Monday, July 10, 2017

Is There A Secret Sauce? - Part VI

Gradients of Gluteus Medius Weakness – Part III
In our last couple of blogs, we have talked about the function of the gluteus medius in both an open kinetic chain and closed kinetic chain.  We have also talked about how this muscle functions on both the femur and the hip and how weakness of this muscle will present itself at the femur versus at the hip.  Although most understand the movement that occurs at the femur, identifying weakness that is represented at the hip is just as critical as it is at the femur.  With the shear stresses that are imparted to the labrum of the hip during these motions, hip motion can have just as devastating effect on the hip as the movement can have on the ACL at the knee. 

So now that we have identified it, how do we strengthen it?  Easiest thing is to look at the function of the muscle.  Before we get into specific exercises, let’s say one obvious thing, if you are going to strengthen this muscle, do it right!  Every single day, we see physical therapists, athletic trainers and personal trainers who do these exercises wrong and just strengthen bad or compensatory movement patterns.  In these cases, it is better to not do it than to do it.  Because strengthening bad movement patterns sets them up for greater risk.  To increase recruitment or maximal volitional contraction (MVC) of the gluteus medius, we need to think of it not just as strengthening the muscle.  You have to change recruitment patterns and sequence of firing.  Yes strength is a part of that but only a part.  To change MVC during functional movement you must change motor plans in the primary motor cortex. 

In 1998, Karni et al showed that in order to change a motor plan in the primary motor cortex (PMC), it required 3,000 to 30,000 repetitions.  The authors also showed that you can employ techniques which result in quicker change and that there are also things that we do that will result in slower changes.  From this, we have developed a saying.

Poor Technique = Poor Motor Learning = Poor Performance

Learn it, live it and teach it.  Change in the PMC is critical to change how the muscle fires during movement.  Based on the science, we know for every repetition that you do incorrectly, you then must do three reps to have a positive change on the PMC.  Considering this then, you must do one rep to offset the bad movement, one rep to offset the previous bad rep and one rep to drive a positive change in the PMC.  Sounds simple enough right?  Sadly, even with highly educated individuals, we typically see athletes doing the exercise incorrectly under direct supervision.  We then wonder why their movement has not improved that even when we are focusing on the right area and muscles.  Identifying the previously mentioned movements is hard enough when doing it in an assessment let alone when we are doing exercises.   There are numerous exercises to strengthen the gluteus medius in both an open kinetic chain and closed kinetic chain.  Therefore, we will only cover two exercises in depth which work on the gluteus medius in a closed kinetic chain. 

One such exercise, we call the lumbopelvic disassociation (LPD).  You can view a video of this on our YouTube channel, by clicking here.  This exercise is intended to do several things:

·        Assist athletes in discerning lumbar motion from hip motion by improving proprioception through the hip
·        Provide a closed kinetic chain exercise to start strengthening the gluteus medius

The video is intended to give viewers some pointers.  Although the athlete may do it incorrectly, this video’s intent is to not only show the exercise but to show where people go wrong.  This said, there are some common mistakes that people make in performing this exercise and which we can look for during performance of.  Once you have viewed the video, take a look at the athlete in this photo performing the exercise, you see several key factors. 

·        Stance knee is slightly flexed – most want to hyperextend to create stability
·        Knee/ankle/foot are stable
·        Non-stance leg is extended – this places the lumbar spine in extension and aids athlete in keeping neutral spine and not going into lumbar flexion during. 
·        Chest is up – promotes thoracic extension which also promoted lumber extension
·        Hips are level

If you compare the above athlete to the athlete pictured in the next photo, you can see some slight variations that also lead to strengthening compensatory strategies.  Keep in mind, this athlete is demonstrating minor deviations and is not even close to the magnitude of deviations that you would typically see when someone does this incorrectly.  We use this example because it is even these slight changes that result in significant impacts to the MVC of the gluteus medius.  In this case what we see is:

·        Non-stance leg in extension and chest up – good
·        Neutral spine position – good
·        Retrotrendelenburg position of the right hip – indicated with the yellow circle and seen with the hips not being level and the left hip coming up (placing the right hip in a retrotrendelenburg position)
·        Externally rotated position of the right foot – indicated with the red circle

The combination of the raising of the left hip and the external rotation at the right foot makes the retrotrendelenburg much greater at the right hip.  If we allowed him to continue this with all of his training, we can anticipate that when he performs in single leg stance or single limb tests, that his natural tendency is going to go into a retrotrendelenburg on the right when performing single limb tests on the right.  The simple correction is having him bring his right foot in slightly and drop his left hip down slightly. 

What is pictured above is a retrotrendelenburg but keep in mind that this can also present itself as a trendelenburg.  Easiest way to see both of these is to simply look at the hip position.  Are the hips level during the course of this exercise?  You have to watch closely during the beginning phases of this exercise as it may present itself here as the athlete rotating their hips out.  If they do and we allow them to continue that, then we are again just reinforcing the bad movement patterns and strengthening their compensatory strategies. 

Another common exercise used to strengthen the gluteus medius in a closed kinetic chain is side-stepping with a theraband.  In this video, we again go through some specific pointers related to the technique and compensations.  Even though this is one of the most widely used exercises for gluteus medius weakness, it is also one that is often performed incorrectly a majority of time. 

Some of the most common mistakes seen during this exercise are pictured here:
·        Having the band to high – higher the band is, the easier the exercise is.  Placing the band at the ankles not only makes the exercise more difficult but also brings in higher recruitment along the lower kinetic chain.
·        Band too loose – if the band is not tight at the starting position, it will be too easy throughout the motion and only stress the muscle at its weakest point in the length tension curve.
·        Lack of core activation – keeping in mind the concept of specificity, if we train with increase in lumbar lordosis (lack core activation) throughout this exercise then this promotes lack of core activation when it matters the most.
·        Allowing compensation during performance of the exercise.  Common compensations are:
o   Externally rotating with stepping out – this allows increased recruitment of the hip flexors and reduces MVC of the gluteus medius
o   Standing when bringing feet together – this is a much easier position for the movement and maintaining this position throughout will aid in increased MVC.  

Taking these few pointers and applying to your gluteus medius strengthening will not only make a huge difference in what the athlete feels but also aid in improving their mechanics with CKC movement.  We hope that you found this blog insightful and useful.  As we stated previously, stay tuned and if you like what you see, SHARE THE PASSION!  It is the biggest compliment you can give.  Follow us on Twitter @ACL_prevention and tweet about it.  #ACLPlayItSafe and help us spread the passion.

Dr. Nessler is a practicing physical therapist with over 20 years sports medicine clinical experience and a nationally recognized expert in the area of athletic movement assessment.  He is the developer of an athletic biomechanical analysis, is an author of a college textbook on this subject  and has performed >5000 athletic movement assessments.  He serves as the National Director of Sports Medicine Innovation for Select Medical, is Chairman of Medical Services for the International Obstacle Racing Federation and associate editor of the International Journal of Athletic Therapy and Training.