Squatting is a foundational human movement, along with pushing, pulling, rotation and hinging. You may hear warnings that squatting below parallel is dangerous for your knees, but that's a myth. With proper biomechanics, you should be able to perform a deep squat without knee pain. However, it might not be possible if you have weak hips, lack of joint mobility or poor form.
Weak glute muscles, poor ankle mobility, improper form or an unrelated condition could be the reason you're experiencing knee pain from squats.
The Truth About Squats
No matter what you've heard, full squats aren't bad for your knees. It's a resting position for people in Eastern countries, but Westerners typically lack the mobility to comfortably assume the position — which is likely, partially responsible for the false belief that you can get a knee injury from squats below parallel.
The concern that causes many health professionals to warn against squatting below parallel is that it potentially increases the risk of knee laxity, or weakness of the ligaments of the knee joint, and puts excessive pressure on the knee.
However, according to a study published in 2014 in the Journal of Strength and Conditioning Research, that's untrue. In fact, previous research has shown that deeper squats only result in increased activation of the gluteus muscles and that experienced weightlifters actually have less knee laxity than sedentary people.
In addition, according to a 2015 scientific review by Tony Ciccone et al. of the Center for Sport Performance at California State University, stress on the knee actually decreases when the angle of the knee passes 90 degrees.
So, just to clarify, it's most likely not a knee injury from squats that is causing your pain.
You should not continue to do full squats with pain. See a physical therapist or work with a trainer to solve the problem that's causing your pain before resuming full squats.
Your Hips Are Weak
Physical therapist Jonathan Gayed says that in his experience, the most common reason for knee pain during deep squats is weak hip muscles — specifically the gluteal muscles. The glutes help stabilize the knees; if the glutes are weak, the knees won't track straight, typically caving in with the force. When this happens repetitively and under load, it can cause pain and tissue damage.
Hip thrusters. Sit on the floor in front of a weight bench positioned lengthwise with your knees bent and your feet flat on the floor. Place a barbell or a dumbbell across your hips (use a pad for cushioning). Press your shoulders into the bench and raise your hips up to full extension. Keep your knees at a 90-degree angle. Lower down; then repeat.
Outer thigh extensions. Use the abductor machine at the gym or use resistance bands. Sit on an exercise step and place a closed-loop resistance band around your knees. Open your knees against the resistance; then return to starting.
You Have Limited Ankle Mobility
You'll know if you don't have effective ankle mobility because you won't be able to get as deep in a squat as you'd like to. This can cause overcompensation that affects your form and increases the forces on your knees.
Knee-to-wall ankle mobilization. Stand facing a wall with your toes about 4 inches from the wall. Place your palms on the wall and step one foot back as if you're going to do a calf stretch. Bend into your front knee as you shift the weight forward, attempting to touch the wall with your knee. Your back heel can lift but your front heel should stay on the floor. Do 10 repetitions; then switch sides.
Banded ankle mobility. Anchor a resistance band and loop it around your ankle. Walk away from the anchor point until the band is taught; then kneel on the knee of the unbanded leg. Press forward, allowing the knee of the banded leg to extend beyond the banded ankle until you feel tension in your ankle. Hold three seconds; then release. Do 10 reps on each side.
You Are Using Improper Form
You can really mess up your body if you use incorrect form during a deep squat, especially if you are using a considerable load. The wrong form can put too much pressure on your knee joints, which can cause an acute knee injury from squats or can lead to an overuse injury over time. The key is to go back to basics. Get rid of the weight and practice proper technique, the finer points of which are:
- Use an athletic stance with your toes pointed slightly out.
- Keep your weight in your midfoot.
- Shift your hips back slightly as you lower down.
- Keep the knees behind the toes.
- Don't let your knees bow inward.
- Maintain a neutral spine and an upward posture with the chest out, shoulders back and the gaze forward.
It's a great idea to consult a certified personal trainer or physical therapist who can observe your form and provide feedback about anything that is contributing to your knee pain. Only when you are able to complete 20 unweighted squats with correct form should you begin to add weight.
Another effective way to practice proper squatting form and prevent sore knees after squats is to perform box squats. This trains proper squatting technique by reinforcing the hip hinge and the motion of pushing the hips back. They're simple to do:
- Just place a plyo box or weight bench behind you as you are squatting.
- Reach your hips back and sit down on the bench; then stand up again.
- Maintain all other points of your proper squatting form as outlined above.
You Have an Unrelated Knee Condition
It's possible that your knee pain isn't related to squatting but is exacerbated by the movement, causing sharp knee pain when squatting. Common conditions that can cause pain in one or both knees include:
- Patellar tendinitis, which is an overuse injury that causes irritation and inflammation of the tendons of the knee.
- Osteoarthritis, which is a degenerative arthritis that occurs when cartilage in the knee decreases with wear-and-tear and age.
- Knee bursitis, which is inflammation in the small sacs of fluid — called bursae — that cushion your knee joint.
If you have tried strengthening your hips, improving your ankle mobility and working on your form and you still have knee pain, make an appointment with your doctor.
- StrongFirst: The Seven Basic Human Movements
- Journal of Strength and Conditioning Research: Knee Joint Kinetics in Relation to Commonly Prescribed Squat Loads and Depths
- Center for Sport Performance: Deep Squats and Knee Health: A Scientific Review
- RISE: Top 3 Reasons Why Your Knee Hurts When You Squat and Their Fixes
- Lee Hayward: Squat Technique Tip – Strengthen Weak Hips
- Dr. John Rusin: 10 Exercises to Instantly Improve Ankle Mobility
- Muscle for Life: Squatting and Your Knees and Back: Injury Risk or Safe?
- Mayo Clinic: Knee Pain