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Limited evidenceMyth check

Deep squats (below parallel) are bad for your knees

For healthy knees there is no good evidence that squatting deep causes injury, and deep squats build more lower-body muscle than shallow ones. The real risks come from loads you cannot control and poor technique, not from depth itself.

What the science says

  • Deep squats damage healthy knees Limited evidence

    Hartmann's 2013 review of over 164 articles concluded that concerns about cartilage, ligament and osteoarthritis damage from deep squats are unfounded: retropatellar compressive stress peaks around 90° and is spread over a larger contact area at deeper flexion. It warned that half and quarter squats with much heavier loads may be the greater long-term concern.

  • Squats do not compromise healthy knee stability Moderate evidence

    Escamilla's 2001 biomechanics review found the parallel squat was not injurious to healthy knees and does not compromise knee stability. It did suggest parallel over very deep squats as a cautious choice, because forces rise near maximal flexion, though without injury data showing harm.

  • Deeper squats build more muscle Moderate evidence

    Bloomquist's 2013 trial found deep squats (0-120° knee flexion) increased front-thigh cross-sectional area more than shallow squats (0-60°) over 12 weeks. Kubo's 2019 trial found full squats grew the adductors and gluteus maximus more than half squats, with similar quadriceps growth.

What to do instead

Squat through the deepest range you can control with good technique and a load you can handle, and progress gradually.

DepthAs deep as you can control with a neutral spine and stable feet; at least parallel if comfortable
LoadUse weights you can lift through the full range; avoid heavy partial squats as a substitute
ProgressionAdd load or reps gradually, week to week
TempoControlled lowering; no bouncing out of the bottom under heavy loads
LearningGet technique coaching when starting out

Who should be careful

This applies to healthy adults. If you have knee pain, a past knee injury, surgery or arthritis, see a physiotherapist or sports medicine doctor before choosing squat depth and load; this page is not a rehabilitation guide.

Frequently asked questions

Are deep squats safe for my knees?

For healthy knees, a 2013 review found no evidence that deep squats increase injury risk, and a 2001 review found squats do not compromise knee stability.

Are deep squats better for muscle?

Trials found deep squats increased front-thigh size more than shallow squats, and full squats grew the glutes and adductors more than half squats.

What if my knees hurt when I squat?

See a physiotherapist or sports medicine doctor. The evidence here is for healthy knees and is not a rehabilitation plan.

Scientific references

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