To Dynamic Valgus - Or Not to Dynamic Valgus? That is the Question

Ann Strother

I was recently watching a Medbridge video on knee injuries when this image appeared on the screen.  HEY!  That's Ann Strother!  Hey girl!  A UConn Women's Basketball star overlapping with two of my years there as team manager, professional basketball player in the WNBA for a few teams while I was working for the Connecticut Sun, on my list for top 10 most beautiful three-point shots, and for sure one of the kindest people on Planet Earth - I was so excited to see her on the screen - except that it was with regard to knee injuries. 

The video was discussing her inverted "V" position called knee valgus which, according to several research articles (like this 2005 paper, and this 2003 paper, and this 2018 paper) may be one of many factors that increase risk of ACL injury in female athletes.  Medbridge had used this image demonstrating her continuing to exhibit this "faulty pattern" after already having had torn and rehabilitated from tearing her ACL. Ann tore her ACL during her sopomore year of high school.  Despite the injury, she was the 2002 Gatorade High School Basketball Player of the Year (her high school senior year) before heading to UConn where she was ultimately a two-time NCAA National Champion.

Kevin Durant

Anyways - seeing her on my computer made me think back to a few weeks earlier when I headed to California to see the Golden State Warriors play against the Los Angeles Lakers only for LeBron James to be out for the night.  I wrote about that here, but while watching the game, I observed that same knee posture repeatedly demonstrated by Kevin Durant of the Golden State Warriors.  See how he's standing at the free throw line about to shoot with his knees almost touching and his feet wider than his shoulders?  He does this a lot.  It's the same position.  While sitting at the game, I snapped this shot and sent it to all my favorite physical therapists and my current student in the clinic... because this knee position is repeatedly considered to be a big problem.

So... is it really a problem?  According to a lot of research, as I've previously mentioned, yes it is because of it's increased risk for injury.  But... is it a problem for Kevin Durant?  Should we be correcting this position in all of our patients who exhibit it?  Is it still a problem for Ann Strother, who I'm pretty sure is not currently playing basketball... but is still running around chasing after her two young children?  What I'm saying is - does every person who shows up in the PT clinic with this presentation need to have it "corrected" or do only some of them need to change it?  Or should we not be correcting it at all?  ACL injury prevention programs constantly work to strengthen the body to prevent exhibiting this type of movement and in PT school we're trained to squat "perfectly" without showing this pattern.  I'm constantly telling my patients to keep their knees out...but half of the time I'm wondering if it really matters. This is the movement pattern I see DAILY in my patients at Seattle Children's Hospital, most frequently in teenage girls who have knee pain, but certainly in boys and in all ages and with varying conditions.  I can tell you from experience that changing the squat position so that they don't do this inverted V is usually much less painful in many of these patients.  I can't tell you that training them to move without the V will prevent them from having an injury later on in life.

So what do we do about it?  As Robert Frost says, "Two roads diverged in a wood..." There appear to be different approaches to dealing with this presentation.  On the one hand, you can work to strengthen and reinforce a more "sturdy" pattern with the knees more straight above the feet rather than angled inward.  Glute strengthening, squatting, and training "proper" jump and landing form tend to be the typical components of a rehab program that works on this pathway.  Repeatedly trying to target a better posture and moving away from this dynamic valgus presentation is a common treatment approach. 

But Kevin Durant is paid about $30 Million per year... do you think he's going to let me change his free throw shot form?  Or anyone on his sports medicine staff for that manner?  Is he actually stable in this position?  Does he train in this position?   So the other option, that some people are now advocating for, is to train into these "suboptimal" positions on purpose.  There are recommendations to purposefully train ankle mobility and control into the position that is common for ankle sprains, particularly in those patients who have already sprained an ankle.  the thought process here seems to be that you can purposefully move into these patterns and try to develop control there so that you're less likely to injure yourself if you end up in that position.  In my search for literature on this approach, I came up empty-handed for scientific papers.  I know that when I injured my ankle years ago, putting it into the position of injury was painful and I wouldn't want to put myself there... years later I still don't purposefully do that motion... but if I play sports and accidentally end up there, I could see how I might be risking injury because I haven't trained my body to tolerate the position.  I did find some non-scientific articles that suggest doing this approach, like this one that discusses the idea of purposefully training into the movement patterns that you were injured in.  There are some people that suggest that if you don't train the injury pattern, you won't be resilient enough if life or your sport puts you into that position and you'll suffer another injury. 

And so...to dynamic valgus or not to dynamic valgus... that is the question. I'm here to tell you that I don't know the answer.  There's not enough evidence to support one way or the other - though there is definitely evidence showing that this position increases risk of injury - so the two approaches both suggest we need to be able to either avoid the position or control the position - not just ignore that position.  I think it might be a combination of both approaches.  I'm certainly not about to go give my patients who squat with dynamic valgus heavy load and have them repeatedly use that pattern - because that seems harmful, and as I've already written - we should Do No Harm.  But I'm also not afraid to consider putting people into and out of positions like this inverted V to see what they tolerate and show them that the human body can do some fascinating things.  What do you all think?