Role and Rehabing VMO

The accepted primary role of the VMO is in contraction to screw home the knee joint through the last approx 15 degrees of extension.
But in sprinting it’s role is IMO very much an eccentric action at top speed in the transferral of vertical force.
This is not the accepted view in general academic/therapy literature

My questions for Charlie are how does the role change from the acceleration phase and is there as much or more activation at this stage?

I have had two athletes present with knee pain and the patella seems to be trackking incorrecty and it’s because the VMO is not strong enough to hold it in position and seems to be weak(ening).

Now the ITB and VL are tight - true, but I’m wondering if there is a training pattern/action that is affecting the VMO firing.

The only thing I can think of is that

  1. The 2 guys slight lordosis and
  2. both told me they squat with heel raises

I’m rehabbing both and working on reducing intra and inter muscluar tension along with incresaing flexibility and will start strengthing VMO next.

I’m just looking for clarity on the role of VMO in high speed - not normal conditions.

What about the balance beetwen ITB/Sartorius?
Gluteus and psoas?
Do you have made any muscle tests?

try using ems or tens to strengthen vmo, i had good results, and also get some deep tissue work done on the surrounding muscle’s

Squating with heel raises could be a problem. the VMO must be working both for acceleration as well as top speed. EMS is the best option- but no fooling around there! The contraction must be sufficiently strong to really work the muscle. I would describe it as a contraction sufficiently strong so as to leave an airspace between the recipient’s entire body and the table for the duration of each contraction!

There was an article in one of Jess Jarver’s Sprint books that examined the activity of various muscles during sprinting. In a nutshell, they concluded that, as velocities increase, there is a greater demand on the VMO due to the need for increased stiffness at ground contact.

Yes, as it has an eccentric role (prob why it wastes away faster than the other quad muscles), but it stabilizes all the time.

charlie. I’m a thrower so if i was to use a 6 second contraction for my vmo, is the buildup period included in the 6 seconds, or is it 6 seconds after it has built up to full contraction?

no23, you have a what-came-first scernario(sp)here. Are there any under-lying sub-patella pathologies that have created the knee pain, lateral (I’m assuming) tracking, and VM atrophy?
Or, was there a co-current or prior lower leg, ankle, foot injury? Are the gluteals firing well? Is the ITB “short” bilateraly? Muscle doesn’t atrophy or loss strength without a reason behind it. I would suspect the VM has atrophied/weakened due to training errors, such as insufficient depth in squats and/or sub-patella knee joint injury. Cartlage lesion, chondramalicia, subluxation, meniscal tear etc…
The major role of the VM is to “tighten” or “compress” the patella onto the femur in the last few degrees of knee extension. The VM also works hard coming out of a deep knee bend. If you have knee pain, going to a full, contracted knee extension creates more pain. Therefore, people avoid the last few degrees of extension, the VM doesn’t have to work and atrophies.

Charlie, greetings. The VM does play an eccentric role in running/sprinting. I know you where refering to it’s role in sprinting but in cycling it would have an concentric role. Can’t argue the development of elite cyclists lower quads.


My experience is with the running events, so perhaps that’s when the workload on the VMO is reduced so much. Does the VMO waste away as relatively quickly when a cyclist is layed up?

We always used a very short rise time- about .75 sec and we included it in the break. for a shot putter, I think a 6 sec contraction would prob still require at least close to the 50 sec breaks between.

Charlie, I’ve never worked on an elite cyclist but once they are off the bike they are just like you and me. Off the bike the role of the VM changes to a primarily eccentric characteristics except in stair climbing, rising out of a low seat or deep knee bend. If there is knee pain in the last 20-15 degrees of extension, and terminal extension and/or a strong contraction of the VM is avoided, the VM will atrophy. This would be evident in a person who has changed their gait to compensate for the pain. Hence the “tightness” and shortening of the ITB, other knee extenders and contracture of the adductors. Particulary true for an athlete who tries to work through the pain.

I think the reason for the atrophy is disuse or a weak contraction due to pain.


I wasn’t sure if you meant there was a difference. Thanks for clearing that up.

Yes I’ve been thinking its the heel raise preventing full knee extension.

I’ll make sure not to be standing in front of the guys when I turn the EMS on!!

I’ve checked all the areas I can see, looked for postural issues, trackgin, heel abnormalities and all still seems to be leading me back to the heel raise.

The other thing is, both these guys are squating heavy, so the actual effect of insufficient knee ext. is quite great.

Yes both ITB and Vastus Lat are tight along with Glute medius - but which comes first?

I’m working on these and also started with direct VMO strength work and EMS.

Just one further question on something you said “The VM also works hard coming out of a deep knee bend”
So in deep squat position you say VMO is also firing?

Where the athletes generally find it sorest is on loaded full knee extension

While VMO may have some input in stair climbling, are the main groupings not the hip extensors therefore eliminating the role of VMO if it is weak?


Where the athletes generally find it sorest is on loaded full knee extension

Sub patella pain at terminal, loaded knee extension? Very high compressive forces at that time.

While VMO may have some input in stair climbling, are the main groupings not the hip extensors therefore eliminating the role of VMO if it is weak?

The hip extensors work in conjunction with the quads, hamstrings, etc… to climb stairs. I don’t think you could necessary or even if its important isolate which muscles are firing more to climb stairs. Even so, it would be an individual, postural, habitual situation differing from one person to another.

Anyway, yes. The hip extensors would play a greater role if there was VM/quad weakness. And there may be a greater activation of the trunk musculature and ipsilateral or contralateral triceps to assist on the handrail.


Do you have seen this tights with specific muscle tests or palpation?
Work on lateral fascia, probably there is a feet problem or simple muscle overuse imbalance.