The Real Fix for Knee Valgus

The real fix for knee valgus actually isn’t to place a band between the knees, although this is still a common strategy we see employed all over social media.  The use of bands to cue movement is nothing new, but as with anything in the industry, tools have a tendency to be applied without the essential critical thinking about the reasons behind their use.

For example, a common strategy to fix knees caving in during squats is using a band around the knees to help cue “knees out”.  Another example is using a band at the knee on a split squat to pull the knee in, also to cue “knee out”.

The idea behind using bands as feedback is that if we exaggerate the fault, it will cue the client to correct the fault.  The client will need to work harder to overcome the additional resistance of the band.  If we place a band around the knees, we cue people to push the knees out harder to prevent the faulty mechanics of the knee caving in, right…?

But the problem isn’t always mechanics, and specifically it isn’t knee mechanics.  Sometimes the problem is strength elsewhere.

 

Does applying resistance to something that’s already weak sound like a good idea?

 

I should hope not.

 

YOUR KNEE IS BETWEEN YOUR FOOT AND YOUR HIP

Granted, that statement is at best, considerably basic anatomy.  What I really mean to say is that the knee being an intermediate joint, it highly depends on the hip and the foot for optimal alignment.

A study by Bittencourt et al. (2012) analyzed the contribution of forefoot alignment, passive hip internal rotation and hip abduction torque to frontal plane knee projection (or knee valgus) angles during a single-leg squat and in landing from a vertical jump. The first predictors of high frontal plane knee projection were hip abduction torque for the single-leg squat, and forefoot alignment for the landing task.

This just goes to show the importance of both the foot and the hip in optimal knee alignment.

 

The foot

There is an intricate relationship between the foot and the hip where motion of the foot is translated proximally to the hip and motions of the hip, distally to the foot.  As you can imagine, this drives a net effect at the knee.

These force couples are an important notion to be aware of.  Dorsiflexion and eversion are coupled with internal rotation of the tibia and the hip and plantar flexion and inversion are coupled with external rotation of the tibia and the hip.   Foot pronation is a combination of dorsiflexion, eversion and forefoot abduction.  If someone has excessive pronation or does not control pronation, this will create internal rotation at the tibia and hip, and the knee has nowhere else to go but in.  Placing a band between the knees is not likely to fix the foot stability issue, as a matter of fact, it likely perpetuates it.  Take a look at the position of the person’s feet in the image below.  Nevermind that she is not in ideal footwear, but do the feet look like they are in a stable position to produce force into the floor?

 

squats with bands image

 

If you want to read more on foot function, make sure to read my article Foot Stability is the Foundation for All Your Lifts.  I also suggest you check out Dr. Emily Splichal, who will also be a guest expert in our upcoming Masterclass with a lecture on the foot.  (Stay tuned for the Masterclass, launching August 1st on Rehab-U.com)

 

Hip mobility

An interesting finding in the Bittencourt et al. study was that passive range of motion in hip internal rotation also plays a role in increased knee valgus (image from article).

 

passive hip IR image

 

Essentially, passive hip internal rotation was a measure of hip stiffness.  If the internal rotation torque produced from the mass of the lower leg allows for high passive internal rotation range of motion, this represents relatively low stiffness of the hip.

As previously mentioned, hip abduction torque was the main predictor of knee valgus where:

 

Low hip abduction torque X High passive hip internal rotation = Increased knee valgus

High hip abduction torque X High passive hip internal rotation = Decreased knee valgus

 

In a nutshell, this means that if someone has high passive hip internal rotation (or low stiffness), they need more hip abduction strength to prevent knee valgus.

 

Hip abduction torque

Another common use of bands around the knees is to target the glute med.  However, as the hip moves into flexion, the anterior fibers of the glute med actually reverse their rotary action and become hip internal rotators.  Further, the study by Bittencourt et al. (2012) also showed that there was no significant increase in glute med activation with the use of bands during squats.

XPN World bannerOn the other hand, all of the fibers of the glute med are primary hip abductors, regardless of hip flexion angle.

If hip abduction torque is important, does that mean people should be doing band shuffles and Monster walks? I discuss this in another article on my blog…

When the foot is planted on the ground, the glute med’s function is to maintain frontal plane (or lateral) stability of the pelvis.  Hip abduction exercises work well to identify, isolate and contract the glute med for better mind-muscle connection, but

 

closed chain exercises actually produce higher levels of activation and better represent the actual function of the glute med

 

As a matter of fact, during a band side-stepping exercise, the support leg has been shown to have higher levels of glute med activation than the stepping leg.

The Stork exercise and single-leg holds shown in the main video of this article are effective exercises to tap into this closed-chain activation and frontal plane stability.  Make sure you watch the main video to see how these exercises are done.

 

LOOK UP AND LOOK DOWN

The use of a band between the knees during squats is a strategy we still see and is typically used with inexperienced lifters because they tend to let the knees cave in during squats.  However, a recent study by Reece et al. (2020) showed that the use of a looped resistance band at the knees during squats actually increased knee valgus, particularly in people not accustomed to using it (the subjects in this study had not squatted with a resistance band before).  Are these not the exact people being targeted for the use of bands between the knees?

These results are in part due to the fact that subjects lacked the abduction strength to overcome the resistance of the band. As I mentioned previously, it’s no surprise that applying resistance to something that is already weak would not offer optimal results.

Because the knee is an intermediate joint, we need to look at the foot, ankle and hip as precursors to movement errors reflected at the knee.  Deferring to the use of bands at the knee to drive movement is not likely to produce the desired results, and may in fact mitigate the process.

 

 

REFERENCES:

Reece, M., Arnold, G., Nasir, S., Wang, W., & Abboud, R. (2020). Barbell back squat: how do resistance bands affect muscle 
activation and knee kinematics?. BMJ Open Sport & Exercise Medicine6(1), e000610. doi: 10.1136/bmjsem-2019-000610

Bittencourt, N., Ocarino, J., Mendonça, L., Hewett, T., & Fonseca, S. (2012). Foot and Hip Contributions to High Frontal 
Plane Knee Projection Angle in Athletes: A Classification and Regression Tree Approach. Journal Of Orthopaedic & Sports 
Physical Therapy42(12), 996-1004. doi: 10.2519/jospt.2012.4041

Neumann, D. (2010). Kinesiology of the Hip: A Focus on Muscular Actions. Journal Of Orthopaedic & Sports 
Physical Therapy40(2), 82-94. doi: 10.2519/jospt.2010.3025

 

 

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Mai-Linh Dovan M.SC., CAT(C)
Certified Athletic Therapist
Founder of Rehab-U

 

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