Sports Medicine Research: In the Lab & In the Field: Guest Post: The Back Side of Knee Pain (Sports Med Res)


Friday, June 10, 2011

Guest Post: The Back Side of Knee Pain

Gluteal Muscle Activation during running in females with and without patellofemoral pain syndrome

Willson JD, Kernozek TW, Arndt RL, Reznichek DA, Scott Straker J. Clin Biomech (Bristol, Avon). 2011 Mar 7. [Epub ahead of print]

Running is one of the most common activities. If it’s not running as a sport itself, people are running to prepare for their sport or maybe even just to stay in shape. One of the common overuse injuries that occurs in runners is patellofemoral pain syndrome (PFPS). Many studies have investigated PFPS and have shown that females are two times more likely to develop it than men. In addition, decreased hip strength is one of the most consistent published finding associated with PFPS. The purpose of this study was to examine the magnitude and timing of gluteus medius (GMED) and gluteus maximus (GMAX) muscle activities among females with and without PFPS during running. The authors gathered a group of 20 females with PF pain and a group of 20 females without any knee pain. All participants were evaluated with 3D running kinematics, kinetics, and GMED and GMAX EMG (electromyography). They found that females with patellofemoral pain demonstrated a delayed and shorter GMED activation compared to the females without knee pain during the stance phase of running. They also found greater hip adduction and internal rotation joint excursion (range of motion) which was also correlated with later GMED and GMAX EMG activity in the PFPS group.

This study is important to support and identify several biomechanical and neuromuscular dysfunctions at the hip in patients experiencing PFPS. The main finding showed that patients with PFPS have a delayed muscle activation of the GMED. They also showed that these patients had greater amounts of hip adduction and internal rotation joint excursion than those without knee pain. These are interesting findings that have been theorized for several years. Although these findings establish associations between biomechanical and neuromuscular dysfunctions and PFPS, they cannot decipher whether these findings are the causes of PFPS or the result of the pain associated with PFPS. The EMG results correlating with the biomechanics suggest that the dysfunction of the GMED lead to positioning the femur in adduction and internal rotation. This position, over time, will lead to discomfort by causing the patella to track laterally during running. This laterally tracking patella outside the femoral groove will cause a repetitively large compression force to the patellar articular cartilage. By addressing these deficiencies in the hip, the femur can be properly repositioned during the stance phase to improve the efficiency of patellar tracking alleviating the repetitively large compression forces. This ultimately can lead to resolution of the individual’s pain. What are your thoughts on this concept of realigning the patella by correcting the position of the femur instead of realigning the patella with use of tape, bracing, or VMO exercises?

Written by: Tommy Nowakowski Jr.
Reviewed by: Stephen Thomas


John said...

First off I would like to say that I really enjoy reading all of these posts. They have been very thought provoking and helpful for a new clinician in the field such as myself.
Although I am a 'rookie' in the PT field as I have only been a treating clinician for a little over a year now, I feel like PFPS is something I see a lot of. It is very interesting to see how many of these patients do present with fairly significant hip abd weakness to MMT. I think in reference to the last question raised in the post, the question should be which techniques we should use in 'conjunction with' rather than 'instead of' another. Because strengthening muscles, such as the Glute Med/Max, is not an overnight process, other modalities and techniques should be used as well to initiate more immediate relief.
Within the past few months, I have been exposed to Kinesio taping techniques (in this case for the quad and VMO) and have observed a pretty dramatic pain relieving effect with its application. I like using this taping technique now more than the McConnell medial glide technique because it is less restricting and seemingly works more to facilitate the muscle firing pattern.
By addressing all of these issues, you will have a happy client because they can feel the effects immediately and 'buy into' your program, which will allow you to continue treating the muscles imbalances and the longer term components as well.
Thank you again for all the posts.
-John B

Tom Nowakowski said...


Thanks for the comments! No question you must provide these individuals with some type of immediate relieve or else you can have the greatest gameplan in the world and you will never be able to implement it. My question as you pointed out states "instead of" because I feel far too many clinicians are using the kinesiotape, VMO strengthening exclusively and not attacking the way the femur is positioned. Just as you said the abductors can't strengthen overnight, neither can the VMO. The kinesiotape (which I also use) undoubtly gets results, however, its just a band-aid solution. I'm not sure how you are kinesiotaping but give the kinesiotape a shot with assisting medial glide as well. I have found it to be much more effective than the McConnells tape.

Keep the comments coming. Thanks again!

Tom Martin said...

Nice Post Tommy
With this patient/athletic population, my initial focus is with hip (and core) strength.
The literature has definitely supported this treatment approach based on previous posts.
In regards to John's "overnight" comment, the previous post which looked at Glut med strength increases over a 3 week period from just performing 2 exercises helps to show that changes can occur in a short period of time.

I must admit that when the conversation comes to KT versus McConnell, my views are complicated.

I favor McC taping over KT. I will usually try it when a patient/athlete has a hypermobilie patella versus hypomobile (favoring medial glide). My thought process is the tape will better support a hypermobilie patella than combat tight lateral retinacular issues. My results are mixed.
KT is something which intrigues me from the standpoint that I have had fellow clinicians report the same initial improvements from techniques viewed off You Tube, with no other training. Which can probably be said for McC taping also.

Great post and comments.

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