The Hip External Rotation Clamshell Exercise

clamshell exercise

A few weeks ago I published an article on what I thought were two essential exercises that we should include in every program, which included the shoulder W exercise and the hip external rotation clamshell exercise.  After that post I received a lot of emails asking for a video of the shoulder W exercise, so I wrote up another technique article dedicated solely to the shoulder W exercise.  Well, in response to that post, I have received a bunch more emails asking for a similar video on the hip clamshell exercise.  So here is my video demonstration of my technique, as well as a variation of performing the clamshell exercise in neutral rotation.


Why I Like the Hip External Rotation Clamshell Exercise

I want to again reiterate that there are a lot of exercises for hip external rotation that I use everyday, but I highlighted the clamshell exercise for it’s simplicity and effectiveness.

I have talked in the past about the importance of strengthening the gluteus medius and some of the dysfunction that can occur with poor coronal plane strength.  We really are a sagittal plane society and this has a large impact on many of our dysfunctional movement patterns, so strengthening muscles that externally rotate the hip is important.  If this isn’t something you’ve been emphasizing, go back and read some of the above links.


Hip Clamshell Exercise in Hip Flexion

EMG studies have shown that the clamshell produces a good amount of gluteus medius and gluteus maximus activity, especially if technique is excellent.  Notice in the video below that I really emphasize placing your hand along your iliac crest.  This helps to cue to body to not rotate and incorporate the low back, which is likely the most common fault during this exercise, especially in those that have really weak glutes.  Also, by placing your hand on your hip like this, you can put your thumb on your glutes to feel and facilitate the contraction.  It really helps with your technique.

It should also be noted that the contralateral leg, the one of the bottom, has to isometrically stabilize into hip ER, to prevent the band from pulling the bottom leg up, so again, just another reason why I like the clamshell exercise.


Hip Clamshells in the Neutral Position

While performing the clamshell exercise for hip external rotation has been shown to produce similar amounts of gluteus medius EMG activity in the 30 degree and 60 degree positions of hip flexion, I also like to perform the exercise with hip flexion at 0 degrees, or neutral.  The majority of us already have overactive hip flexors, so anytime I can work the hip muscles outside of the hip flexed position is good.  It is also well documented that the posterior moment arm of the gluteus medius is decreased while the hip is flexed, making the glute medius less effective in externally rotating in this position.  Hip ER in a flexed position likely increases the contribution of the gluteus maximus and deep external rotators.

In the video below, I demonstrate the hip clamshell exercise in neutral, or 0 degrees of hip flexion.  The first thing you’ll notice is that my range of motion is less.  This is normal and not indicative to poor performance in this position.  Normal range of motion for hip ER is about 30 degrees with the hip extended and 50 degrees with the hip flexed. You will notice that people with weak glutes will not like this exercise as much because it is more difficult!  Even more reason to be using it.



What do you think?  Have you performed any variations of the clamshell exercise that you feel are essential?  I know there are many more tips and alternative exercises, but I hope these videos clarify some of my thoughts when discussing strengthening the gluteus medius by performing hip external rotation with the clamshell exercise.

The Best Exercises for the Gluteus Maximus and Gluteus Medius

In a past article, I discussed assessing and treating dysfunction of the gluteus medius.  I reviewed an article from the Journal of Strength and Conditioning Research and the author’s recommendations.  Taking this information one step further, a recent article in JOSPT has quantified electromyographic activity of the gluteus maximus and gluteus medius during common exercises.  This information is helpful when deciding which exercises to perform in your patients or clients.

Based on the results of this study, we can identify exercises that produce the highest amount of EMG activity.

Gluteus Medius

  • imageSide-lying hip abduction – 81%
  • Single limb squat – 64%
  • Lateral band walk – 61%
  • Single-limb deadlift – 58%

image  image  image

Gluteus Maximus

  • Single-limb squat – 59%
  • Single-limb deadlift – 59%
  • Sideways, front, and transverse lunges – 41-49%

In addition to the manuscript, there are good video demonstrations of the exercises and a PowerPoint presentation available at the JOSPT website.  When I accessed this, I believe they were all available for free.

Clinical Implications

Based on the results of this article, here are a few things that came to my mind

  • Side-lying hip abduction should be used in all people needing glut medius strengthening.  EMG activity was almost 20% higher than the next exercise.
  • The single limb squat and single-limb deadlift exercises activated high amounts of EMG activity for both muscles
  • image The clam exercises produced EMG activity between 34-40% for both muscles.  While this is low in comparison to other exercises, the authors did not use resistance during testing.  I would still use this, especially with a resistance band around the thighs, as am early-stage or activation exercise. The authors also compared clams at 30 degrees and 60 degrees of knee flexion and showed no different in gluteus medius activity.
  • The lunge exercises produce a moderate amount of EMG activity and are likely good early-stage exercises to progress to prior to the single-leg squat and deadlift exercises

DiStefano, L. (2009). Gluteal Muscle Activation During Common Therapeutic Exercises Journal of Orthopaedic and Sports Physical Therapy DOI: 10.2519/jospt.2009.2796

Assessing and Treating Dysfunction of the Gluteus Medius

The October 2008 issue of the Journal of Strength and Conditioning has an impressive review article of the anatomy, function, assessment, and strengthening of the gluteus medius from a group of clinicians in New Zealand.  The authors do a good job reviewing some of the basic anatomy and function of the muscle and relating this information to research reports looking at dysfunction and treatment of the muscle for several lower extremity injuries.

I think this is a great topic of discussion as the role of the gluteus medius in normal function and rehabilitation has been receiving attention lately as attention is being paid to strengthening and training the body in the frontal plane of motion and out of the sagittal plane.

gluteus medius

The Role of the Gluteus Medius

When you really break down the function of the gluteus medius, you see that it is far more valuable as a pelvis and lower extremity dynamic stabilizer than it is a pure hip abductor.  This is apparent when looking at the mechanism of a Trendelenburg Gait.  The role of the gluteus medius during activities such as walking and running is to dynamically stabilize the pelvis in a neutral position during single leg stance.  As you can see in the photo below, weakness of the right gluteus medius will cause the left hip to drop when standing on the right limb.  Conversely, athletic patients are often masters of compensation and may be able to keep the pelvis in neutral while the lower leg will adduct and internally rotate.

weak gluteus medius

In addition, the role of the gluteus medius as an external rotator of the hip when the hip is in a position of flexion is also important to consider.  These factors together are likely why dysfunction of this muscle is commonly found in several pathologies, such as iliotibial band, patellofemoral injuries, ACL, and ankle injuries.

Assessment of the Gluteus Medius

The authors describe several methods of evaluating the gluteus medius.  These include:

  • Standard manual muscle testing of hip abduction in sidelying.  Because the gluteus medius also has an effect on other hip motions, I often recommend a full testing of hip flexion, abduction, ER, IR, and extension as well.
  • Double- to single-leg stance test.  Simply a test such as the photo above.  The patient is instructed to stand on one limb and pelvis orientation is documented.
  • The authors also recommend adding an upper body movement to the single-leg stance test. This will further challenge the patient, specifically the athletic patient.  During this, the patient is instructed to balance on one limb while reaching the arms overhead and leaning away from the stance leg.  This will move the patient’s center of gravity further away from the stance limb and require a greater amount of gluteus medius stabilization to avoid the dropped pelvis position.
  • In addition to the above described, I would also recommend that patients should be observed during several functional activities, especially if a specific activity tends to exacerbate symptoms.  This could include eccentric step-downs, front lunges, or even running and jumping activities for athletes.  Watching the kinematics of the pelvis and lower body closely can be very beneficial.  Personally, I often try to video tape these movements as well.  For my athletes I have sophisticated camera systems but I also travel with a simple flip cam that I plug in to my laptop and quickly record and view back with my patients.  I actually do not like the actual Flip cams, the angle of the lens is terrible.  I actually use and really love the Creative Vadocheck it out on Amazon.  In addition to having a better wide angle lens, I can control the video quality.  It is inexpensive, small, portable, plugs into my computer for charging, and shots great video.  In just a few minutes I have a great quality video to watch with my patients.  I try to take it a step further a draw on my videos and photos as well.

trendelenburg during step down

Treating the Gluteus Medius

While the beginning of the paper provides a brief, yet basic, review of the normal anatomy, function, and potential for injury implications of gluteus medius weakness, the strength of the paper lies in the later half that reviews the evidence behind some exercises designed to strengthen the gluteus medius.

The authors provide a thorough table that lists the many exercises described for gluteus medius strengthening.  Most of these are basic recommendations, such as sidelying hip abduction straight leg raises and standing hip abduction.  However, the authors combine the work and recommendations of three articles to develop a gradually progressive exercise program.

The progression is designed to gradually enhance motor control, endurance, and strength.  The program is broken down into three phases:

  • Phase I: Nonweightbearing and basic weightbearing exercises such as clam shell exercises, sidelying hip abduction, standing hip abduction, and basic single leg balance exercises. Criteria to progress to stage II is that the patient can hold their pelvis level during single leg stance for 30 seconds.
  • Phase II: The second stage progresses the weight-bearing exercises and gradually progresses stability exercises by (a) translating the center of gravity horizontally via stepping and/or hopping exercises; (b) reducing the width of the base of support, (c) increasing the height of the center of gravity by elevating the arms and/or hand-held weights, or (d) performing the exercises on unstable surfaces.
  • Phase III: The third stage is used for athletes and designed to prepare them for function, sport-specific movement patterns.

I agree with this progression but think that the authors are missing one key point regarding training of the gluteus medius.  Because it is such a valuable component of dynamic pelvis and lower extremity stability.  I also would encourage clinicians to also incorporate exercises designed to promote hip stability during normal sagittal plane movements such as squatting.  To do this, I often just simply incorporate a piece of exercise tubing around the distal thigh (just higher than the knee) of the patient during exercises such as mini-squats, wall squats, and leg press.  The patient is instructed to isometrically set the hips in a neutral position while performing the exercise.  Cueing is often needed at first to be sure that the patient does not let their hips drip into adduction and internal rotation.  I have found great success in this type of exercise as it required the hips to dynamically stabilize against a hip adduction/internal rotation moment during common functional activities.

band around knee leg press

There is also a section that reviews some of the available evidence behind choosing sets, repetitions, frequency and duration of rehabilitation programs.  Overall, a great review of some of the basics regarding the gluteus medius and definitely a great starting point to develop a comprehensive rehabilitation or injury prevention program.

Check out my other post on an article reviewing more great information on gluteus medius exercises and gluteus maximus exercises.

Presswood L, Cronin J, Keogh J, Whatman C (2008). Gluteus Medius: Applied Anatomy, Dysfunction, Assessment, and Progressive Strengthening. Strength and Conditioning Journal, 30 (5), 41-53

Images from: Prevent Disease, UWO

Want to learn more about how to get the most out of the hips and glutes?  I have two great inner circle webinars on My Top 5 Tweaks to Enhance Hip Exercises and How Pelvic Position Influences Lower Extremity Stretching.  Click here to learn more about my Inner Circle and how you can gain access to these webinars and more for only $5.

Mike Reinold Inner Circle logo in monitor