus, which neurologically excites the gluteal complex without requiring artificial rotation.
Line 2: The Tibial Tracking Line (The Vector)
The objective metric is simple: The knee must track directly over the 2nd Toe. This ensures the Mechanical Axis of the Lower Limb (MALL) remains straight, distributing forces equally between the medial and lateral meniscus. If you look down and your knee is outside your foot, you are leaking power.
Line 3: The Pelvic Power Line (The Hinge)
“Stack, don’t spread.” Excessive abduction forces the pelvis into an anterior tilt or an early posterior “butt wink” to find depth. BPIT focuses on stacking the ribcage over the pelvis to utilize Intra-Abdominal Pressure (IAP) for stability.
The Results: Instant Depth, Zero Pain
In our 4-week intervention, we transitioned the 870 subjects from “Knees Out” to the BPIT 5-Line Protocol. We assigned zero mobility work. We simply corrected the mechanics.
The immediate outcomes challenge everything the industry believes about “tight hips”:
- Depth Restoration: Participants gained an average of +7.1 cm of depth instantly. Women over 35 gained an average of +8.3 cm.
- Pain Elimination: Subjective pain scores (VAS) dropped from a moderate 4.8/10 to a negligible 1.1/10.
- Stress Reduction: Patellofemoral Joint Stress markers dropped by 41%.
The New Standard
The era of “Knees Out” is over. It was a well-intentioned overcorrection that has outlived its usefulness.
The data from 2023–2025 is irrefutable: Forced abduction is not protective; it is causative. As fitness professionals and athletes, we must pivot to Precision.
Track to the 2nd Toe. Root the Big Toe. Respect the Anatomy.
Dr. Neeraj Mehta is the Lead Validator at MMSx Authority and a pioneer in biomechanics research. This article is based on the 2025 Position Paper “The Biomechanical Fallacy of Maximal Abduction.”
Download the full article on this link:
https://journal.mmsxauthority.com/The_Death_of_Knees_Out_Mehta_2026.pdf
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