Are Deep Squats Bad for Your Knees? 'Stop at Parallel' Myth vs Research
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Written by: Hirotsugu YoshimuraReviewed by: Tomonobu Someda
'Squatting below 90 degrees wrecks your knees' and 'half squats are plenty — going deeper is dangerous' are old beliefs that persist today. Are deep, full squats really bad for your knees, or is stopping shallow leaving gains on the table? We examine the research from two sides: load on the knee, and effects on hypertrophy and strength.
Let the data settle it.
Do deep, full squats damage the knees?
What's said
古くからの通説、一部の指導現場
The deeper the knee bends, the more stress on the joint. Full squats damage your cartilage and ligaments, so you should stop before your thighs reach parallel.
What research says
- For healthy knees, there's little basis for the idea that deep squats are harmful.
- A review by Hartmann et al.
- (2013) examining 164 studies reports that patellofemoral (kneecap) compressive stress actually peaks around 90 degrees, and that squatting deeper distributes load via a 'wrapping effect.' The concern that deep squats raise the risk of cartilage softening or osteoarthritis was deemed 'unfounded.' If anything, handling supramaximal loads in half or quarter squats may stress the knees and spine more over time.
- The premise, however, is a healthy knee and proper form.
'Full squats are bad for your knees' isn't supported by research for a healthy knee with proper form — squatting deep doesn't inherently wreck your knees. It's a different story for people with prior injuries, or those loading heavy without adequate mobility or form; if you have pain, consult a professional. This article is educational and for reference.
Are half squats good enough for results?
What's said
可動域を抑えたい層の主張
Half squats train the legs plenty. There's no point going deep, and no need to take on risk just to increase range of motion.
What research says
- Going deep tends to be advantageous for hypertrophy and strength.
- In a 12-week RCT by Bloomquist et al.
- (2013; n=17), the deep-squat group (0–120 degrees) showed greater adaptations than the shallow group (0–60 degrees) in front-thigh cross-sectional area (+4–7%), isometric knee-extension strength, and squat jump (+15±3%) — with no adverse effect on the knee tendon (no difference in tendon area).
- A larger range of motion is far from wasted; it benefits leg development.
- That said, the study was small (17 healthy young men), so read it with some caution.
Half squats do work, but if you can squat deep safely, full squats likely give you more for leg hypertrophy and strength. Those with good mobility have reason to squat deep within a comfortable range. Still, the evidence rests mainly on small RCTs and assumes good form and individual variation.
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Related research
Sources
- Hartmann H, Wirth K, Klusemann M (2013) Sports Med — Analysis of the load on the knee joint and vertebral column with changes in squatting depth and weight load
- Bloomquist K, Langberg H, Karlsen S, Madsgaard S, Boesen M, Raastad T (2013) Eur J Appl Physiol — Effect of range of motion in heavy load squatting on muscle and tendon adaptations
Published:
Written by
Hirotsugu YoshimuraFounder of BODYDATA / CEO of INVOLVE
I don't pick things because they "seem good." I check the data first, then test it with my own body.
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Reviewed by: Tomonobu Someda
Content reviewed from the perspective of coaching practice and supplement-industry experience
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