Runner’s Knee Exercise: Functional VMO Strengthening

The simple knee strengthening exercise demonstrated in the video above is a real favourite of ours for helping those with running related knee pain build strength in a small but important section of the Vastus Medialis muscle, Vastus Medialis Obliquus (VMO).

N.B. I do appreciate the current debate surrounding VMO – I use the term as many runners will be familiar with it. For the sake of this post, you could also read ‘inner-range quads’ in place of ‘VMO’. For more on the VMO debate, read the comments thread below this post!

The VMO muscle is situated to the inner part of your knee. It forms part of your lower Medial Quadriceps. It has an important role in helping control the knee’s alignment through movement and loading.

TIP: We show this exercise performed off a step with a wedge. You can recreate the same exercise off the bottom step of a flight of stairs, with a book or two placed under your heel. This gives the same effect as a wedge.

Fix Your Knee Pain >>
Free Rehab Guide [PDF]
Last updated on November 1st, 2021.


  1. I like twist on the old lateral step down, do you find it reduces anterior knee pain? I have used decline squats before with good success. I do question about the “VMO” comment though, not sure this is is even firing the VM greater than VL, VI much less actually the VMO. Thoughts ?

  2. Hi James

    First of all I’d like to say that I love your site and your really useful and helpful advise that you give… for free…

    But… The use of the term VMO (Vastus Medialis Obliquus) I think needs to be used with care.

    As a physio I was first taught as an undergrad, many hears ago now, that the VMO exists & plays an important role in the stabilisation of the patella (knee cap) and its weakness or late firing is a common cause of runners knee pain. The VMO is believed to be a group of muscle fibres that branch from your inner quadriceps group at an oblique angle (hence the name) and provide a counteracting force to the knee cap that helps keep it centred in its femoral groove and so stops it rubbing and causing friction induced pain with repetitive actions like running.


    Recent research and understanding now questions this, Smith et al (2009) conducted a review of all cadaver studies over a number of years and found no evidence for the existence of these oblique fibres of the Vastus Medialis in the vast majority of people.

    The research of if you can selectively preferentially recruit these fibres is also limited and again Smith et al (2009) in another study found no proof that the VM is recruited anymore than the VL in most exercises that us physios prescribe.

    When dealing with runners knee pain, aka anterior knee pain, aka patella femoral pain syndrome I do think that quad strength and control is important, especially the eccentric control which your video demonstrates really well, but I don’t think we can say this is more VM over anything else.

    I think us physios (me included) have a lot to answer for with these pseudo descriptions that we make up from time to time with no real evidence (just a hunch) to support it, and the treatments we claim work. These then get ingrained into soceity thanks to media and press coverage and then are hard to remove once we learn more.

    But I’m confident enough to say now that the VMO doesn’t exist, we cannot recruit it and so its not a treatment option when dealing with runners knee pain, instead eccentric quadriceps and proximal hip and lower abdominal and pelvic control and functional ankle movements are all much more important factors to considers than the ‘fictional’ VMO.

    What are you and your readers thoughts?



  3. I think if you take a look at Jenny McConnell’s research in the mid 90’s she identified altered firing/recruitment of the VMO with her taping methods. Even if we are not calling it VMO any more, EMG studies have demonstrated that the medial section of the quads fires at a different rate to the lateral side during stair ascent and descent. How we manipulate that in the future to best serve control and tracking of the lower limb is open to ideas….but I really love this exercise and think it quality.

    I just really wish that as physios we could become more pragmatic, less philosophical. If it works clinically… Share, shout and let everyone know so that people get the relief they need. The theories about HOW something works are less important to me. If it works, use it. Possibly over simplistic, but keeps things simple for practitioners like me.

  4. Interesting debate.

    I think the most recent research not only disputes convincingly the existence of a separate oblique vastus, but also the lack of an exercise that creates a selective activation of such a component of the quads.
    McConnell early paper of 1986 was nothing more than a review and formulation of hypothesis. For this we should be consider its value as asking the questions but not for providing the answers, which dominated courses in the 1990s. Subsequent experimental studies looking at activation timing, taping etc have been done with varying amounts of rigour but often the lack of controls, placebo etc and blinding create the presence of bias which dilutes the value of the results.

    With regards to the value of exercise in PFPS, strengthening of quads in general and controlling femoral rotation at the hip by means of hip muscle strength has been shown to be of great benefit.

    PFPS has many components including femoral position and anthropometry, trochlea depth to name a couple, and to think that quads control is important above all others is naive in my opinion.

    I have to disagree with the social physios comments, as its important to understand the mechanisms of action of anything that we do, because no intervention helps everything so that’s why research is so important and has to complement the questions and ideas derived from clinical practice.

    It’s very two dimensional to only be interested in what works, and not why it works. The maturity of the profession depends on us asking questions like that, otherwise we are no better than the alternative therapies. Remember that most researchers were once clinicians too, some still continue to have a clinical input.

    I don’t believe it’s a question of philosophy or pragmatism, but it’s about the development of the profession into more science and less art-form, and I do believe the latter is also an important part of what we do, but should not be used to hide form the facts that research and new information gives us.
    Thank you to Adam for presenting the vmo story to date, and to james for presenting the topic to debate.
    Regards to all.

  5. Hi All,

    Thanks for a really interesting discussion so far. I’m always the first to admit that I don’t know it all. One of the many purposes of this blog is to facilitate my own ongoing learning and development as a coach.

    Clearly the referencing of VMO in particular has sparked the above discussion. Adam, you’ve done a great job of bringing us all up to speed with the current thinking on the subject of VMO’s questionable existence, thanks!

    Both Adam and Fizziowizzio have identified Quads strength and control as factors important in the successful rehab of PFPS, so I stand by the exercise choice.

    Interestingly, since my ACL reconstruction 6 years ago, I have noticeably reduced muscle tone in the area we habitually call VMO on my left side. Since recording this video with Brad three weeks ago, I’ve been regularly preforming the exercise at home, and have definitely improved muscle tone in that specific area, as well as quality of eccentric control.

    So whether I call it a VMO exercise (maybe not now!) or an Inner Range Quads exercise… It seems to hit the spot.

  6. Thank u for posting a really great exercise. I had 2 successful lateral releases quite a few years ago and my knees have been a million times better. I was told not to run, but with the help care and support of wonderful people like yourselves I’ve been able to run a lot and completed 2 marathons. Thanku for triggering my VMO memory though as I’ve been neglecting that recently and my knee has flared up a bit!!

  7. After reading around the causes of my Pes Anurine Bursitis this rehab exercise would appear to be an exercise I should subscribe. However, would anyone suggest this exercise over a cortisone injection into the Pes Anurine bursa? Not really keen for the jab but would like to get back running ASAP. Thanks in advance for thoughts. Additionally, special thanks to James, if u we’re living back in the Uk I would definitely be looking you though I am aware of skype consultations.

    1. Hi Andy,


      Re the cortisone injection, I’d make sure you’ve pursued the rehab (exercise therapy) option thoroughly before getting a jab. Inner Range Quads / VMO exercises like this will be well worth your time and effort, as well Glute / Adductor / Hip exercises. Hard to be specific without seeing you.

      I’m still in the UK, working from London one day per week (Sat) and Norwich the rest of the time. Drop me a line…

  8. Bit of a typo there James, sorry. Meant to say if I were back in the uk. Am a 3:15 marathoner but really looking to get under that 3:00hr mark. I’m honing to get to get into some
    Single leg squats and various other strength exercises you have demonstrate so well in your blog. Will definitely be dropping you a an email soon.

    1. Ha, that makes much more sense!

      Norwich is out on a limb, I know… but definitely still UK 🙂

      Drop me a line when you’re back in the country and we can discuss your running.



  9. This is brilliant, thank you so much for the website James. I am not a physio or have a degree in sports science however I do read very widely around my chosen sport of distance running. Your website is essential reading.

    I am in a my fifties with 10 years of club running behind me and like Andy I feel I am a solid 3h15m marathon runner and like Andy would like to dip under the 3hours.

    About 8 weeks ago my physio diagnosed patellar tendinopathy (lots of swelling and pain) and after leg strengthening exercises (obtained from Kinectic Revolution and vetted by my PT) at the gym I am beginning to sense an improvement. I can still only run about 4 miles before the pain kicks in so only running about 2 x 3 miles a week (OMG!). However cycling is fine – any distance for any duration, indoors or on the Watt Bike in the gym causes no pain.

    I suppose my reflections on this are centered around VMO strengthening – in the past my physio (whilst investigating other injuries) always comments on how weak my VMOs appear and has given lots of exercises to strengthen them, yet I still get knee discomfort and now this inflamation. Not sure what to do now in the light of this thread; do I abandon VMO exercises or continue as they may do some good?
    BTW I notice on other websites e.g. BUPA Running they recommend you stretch your thighs and calf muscles regularly as part of rehab for Patellar tendinopathy.

  10. Very interesting
    I have chronic pfs in both knees, had them scoped few years ago but envelope of function is very small.
    I do lots stretching and pt exercise but suffer flare ups when I do too much.
    I’m left just to deal with it which is somewhat frustrating, esp as I’m only mid 40s and was keen footballer and runner.
    Anyway i enjoy ypur tweets and content.

  11. Hi James, excellent work as always. I declare an interest as a fan!!
    I think it’s easy to get hung up on terms and research….when what people want is pragmatic and easy to follow/replicate advice.
    Whether we call it VMO your VT covers many of the functional groups the above comments talk about.
    I’m reminded of the phrase….”how do you know you have a Pilot at your party…..don’t worry he will tell you”!!
    Catch up soon.