Truth or Myth: Squats Are Bad for Your Knees

The claim

Squatting wears out your knees. Deep squatting especially. Everyone has an uncle who says it.

This one is interesting because the scary half is actually true. The loads are genuinely huge, and measured.

What does not follow is the conclusion.

The loads really are enormous

Twenty-nine top-ranked Austrian powerlifters, 16 men and 13 women, squatted at 70 to 90 percent of their one-rep max while 3D motion capture and force plates fed a musculoskeletal model estimating joint contact forces.

At 90 percent of max, average peak joint contact forces came out at 15.5 times bodyweight at the hip, 23.2 at the tibiofemoral joint, which is the main knee joint, 26.7 at the patellofemoral joint, which is behind your kneecap, and 11.5 at the ankle.

Twenty-six times your bodyweight through the back of your kneecap.

There is a second detail that matters more than the headline number. The hip and ankle peaked in the deepest position, but the knee joints held consistently high loads across a broad portion of the whole squat cycle. The knee is not spiked at the bottom, it is loaded throughout.

So anyone telling you squats put big forces through your knees is correct. That part is not the myth.

Load is not damage

Here is where the reasoning breaks.

A state-of-the-art review examined why quadriceps strengthening, despite being guideline-endorsed and biologically plausible, delivers only modest and inconsistent benefits at population level in knee osteoarthritis.

Read what is baked into that question. Strengthening is guideline-endorsed for arthritic knees. The review states it remains one of the best-supported non-pharmacological interventions for knee osteoarthritis, providing average improvements in pain and function.

The thing supposedly destroying knees is the thing prescribed for damaged knees.

The review's actual concern is not that strengthening harms people. It is that the benefits get diluted in real-world care: patients differ, symptoms fluctuate, people stop doing the exercises once supervision ends, doses are too low, and follow-up support and reimbursement are limited. Its conclusion is that strengthening should be individually adapted within a high-quality framework rather than prescribed one-size-fits-all.

Under-dosing appears in that list. Not over-dosing.

Why bone and cartilage are not furniture

The intuition behind the myth is that a joint is like a hinge on a door, and using it wears it down.

That model is wrong for living tissue. Living tissue responds to load by adapting. That is the entire basis of training, and it is why strengthening is prescribed for arthritic knees rather than rest.

Where the analogy does hold: adaptation takes time, and it can be outpaced. That is the argument for adding weight gradually. It is not an argument for avoiding load.

I should be clear that neither study above measured whether squatting causes knee osteoarthritis. Nobody here ran that trial. What the evidence supports is that high knee loads occur during squatting, and that loaded strengthening is a first-line treatment for the condition people fear squatting will cause.

Stance width does change what your knee feels

Eight healthy female university students performed partial squats at two stance widths, shoulder width and 1.5 times shoulder width, at three foot angles, straight ahead, 20 degrees in and 20 degrees out. Twelve-camera motion capture and force platforms, analysed with correlation and regression.

Stance width significantly affected knee adduction, abduction and external rotation moments. A wider stance reduced knee adduction moments, which the authors linked to relieving stress on the medial compartment, the inner side of the knee, and that is the compartment most often affected in knee osteoarthritis.

Foot placement angle mainly influenced knee extension and rotation moments, with some angles increasing knee extension demand.

So if the inside of your knee is the part that complains, a wider stance is a cheap thing to try.

Eight participants, all female university students, doing partial squats. That is a very small study and the smallest sample in this piece. Treat it as a direction to experiment in, not a prescription.

The verdict

Myth, with the loads left intact.

Squatting genuinely produces very large forces at the knee, up to 26.7 times bodyweight behind the kneecap in elite lifters at 90 percent of max, sustained across much of the movement rather than only at the bottom.

What does not hold is the leap from large force to inevitable damage. Loaded strengthening is one of the best-supported treatments for the arthritic knee, and the current problem identified in the literature is that people do too little of it, not too much.

The honest limit: no study here tracked squatters over years to see who developed knee problems. So this is a myth that fails on its reasoning rather than one that has been directly disproven by outcome data.

What to actually do

Add weight gradually. Tissue adapts to load over time and that is the mechanism you are relying on.

Squat to a depth you can control. The powerlifter data showed the knee loaded throughout the movement, so depth is not where the knee suddenly becomes vulnerable.

If the inside of your knee is the sore part, widen your stance and see what changes.

If you already have diagnosed knee osteoarthritis, strengthening is in the guidelines, but the review is explicit that it should be individually adapted. That is a conversation with a clinician who can see your knee, not something to take from an article.

And if something hurts sharply during a lift rather than being merely hard, that is a signal to stop and get it looked at.