You NEED to start training the VMO ASAP!!

A large number of studies have already established that stronger quads = less knee pain (Slemenda et al. 1997, Hurley et al. 1997, Lewek et al. 2004 ). But what if we could get more specific with that knowledge? What if we could help our clients and patients know exactly what needs strengthening to have the greatest impact on knee pain, OA, and potential surgeries down the road? Thankfully, research has come to the rescue! This research confirms what trainers such as Charles Poliquin, Louie Simmons, and Ben Patrick have been saying for years — that the Vastus Medialis Obliquus, or VMO, is the king when it comes to knee health.

As a refresher, the VMO is that teardrop shaped muscle on the inside of your thigh. Although it is part of the quadriceps muscle group which straightens your knee, the fiber orientation of the VMO means that it acts as more of a powerful stabilizer and less of a knee extender.

It used to be passed around as common knowledge that the VMO couldn’t be isolated in training. Past studies have experimented with various squat types and hip positions to isolate the VMO but to no avail. What all these studies had in common was that they only trained knee extension from a maximum of 90 degrees knee bend (Smith et al. 2009). Interestingly, research in 2016 appears to suggest that when a knee is taken to around 140 degrees of flexion, the VMO is proportionally activated to a greater degree than the vastus lateralis, the force of which the VMO works to counteract (Marchetti et al. 2016). So with the old VMO folklore out of the way, let’s dig into why we all need to make VMO-specific training a major focus of our leg-day programming.

A Bigger VMO is more protective of knee cartilage

One of the hallmarks of knee OA is joint space narrowing, which is the result of the slow (and sometimes fast) degradation of the cartilage in your knee over time. This begs the question: what causes the breakdown of the cartilage in the knee? The easy assumption (and indeed past advice) is that excessive load on the knee joint is likely the cause and that things like heavy squatting should be avoided as they put lots of pressure on the knee and all of its components.

This assumption is directionally not completely wrong, it just misses the mark on the causes and what can be done to address joint space narrowing. While there are many factors that can contribute to this shrinking of joint space, it turns out that one of the highly modifiable ones is quadriceps muscle weakness. As previously noted, studies have shown that quad strength and knee health have a positive relationship, meaning the stronger your quads, the healthier your knees. Pretty simple, right? But why? This positive relationship exists simply because a stronger quad will help control the speed at which your knee experiences what are called “impulsive forces” (or sudden large impacts) such as when your heel strikes the ground when walking or running (Mikesky et al. 2000). Interestingly, it is the rate at which the impulse happens that is the driver of knee cartilage damage, not the amount of the load (brandt et al. 2016). Put simply: control the load, control the damage.

Recent research has gone a step further to identify the VMO as a primary player in helping to protect medial knee cartilage volume, and therefore joint space as well (Wang et al. 2012). This study showed that in patients with knee OA, those who increased the size of their VMOs over a two year period had significantly less knee pain and cartilage loss than those whose VMOs had gotten smaller. This same study also found that this increased VMO size also reduced the risk of knee replacement over a four year period.

A Stronger VMO improves patellar tracking.

Though this article is primarily about the VMO, we can’t forget about it’s counterpart the Vastus Lateralis, which is the largest of the four quadriceps muscles. This big muscle, located on the outside of your thigh, is an important extender and stabilizer of the knee. In the presence of knee pain, the vastus lateralis becomes more dominant and, as its name suggests, it imparts a lateral, or outwardly-directed pull on the knee cap. This pull is greater than the medial-directed pull of the VMO. The net result? More pressure on the lateral cartilage of the knee, and more knee pain over time. Once again, the solution here is simple: restore VMO strength to improve patellar tracking (Makhsous et al. 2004).

Great, but HOW?

As discussed above, we’ve put to rest the notion that you can’t selectively train the VMO. Strength trainers have known for decades that this wasn’t true, it just took research years to have the courage to squat low enough to “discover” the truth. In order to target that teardrop shaped muscle on the inside of your thigh, you simply need to bend your knee to around 140 degrees and apply load. Put another way — just squat deep. Get as low as you can safely go without pain.

There’s quite a few options for getting into VMO territory on your squats, as outlined by The KneesOverToesGuy himself, Ben Patrick. Pick the one that works best for you and build it into your weekly routine. I suggest taking all of your squats to depth if possible.

Of course not everybody will be able to achieve full knee flexion right away (or perhaps ever — if they’ve had a knee replacement), and that’s okay. If you need help, find a trainer or physical therapist that has the know-how to get you there. A great way to start is over at ATG Online Coaching. This is Ben Patrick’s coaching platform that also happens to be staffed by expert deep-squatters that can help you achieve that full knee bend that your knee has been begging you to get all these years!

Happy Knees, Happy Life!

References

Brandt, K. D., et al. “Yet more evidence that osteoarthritis is not a cartilage disease.” Annals of the rheumatic diseases 65.10 (2006): 1261–1264.Hurley, Michael V., et al. “Sensorimotor changes and functional performance in patients with knee osteoarthritis.” Annals of the rheumatic diseases 56.11 (1997): 641–648.

Lewek, Michael D., Katherine S. Rudolph, and Lynn Snyder-Mackler. “Quadriceps femoris muscle weakness and activation failure in patients with symptomatic knee osteoarthritis.” Journal of Orthopaedic Research 22.1 (2004): 110–115.

Makhsous, Mohsen, et al. “In vivo and noninvasive load sharing among the vasti in patellar malalignment.” Medicine and science in sports and exercise 36 (2004): 1768–1775.

Marchetti, Paulo Henrique, et al. “Muscle activation differs between three different knee joint-angle positions during a maximal isometric back squat exercise.” Journal of Sports Medicine 2016 (2016).

Mikesky, Alan E. et al. . “Relationship between quadriceps strength and rate of loading during gait in women.” Journal of Orthopaedic Research 18.2 (2000): 171–175.

Slemenda, Charles, et al. “Quadriceps weakness and osteoarthritis of the knee.” Annals of internal medicine 127.2 (1997): 97–104.

Smith, Toby O., et al. “Can vastus medialis oblique be preferentially activated? A systematic review of electromyographic studies.” Physiotherapy theory and practice 25.2 (2009): 69–98.

Wang, Yuanyuan, et al. “Increase in vastus medialis cross‐sectional area is associated with reduced pain, cartilage loss, and joint replacement risk in knee osteoarthritis.” Arthritis & Rheumatism 64.12 (2012): 3917–3925.