Valgus Knees and Why RG3's Career is At Risk

Robert Lee Griffin III. Winner of the 2011 Heisman Trophy. Second overall pick of the 2012 NFL Draft. Signed by the Washington Redskins in a four-year, $21.1 M contract (with a $13.8 M signing bonus). Voted NFL Offensive Rookie of the Year in 2012. Blew out his knee in 2013.

Something doesn't follow here. While football is a notoriously violent sport, how does a Heisman winner and 2nd overall Draft pick suffer such frequent and catastrophic joint injuries? Take a look at these photos from RG3’s 2012 combine, and the answer becomes quite clear:

Notice how his knees cave in as he takes off and lands his vertical and broad jump attempts. This is called valgus knee collapse, and this is poor mechanics. And while I’m sure there are other mitigating factors in RG3’s injury-ridden career—after all, direct hits to your knee by 300-lb defensive linemen don’t exactly do wonders for your ACL—his poor knee mechanics, cemented through years of practice, have cost him playing time and could, one day soon, cost him his career.

Why do so many professional athletes, and not just football players, have their careers cut short due to preventable knee injuries? And looking specifically at women, why do so many female athletes experience recurring or chronic knee pain while running? The answer to both questions lies, in part, to the mechanics of the knee. Understanding how your knee is designed to function is the first step in reinforcing good movement patterns—and preventing career-ending injury.



To understand how the knee is supposed to work, we first need to understand the relationship between the knee and the hip. Now this may come as a shock, but men and women are biologically different. (Gasp!) Let’s deviate from the, ahem, obvious differences and talk about the Q angle in men and women. Women have bigger hips than men because we were designed to have babies, and babies have big ol’ heads. Our hips HAVE to be bigger in order to perpetuate our species—it’s science! Therefore, the angle between the hip and the knee—called the Q angle—is larger in women (around 18 degrees) than in men (around 12 degrees).

While the difference may seem minor, the Q angle actually factors heavily into knee function. The patella’s ability to track in a straight path is determined by the quadriceps’ angle of pull—and if this angle is too great, as happens in athletes with a larger Q angle, the quadriceps can pull the patella in a more lateral direction. And as you can imagine, too much lateral pull on your kneecap can cause quite a bit of pain in the soft tissues and cartilage surrounding the knee joint.

Since our Q angle is greater, it is easy to see why women often experience more knee pain in activities reliant on proper repetitive knee action—such as running. In fact, if you look at the female Boston Marathon winners over the last decade, you’ll see women with narrow pelvises (and smaller Q angles). Interestingly, 9 out of 10 of these women are from East Africa—Kenya and Ethiopia—and physiological differences among races show black women generally have narrower pelvises than white or Asian women. (It has to do with the average cranium size of babies among different races; black babies are usually born with smaller heads. You can read a fascinating research paper on this topic here.)

So if we extrapolate from this data, we can conclude that athletes with smaller Q angles are generally better suited to running than athletes with larger Q angles. Which makes sense when you think anecdotally: how many female runners do you know with recurring or chronic knee pain, compared with male runners? In an outdoor boot camp I ran this summer, I estimate 50% of my female participants experience, or have previously experienced, knee pain or injury. Women, with our big baby-making hips, are simply more biologically prone to bad knee mechanics. 

But simply because men, with their svelt little hips, are not as prone to knee dysfunction does not mean they are immune to it. Just as genetic factors contribute to improper knee mechanics, so do repeated ugly positions that result in valgus knee fault.



The ACL helps you cut, plant, and pivot without exploding your knee.

The ACL helps you cut, plant, and pivot without exploding your knee.

Nobody likes valgus knee collapse. It can lead to all sorts of nasty stuff: patellofemoral pain, IT band syndrome, and, in RG3’s case, ACL tears. The ACL (anterior cruciate ligament) helps stabilize the knee when you cut, plant, or pivot in sports—making it a pretty necessary component for a long athletic career, ESPECIALLY for football players. The ACL connects your femur to your tibia in a cross-like pattern (hence “cruciate” ligament), just like crossing your middle finger over your index finger. If you were to rotate your middle finger further over your index finger, the connection between the two becomes stronger—but if you were to unwind or untwist your middle finger away from your index finger, the connection is lost. This is what happens to the ACL when you run, jump, or land with knees valgus. With knees pointed inward, the ACL gets untwisted—and unstable. Just watch this clip, if you dare, of RG3’s awful ACL tear during the 2013 Wildcard game against the World Champion Seattle Seahawks (MOM, SKIP THIS PART!):

You can almost hear the insidious snapping of that critical ligament as his right knee turns inward and loses all stability. 

So now that we know what improper knee mechanics looks like, in excruciatingly slow-mo replay, let’s talk about some concrete ways you can avoid RG3’s injured fate.


Ever had pain on the inside of your kneecap while running? Stand up right now and look down at your feet. Are they both pointed straight forward? If not, you might be putting yourself at risk for knee injury. Duck feet, feet that turn outward when you stand or walk (also known as a condition called pronation), can make for painful, yucky knees. Imagine you're a racecar: what would happen if your front two tires pointed outward instead of forward? You probably wouldn’t get very far before the uneven wear wreaked havoc on the front axle. A similar thing happens when you try to run with duck feet. When your feet are pointed out, you land unevenly on the bones of your foot, putting stress on your medial ankle and causing unnecessary torsion at the knee joint. Doing this repeatedly—like on your daily 5-mile jog, or off-season aerobic conditioning—will train your body to adopt poor knee mechanics, so that your knees naturally learn to collapse into unstable positions all the time.

Which is worse: duck face or duck feet?

Which is worse: duck face or duck feet?

The ONLY good thing about duck feet is that you can FIX the problem! While different people pronate for all sorts of reasons, here are my top 3 concrete steps you can take TODAY to fix your faulty knee mechanics, cure your knee pain when running long distances, and make the most out of your NFL career.



If you're a regular reader, you know how obsessed I am with your butt. If your glutes are tight or weak, it will affect the function of your knees. It might be time for you to revisit my Butt Talk article, which lists some specific exercises targeted at strengthening the gluteus medius muscle that helps stabilize your pelvis and prevent valgus knees. Show your butt some love.



Your knees, marvelous creatures that they are, will find a way to compensate for all sorts of faulty mechanics. If your ankles aren’t flexible enough to support a heavy back squat, for example, your knees will compensate by collapsing inward. Take a look at my article on the calf muscle (which connects to the ankle) to learn specific stretches for improving your ankle mobility.



It almost goes without saying, but you gotta practice putting your body into good positions. This means reminding yourself to turn your toes forward when you walk or run. Even if it feels unnatural and hard—you still gotta do it. When squatting or jumping, pay attention to the path of your knees as they bend and don’t let them fault valgus. By making yourself aware of your own mechanics and forcing your body to practice good positions over and over and over you will help neuromuscularly cement proper knee function, so that your body naturally defaults to healthy and safe positions.



RG3's catastrophic knee blow-out didn’t start on the field—it started years earlier, in the weight room. Not strengthening the muscles that help correct valgus knee collapse and continually practicing unstable positions helped make RG3’s body so vulnerable. What you do off the field is every bit as important as what you do on it, and making the choice to attack your vulnerabilities in the off-season will only make NEXT season that much better.

And don’t even get me started on RG3’s dislocated ankle.

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Christye Estes, CSCS, ACSM-CPT, is one of the regular contributors to the Volt blog. She is a CSCS-certified strength coach, a certified personal trainer through the ACSM, and a Sports Performance Specialist at Volt.
Learn more about Christye and read her other posts | @CoachChristye