No…it can’t be….say it isn’t….the dreaded….KNEE VALGUS!
*cackles and screams echo in the distance*
I’ve written about knee valgus before but I wanted to write a quick post today to highlight the sinister complexity of this movement pattern.
Knee valgus is the position in which the knees move inward from their normal alignment. It should not be confused with genu valgum which is often used to refer to a pathological condition in pediatrics that affects the shape of the involved joints. We are talking about adult physiologic knee valgus - it is primarily the result of strength and motor control (meaning muscle capacity and the ability for the brain to accurately turn on muscles when needed).
What is the immediate risk?
The primary concern with knee valgus is that, due to the position of the femur and the tibia, a very important ligament in the knee is put on high strain. What's the one knee ligament most of you have probably heard of? Yup - the ACL (anterior cruciate ligament). Numerous studies have found that non-contact ACL injuries are overwhelmingly accompanied by knee valgus collapse (note: there is some discussion that this is especially true for female-bodied athletes and men might need to also be aware of loading on a fully extended knee, but more on that at another time).
ACL injuries should be avoided at all costs. Pain aside, proper rehab from an ACL surgery is at least a year and many struggle to ever reach their previous level of performance and confidence. That should be enough reason to learn how to avoid knee valgus.
Also, while this is an injury usually associated with court and field sports, almost EVERY discipline needs to be aware of this. Here are a few ways knee valgus might pop up in your sport:
Gymnastics: launch and landing mechanics
Weightlifting: These folks know what I'm talking about - when you put just a few too many pounds on your squat bar and those knees start to wobble inwards...yup, that's knee valgus
Rock climbing: landing from a fall off a bouldering wall
Partner acrobatics: base knee position during pitches, flyer position during any standing flip
Ping pong: yup! bracing that back leg to deliver an excellent forehand smash...
You get the idea - almost all sports involve loading mechanics through the legs, and that means knee valgus can pop up. Additionally, ACL injuries or other knee instability injuries are associated with increased rates of osteoarthritis down the road, so a bit of work now can increase your mobility in your old age.
What "makes up" knee valgus?
Three main components comprise this position:
1. Femoral internal rotation / adduction: the femur is not positioned correctly, leading to excessive adduction and some internal rotation
2. The tibia is externally rotated relative to the femur
3. The foot is assuming a pronated position (rolling inwards), often accompanied by a collapse of the medial longitudinal arch
There is often debate among clinicians as to whether or not the bad hip mechanics (femur motion) lead to the bad tibia/ankle mechanics, or whether or not it is the other way around. From a treatment standpoint it does not matter *too* much as both will need to be corrected.
Am I afflicted???
To find out whether or not you've caught the virus start filming yourself while you do squats, land from jumps, or play your sport. If you see your knees drift towards each other, or the inside arch of your foot begins to collapse inwards, you might want to work on this.
What Can I Do?
The work of Dr. Christopher Powers has highlighted the relationship between ACL injuries and gluteal muscle insufficiency. Across numerous studies he has developed ideas that persuasively recommend training of gluteus maximus and medius (the main hip extender and the main hip abductor) to help correctly position the femur and prevent valgus collapse. There are many ways to prophylactically increase your glute awareness and engagement.
Here are some of my favorites:
Note: Probably 95% of people out there do the clamshell wrong. If you let your hip roll back at all during this movement you will likely start using your tensor fascia latae muscle instead. This is a problem for a number of reasons I'll explore in another post.
Additionally, while there is not as much research on the subject, I find that collapse of the medial longitudinal arch often accompanies this pattern. You can start to work on conscious control of the small muscles that help support this arch with the following drill:
This one is trickier than it looks! Try to accomplish this without curling your toes or lifting the ball of your foot off the ground.
Knee valgus is a tricky beast - it is hard to notice unless you really look for it and it isn't at all a problem until things go awry and it is too late.
Get on top of your prehab and risk factor identification now to avoid lots of problems later on!
If you want to explore this with a professional reach out! You can contact me by emailing info@smartmovementpt.com or set up an appointment HERE. If you do not live near me in the Bay Area I do tele-visits utilizing video chat to discuss all of this and provide analysis and coached exercises in addition to in-person visit options.