16 May Is Knee Valgus Always Bad in Weight Lifting?
If you aren’t willing to read this entire article then please don’t waste my time commenting. Knee valgus is a very hot topic right now and I’m expressing my views on it. I was not sure I’d ever publish the following article but my recent interview with Travis Mash of Mast Elite Performance on his Barbell Life Podcast convinced me that I should. The section of this interview that discussed this topic can be listened to here: Free webinar sharing the simple squat assessment process I use to make athletes move better!
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Let’s be clear about something from the start….dynamic knee valgus has repeatedly been shown in the literature to be a mechanism of a variety of injuries. My purpose here is not to debate that. Instead, I am expressing my OPINION on valgus and why it might not be as bad as we all think…IN CERTAIN SITUATIONS.
Second, I believe knee valgus should be avoided in the vast majority of people while lifting and as close to never as possible during other dynamic activities (juming, running, cutting).
Again, this is my opinion and I reserve the right to change my opinion on this at any moment.
Defining Knee Valgus
The term “knee valgus” refers to the inward motion of the knees towards midline of the body. If we are going to analyze the safety of valgus we need to have a better understanding of what it is. I propose the following definitions of three different types of knee valgus.
First, DYNAMIC KNEE VALGUS refers to the UNCONTROLLED inward movement of knees during movement. To be categorized as knee valgus, the knees must move inside of an imaginary line drawn from the hip to the ankle, as show below. Dynamic knee valgus often results from poor ankle mobility or gluteal activation during tasks such as jumping and squatting. Athletes demonstrating this uncontrolled valgus do so at both high and low loads.
When research studies demonstrate a correlation between valgus and injuries, this is the motion they are describing. This is unquestionably a bad motion and coaches should address this movement fault.
Up next is a VALGUS MOMENT, in which the knees move towards the midline but do not cross that imaginary line between the hips and ankles. This is often misinterpreted as an actual valgus position but careful examination will show the knees not traveling inside the imaginary line running between the hips and the ankles. I see no problems at all with this movement.
Something I see often is an incorrect understanding of knee valgus. Knee valgus is when the knee crosses an imaginary line that is drawn from the center of your foot to the center of your hip (from the perspective where the foot is pointed at the camera, similar to as shown). Any position on the line would be neutral, any position outside the line would be varus, and any position inside the line is valgus. In my last few squat posts, every video makes it appear that my knee is crossing into valgus when I ascend out of the hole. However, this angle shows that I'm starting in varus and move to neutral due to my knee tracking inward (in comparison to the varus that I descend with). The more you know 🌈🌠
Finally, I believe there is a category of CONTROLLED VALGUS where advanced athletes (in my case elite weight lifters) actually move their knees inside of that line during a lift. In these elite lifters, it is my opinion that this movement is advantageous to their sport and probably not a huge injury risk factor due to their ability to control this motion that ONLY occurs at max and near-max loads.
Elite lifter Mattie Rodgers does this in many of her lifting videos (and I'm certainly not going to blame this on weak glutes)!
The loading is an important component to this as we typically only see this at very high loads. These high level athletes have proven to have sufficient mobility, stability, and motor control to perform a proper squat. They also don't demonstrate this valgus movement during more dynamic tasks like jumping. So why do they demonstrate the knee valgus movement at heavy loads? I believe it is a result of a forceful quadriceps and adductor magnus contraction and is a motion that allows for stronger contraction of the glutes. Let’s explore this more….
If you sit on your bottom with your legs stretching out in front of you and contract your quads what happens? In the video below you’ll see that a quad contraction also causes internal rotation of the hip (credit Bret Contreras for this idea). So wouldn’t it make sense that as a lifter pushes maximal weight, generating as much force as possible, some inward movement happen as a result of the quads?
Recent research by Vigotsky and Bryanton has also found that "The adductor magnus appears to play a pivotal role in hip extension during the squat, producing, on average, more than 50% of the net hip extension moment."
Thus, a strong contraction of the adductor magnus to produce hip extension will also produce an inward movement of the thigh.
I also believe that the inward movement of the thigh may let the lifter take advantage of a stretch-reflex that allows the glutes to help propel heavier weight upward. The inward movement of the thigh will slightly stretch the glutes potentially allowing for increased force production to help the lifter drive up and out of the deep squat.
A similar effect is often observed in very quad dominant lifters. You’ll see them shoot their knees forward during a squat to do the same. This knees forward movement allows the athlete to use that stretch shorting cycle to re-load the quads as they rise.
My belief is that the knees in movement in elite lifters during maximal loads is the result of strong contractions of the adductor magnus and quads, as well as a mechanism that may allow the lifter to take advantage of a stretch shortening cycle to further load the glutes and thus move more weight. Is it the safest position for them to move into? Probably not. While this knee valgus movement is not how I teach people to lift, I certainly won’t coach the elite lifters out of that movement.
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