Knees Coming in on the Squat: A weak VMO?

[Subsistence]

I was speaking to a PT friend of mine recently and mentioned how I was having a hard time keeping my knees out when squatting at max weights. In my scenario "heavy weights" are around 245lbs3x5.

She said that she had the same issue and it was due to a weak VMO (vastus medialis obliquus). She said that the role of the VMO was to keep the knees in position, and that 95% of the time knees traveled in during squats was due to a weakness here (in the context of people who KNOW their knees should be out but can't keep them there at heavy weights).

She recommended doing "sissy squats" to fix this. She described how to do the exercise as:

Stand on something slanted, so that your heels are above your toes (you must actually stand on something not just your tippy toes) hold a bar behind you. do squats slow ie 4 secs down 4 secs up, 8 reps. your toes can be pointed straight forward for these and your feet do not have to be far apart.

It is also worth noting that this PT has read Starting Strength and highly recommends it and barbell training and has went to weightlifting meets before. She also understood why I would be skeptical of this but said it really seemed to help. This is why I didn't just blow her off as just another moronic PT.

That said, my tendency is to think that this is more likely to be just a technique issue whose basis does not lie in physiology, and that knees coming in is just a common type of form break down at max effort weights.

I was wondering if you had any insight into this either way.

[Mark Rippetoe]

Let's analyze this together, me and you. What keeps the femurs out at the bottom of the squat?

[Subsistence]

Let's analyze this together, me and you. What keeps the femurs out at the bottom of the squat?

I get the impression that this will not end well for me.

I would say the hip abductors. I imagine she would say the VMO, based on her description of it "keeping the knees out" but this is the first time I even heard of this muscle to be honest.

[Mark Rippetoe]

Look up the vastus medialis online and tell me how its contraction can abduct the femurs.

[Subsistence]

Done. If anything, looking at this image:

http://upload.wikimedia.org/wikipedi...s_medialis.png

It seems like if anything, it would serve to pull the knees in, opposed to push them out. The article states: "Much has been made of the ability of the Vastus Medialis to translate the patella medially, however since approximately 70% of the contractile fibres attach directly to the common extensor tendon (which then inserts centrally to the superior patella) the functional ability to achieve this goal may be overstated".

So if I am not mistaken, if the muscle did ANYTHING in relation to knee position, it would be to pull it in medially opposed to keep them out laterally- the exact opposite of our goal.

This also means I am pretty sure I just wasted your time, and I am sorry to do so.

[Mark Rippetoe]

If the angle of the femur is going to be changed by a muscle in contraction, what specific joint would that muscle have to cross to do so?

[Subsistence]

If the angle of the femur is going to be changed by a muscle in contraction, what specific joint would that muscle have to cross to do so?

Upon further thought, it should cross the joint between the hip and the femur, not the femur and the knee joint. It would have to function to pull the femur laterally at the hip. Correct?

[Mark Rippetoe]

Correct. So the vastus medialis cannot have any effect on the femoral angle. Knees out comes from the hip. So, your current assessment of the PT gal?

[Subsistence]

Correct. So the vastus medialis cannot have any effect on the femoral angle. Knees out comes from the hip. So, your current assessment of the PT gal?

Seems to clearly be in the wrong here. Will have to ask her what the hell she was talking about.

Thanks for your time.

[Mark Rippetoe]

Sure. See why I did it this way? Now you're prepared to ask her the question.