I have written about Patella Femoral Pain Syndrome before, but I want to re-address the condition here, due to some really cool new insights. This is a brief video (2 min 51 sec) that will help you visualise the problem –
The moment the knee cap strays out of the ‘valley’ that it is designed to travel through, we get runners knee. Internal rotation of the tibia due to excessive pronation or the collapse of the foot arch will bring this about.
A weak glute medius will also cause your knee to fall inwards as your body moves over your center of gravity, also contributing to the PFPS or patella femoral pain syndrome.
There is another factor when it comes to looking at PFPS, and that is an imbalance between the relative strengths of two of the four quadriceps muscles, the vastus lateralis oblique and vastus medialis oblique. Don’t tune out here, I will do my best to break this down into an understandable concept.
Let’s get into some Latin first: (Read each table down)
|Vastus||Big (muscle)||Vastus||Big (muscle)|
|Lateralis||On the outside||Medialis||On the inside|
|Oblique||That pulls at an angle||Oblique||That pulls at an angle|
Here is a breakdown of the various sizes of the four quads –
|Vastus Lateralis||674 cm cubed|
|Vastus Intermedius||580 cm cubed|
|Vastus Medialis||461 cm cubed|
|Rectus Femoris||339 cm cubed|
The vastus lateralis muscle pulls at an angle of between 12 to 15 degrees, and the vastus medialis at an angle of 55 degrees, when measured against the femur. If everything is balanced out, the knee cap moves up and down the femoral head and we have a happy runner/cyclist/lunge specialist.
However, the lateralis muscle often becomes overactive while the medialis gets progressively lazier. It’s as if the medialis looks across to check if the other three quad muscles are working, and if it sees them active, decides to take things easy. (Much like a road crew, one person digs, while five others stare down the hole as if something far greater was taking place).
What to do if you have an overactive lateralis muscle and an underactive medial muscle?
Here comes the fascinating part:
There are ways of strengthening the medialis muscle. Any leg extension that focuses on the last 15 degrees of movement or so should help- I often advise people to do a variation of that while doing our Runner’s Leg Assessments. (I have a nifty way of doing that if you don’t have a gym contract).
However, research reports that there is also a way of lessening the pull of vastus lateralis, thereby balancing the two muscles out, and getting your knee cap to track more evenly over the femoral head.
What interests me, is that this is where acupuncture meets with running dynamics.
A paper came out detailing a single acupuncture point, stomach 34, located on the vastus lateralis, that normalizes the function of the muscle. This means that the muscle no longer over pulls as opposed to the vastus medialis, and therefore allows the knee cap to move more correctly in its groove. Small but definite imporovements have been noted with regard to velocity, cadence and stride length.
The point, stomach 34, is located above the lateral border of the knee cap.
According to the study, one treatment or needling had a positive effect. The more you treat, the better. This needs to be done in context of the other factors: shoes, vmo strength, gait modification etc.
Give me a call if I can help. One wants to tackle the injury holistically.
Souza DR, Gross MT. “Comparison of vastus medialis obliquus: vastus lateralis muscle integrated electromyographic ratios between healthy subjects and patients with patellofemoral pain.” Phys Ther. 1991 Apr;71(4):310-6. Web. 25 Nov 2012.
Cowan SM, Bennell KL, Crossley KM, Hodges PW, McConnell J. “Physical therapy alters recruitment of the vasti in patellofemoral pain syndrome.” Med Sci Sports Exerc. 2002 Dec;34(12):1879-85. Web. 26 Nov 2012.
Hauer K, Wendt I, Schwenk M, Rohr C, Oster P, Greten J. Stimulation of acupoint ST-34 acutely improves gait performance in geriatric patients during rehabilitation: A randomized controlled trial. Arch Phys Med Rehabil.2011 Jan;92(1):7-14. doi: 10.1016/j.apmr.2010.09.023.