Why your knees cave in when you squat
Your knees travel inward when something above or below them is short, and something else has stopped holding its position. Here is what the pattern means, what it is associated with, and what changes it.
I am Brad Glaser and I have watched this in an Irvine studio since 2008. The overhead squat screen names it, the muscle lists explain it, and the cues below are what I say to change it.
What it looks like from the front
Stand as you normally would and start down. Sit back further, aim for thighs at least parallel to the floor, then watch your kneecaps. If they drift toward each other, that is the pattern.
Film it from the front at knee height, because a camera beside you cannot see a knee travel sideways. One leg at a time exposes it sooner than two, so try a single leg squat and compare sides.
The muscles the screen calls short
The screen calls these probably overactive, which means short and tight. On that list are your TFL, your adductor complex, your vastus lateralis, your lateral gastrocnemius and the short head of your biceps femoris.
Short muscles pull. The adductor complex runs along your inner thigh and pulls the knee toward the midline every time you load it. The TFL and vastus lateralis pull from the outside.
The muscles that went quiet
Probably underactive, long and weak, the screen says: your VMO, your medial hamstring, your medial gastrocnemius and your gluteus medius and maximus. The VMO is the inner head of the quad, just above the kneecap.
The gluteus medius is the one that keeps your thigh bone from rotating in. When it stops doing that, the knee follows the pull of everything short. Underactive does not mean damaged. It means the muscle is not holding.
Why the knee is not the culprit
Your knee is a hinge. It bends and straightens, and it has very little say in which direction it ends up pointing. Your hip and your ankle make that decision for it.
A foot that flattens or turns out usually means tight calves and a weak anterior tibialis. A flattening foot can carry the knee inward. Heel rises in the screen name the same pair, so we check the ankle too.
What this pattern is associated with
The findings table in my app lists what this pattern is associated with: anterior, medial and lateral knee pain, and IT band tendonitis. Associated with the pattern, not a statement about you.
That is also why a cave that has been there for years is worth looking at rather than guessing about. If you have a condition, get cleared by your own doctor first. Individual results vary.
Your trainer
I am Brad Glaser. Five certifications: NASM CPT and Master Trainer, NASM-CES, NASM-PES, NCSF and PFIT, plus a current CPR card. Training clients since 2005, in this Irvine studio since 2008.
NASM-CES is the corrective exercise credential, and knees that cave in are exactly what it is for. I train on the NASM OPT model: start from the basics and progressively advance.
What I say when I see it
These are the words I say. Drive your knees out over your toes as you descend. Push your knees out in the direction your toes are pointed, which is not always straight ahead.
Two more, for the setup rather than the rep. Widen your stance, feet well outside your hips, toes turned out. Walk your feet out slightly so your knees stay above your ankles.
Strengthen what is weak, stretch what is tight
In every case the fix follows the same pattern: strengthen what is weak, stretch and massage what is tight. Here that means length for the adductor complex and the TFL, then strength for the gluteus medius and the VMO.
So the cue buys you the rep in front of you. The gluteus medius work, the VMO work and the calf length are what earn the next squat without the cue. Individual results vary.
When the knee tracks outward instead
Some knees do the opposite under load and travel outward. That version usually means your IT band is tight, your glutes may be tight as well, and your abductors are often weak or loose.
This is why a cue you read somewhere can be exactly wrong. Push your knees out when they already track out and you are driving the pattern further, not correcting it.
What the free hour actually answers
The first hour is free and it starts with questions, not weights. Add any injury or surgery, past or present. Then your flagged areas. On a caving knee those often sit at the hip or the ankle.
Then we watch. The posture and movement check is where a knee that caves shows itself. You leave with the finding and a plan, no credit card and no obligation.
Questions
Can I fix this on my own?
Some of it. Try the cues and see what changes. Individual results vary. Knowing which muscles are short on you, and in what order to work them, is what a movement screen is for.
Should I stop squatting for now?
Usually not. We change the stance, the depth and the load so the pattern stops being rehearsed, then build the glutes and the VMO underneath it. Individual results vary.
Will stretching my inner thighs help?
It can, if the adductor complex is short on you. Stretching the medial hamstring or the gluteus medius, which are the weak side of this pattern, would push it further the wrong way.
Does it matter if only one knee caves?
It matters a lot. A side difference points at the hip that is doing less. On that side you will hear drive your knee straight up in line with your hip, not caving inward.
Is the first session really free?
Yes. One hour, no obligation, and you do not need a credit card. Call (949) 574-4755 or use the form and Brad calls you back within 1 business day.
Book your free session
The studio is at 17165 Von Karman Ave, Suite 103, Irvine, CA 92614. Hours are Monday to Friday, 6 AM to 8 PM, closed weekends.
Call (949) 574-4755 or use the free session form with your name, email and phone. Brad will call you within 1 business day to book a time. Plans from $197 a month.
