The reason

In engineering, every man-made structure — bridges, buildings, cranes, towers — is judged by one brutal law:
The entire system is only as strong as its weakest link.

You can have steel beams rated to withstand hurricanes, but if one joint is compromised, the whole structure becomes unstable. Engineers obsess over angles, load distribution, and joint integrity because the failure of one small area can ripple through and collapse the entire thing.

Powerlifting works exactly the same way — especially the squat.

The Human Body Is a Structure… and the Knees Are Usually the Weak Joint

When a lifter squats, their body acts like a dynamic load-bearing system:

• The hips generate the power
  
• The quads and glutes extend the knees and hips
  
• The torso stabilizes
  
• The feet provide the foundation
  

But the knees?
They’re the “joint” equivalent of the weakest connection in a bridge.
If that joint collapses under load, everything else is compromised.

And nothing exposes that weak link like knee valgus — AKA “knees caving in.”

What Happens When Knees Cave In (and Why It’s a Problem)

Some valgus is normal and lifters can still hit strong numbers with minor movement. But consistent, uncontrolled caving under load is a structural failure in progress.

Here’s why:

1. Your joints are no longer stacked to transfer force

If your knees dive inward:

• The ankles collapse inward
  
• The femur internally rotates
  
• The hip loses its mechanical leverage
  
• The glutes (your powerhouse) shut off
  
• The quads can’t extend efficiently
  
• The lower back rounds followed by the mid and upper.
  

It’s a total structural failure.

2. The force doesn’t move through the skeleton — it gets absorbed by soft tissue

When valgus occurs, the knee stops being a hinge and starts being a stress dispersal zone.
This stress loads the:

• MCL
  
• Medial meniscus
  
• Patellar tendon
  
• Hip adductors
  
• Ankle joint
  
• Low back
  

Imagine a crane arm bending sideways instead of up and down — it’s not built for that direction of force.

3. You lose both strength and stability

Knee cave is not just a power leak.
It’s a chain reaction:

• The foot collapses
  
• The ankle rolls inward
  
• The femur rotates
  
• The hip shifts
  
• The torso compensates
  
• The bar path becomes inefficient
  

One link breaks, the whole chain gets weaker.

4. It leads to injury — eventually.

You can get away with knee cave… until you can’t.

“You wouldn’t push a car with your knees caved in, right?”

If someone tried to push a stalled car with their knees smashed together like a baby giraffe that just learned to walk, you’d assume they were joking — or needed medical attention.

So why would you load 300, 400, 500+ pounds on your back and push upward with the exact same faulty position?

Why Do Knees Cave In? (The Real Causes)

It’s rarely “just your knees.” Knee valgus is typically the result of:

• Weak or timing-delayed glutes
  
• Poor foot rooting
  
• Lack of external rotation torque
  
• Weak adductors (yes, weak adductors can cause collapse too)
  
• Unstable ankles
  
• Technique breakdown under fatigue
  
• Load exceeding structural integrity
  

It’s not about the cue “knees out” — it’s about stable alignment and consistent torque creation.

How to Fix It

This is where coaching matters. A strong squat requires a system that is aligned, stable, and efficient.

1. Fix the feet first

The foot is the “foundation”
Wide tripod pressure:

• Big toe
  
• Pinky toe
  
• Heel

Try barefoot squatting with lighter weights just to get a feel for the pressure you need to feel on each section. Then try to replicate that in shoes. I recommend wide toebox shoes.

2. Strengthen hip external rotation

• Banded walks
  
• Clamshell variations
  
• Glute med/min work
  

3. Strengthen the adductors

These are critical for stabilizing the knee from the inside:

• Copenhagen planks
  
• Adductor bridges
  
• Long-stride lunges
  

4. Practice proper bar path and squat patterning

• Tempo squats
  
• Paused squats
  
• Controlled low-RPE technique work
  
• Pin squats just above parallel.
  

5. Load progression that respects biomechanics

This is where you will have to take 2 steps backwards to take 10 steps forward. Start light and work up in weight. When you see your technique starting to break down, this is where you stop. I don’t care how low of a weight it is. This shows you how much or how little work you need to do and where. Check your damn ego at the door.

You don’t fix collapsing joints by repeatedly loading them until they collapse harder.

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Final Thoughts

The squat is a brutally honest lift. It doesn’t care how strong you think you are — it exposes every weak link in your chain. And knee cave is one of the biggest, most common, and most costly weak links in powerlifting.

What’s interesting is that even some of the top lifters in the world still show major knee valgus under heavy loads. And honestly? I’m not sure why they don’t fix it. Maybe they don’t think it’s a problem because they’re already at the top of the sport. Maybe their coaches don’t know how to address it. Or maybe the lifters themselves never learned the right way to build stability in the first place and relied solely on their genetic potential put together with a solid program.

But just because someone is strong despite a flaw doesn’t mean the flaw isn’t there — it just means they’re succeeding around it.
For the rest of us, and for anyone who wants to lift longer, safer, and stronger: fixing your weak links is the smartest investment you can make.

Strong technique isn’t optional. It’s the foundation everything else rests on.

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Ready to fix your squat and eliminate the weak links holding you back? Click here to work with me and get a customized plan that builds strength safely and efficiently.