IS THE DEEP SQUAT BAD FOR YOU KNEES?
From the time that we’re very little, we have the natural ability to perform a deep squat. It’s only as we age, and start moving less and sitting more, that we begin to lose that ability. Our muscles tighten and our joints stiffen as we spend less time working through full ranges of motion. Everyone should have the capability to perform a bodyweight squat to full depth, and contrary to popular belief, those who do not have the ability to perform a deep squat are the ones who are at greater risk for injury. Dr Aaron Horschig wrote a great article on the deep squat which can be found at squatuniversity.com, here is a bit of what he says:
The ligaments inside our knees are actually placed under very little stress at the bottom of a deep squat. Stress to the ACL (anterior cruciate ligament) during a squat is actually highest during the first 4 inches of the squat descent, and as depth increases, the forces placed on the ACL ligament significantly decrease. The PCL (posterior cruciate ligament) sustains max forces just above parallel in the squat, and just like the ACL, the PCL is never placed under excessive stress during the squat. In fact, the deeper you squat, the safer it is on the ligaments in your knee as shear forces dramatically decrease due to an increase in compression. There is very little evidence that compression forces placed on the knee during squats cause any wear and tear on the joint. As well, the hamstrings and quadriceps in our legs work together to stabilize and limit excessive movement deep inside the knee.
Science has actually shown that squatting deep may actually have a protective effect on our knees by increasing its stability, and that athletes who perform the deep squat have more stable knee joints and less laxity in the ligaments of the knee.
All that being said, if you’re experiencing pain during the squat, or if you are having trouble performing a deep squat with good technique, the risk for injury increases. Always make sure you can move through a full range of motion pain free before applying load. - Dr Aaron Horschig, Squat University