Study Spotlight: Load on the Knee Joint and Vertebral Column w/ Changes in Squatting Depth and Weight Load

By: Joel Luedke

This is another literature review that is trying to glean as much truth out of previous studies as possible and it is a good one and we think it is very important.  There is a lot of misinformation on squats and squat form and we can getting deeper into the details of squat technique in another posts.  In this one we are looking at depth and the saying 'going below parallel for the squat is bad for the knee'.  Is it really that bad for you to go below parallel or is it a thing that was said and just stuck?  Check it out below.

What They Did:

Researchers took a look at the literature in regards to knee and lumbar position when squatting.  They reviewed over 164 articles  just from between 2011 and 2103.

What They Found:

Based on the review of all the biomechanical calculations and measurements they could find via cadaver knee joints they found that the highest retropatellar compression forces and stresses can be seen at 90deg.  Researchers also found that with increase knee flexion there are several forces that help to make the squat easier on their knees.  The wrapping effect* contributes to better load distribution and enhanced force transfer with lower compressive forces on the back of the patella.  There is also increases in displacement between the surfaces of the femur and tibia.

What It All Means:

The hard part about all of this there are no realistic estimations of knee-joint forces for knee-flexion angles beyond 50 deg in the deep squat.  Going to parallel (90deg) can actually put a lot more stress on your knees and especially as they found in the literature.  This presents a problem when we are told to stop at parallel and then come back out of the squat.  We are directly putting as much force as possible on the back of our patella when we do so.

There appears to be no good evidence of degenerative changes in the tendon femoral complex and nothing found in creating more long term injury or damage to the knee.  In fact due to the increases in space, the wrapping effect and decrease in retropatellar force going deeper in your squats can actually be protective of your knees.

Bottom line; when the squat is performed properly and technique is good you are safe to work below parallel (90deg) of knee flexion, in fact it is actually safer than stoping at parallel.  Keep squatting, work on getting low and save your knees.

*Wrapping Effect: With increasing flexion the additional contact between the quadriceps tendon and the intercondylar notch as the tendofemoral support surface contributes to an enhanced load distribution and enhanced force transfers.

LINK: Analysis of the Load of the Knee Joint and Vertebral Column with Changes in Squatting Depth and Weight Load