Running Injury Prevention: Deep Hip External Rotators

Glute training is all the rage right now.  No matter what sport or medical discipline, that seems to be the answer to most things.  I can tell you that the Orthopedic Residency program I am part of is heavily influenced by the work of Dr. Chris Powers on gluteal function in knee and back rehab and performance.  Kaiser Southern California's Kaiser residency has been affectionately referred to by some fellow residents from other parts of the country as "the ass residency" (I am at Casa Colina for my clinical work but do my didactic work at Kaiser).  While yes the gluteal muscles are very important for single limb stability, power production and a variety of other things, one of the important things I have learned from my mentors at Casa Colina is to be careful trying to tie all issues back to single muscle groups.  The body is far more complicated than that and there are many areas dysfunction can come from.

An often overlooked but very important hip muscle group for stability are the deep external rotators.  These muscles are extremely important for stabilization and proper mobility of the hip and pelvis.  Those like Shirley Sahrmann often can be heard arguing for their importance over the glutes for stability and a source for a variety of musculoskeletal issues.  Again refer back to what I said in terms of looking at the larger picture instead of always blaming a single muscle.  However for the moment, let's take a deeper look at these often overlooked muscles.


Image from www.ptonthenet.com

ANATOMY

There are 6 deep lateral rotators of the hip: the piriformis, gemellus superior and inferior, obturatus externus and internus and quadratus femoris. All 6 of these muscles attach from various points on the pelvis to the superior aspects of the femur.

These muscles are innervated by the nerve roots of L4-S2 (for those that hinge heavily at those points, you'd be surprised what some stability there does for nerve function and improving neuromuscular activation of the external rotators.  That's a post for another day).  These are very similar to the nerve roots for the gluteal muscles (which may be important given the shared functions).

Image from CoreWalking

As I have discussed in previous posts, the sciatic nerve (a major nerve to the lower extremity) actually passes either next to or through the piriformis in some people.  Thus while it is important to keep these muscles strong, they must also be appropriately flexible.  A common site of sciatic nerve impingement is at the piriformis (piriformis syndrome).

FUNCTION/BIOMECHANICS

The deep external rotators of the hip are very important stabilizers.  They function to both externally rotate the hip (control femoral internal rotation) as well as controlling pelvic movement especially during the loading response and midstance phases of gait.  You can think of them similar to the rotator cuff of the shoulder.  They stabilize the joint so larger muscles (glute max) can work.  The piriformis is a mild exception to the role as an external rotator as it's moment arm changes as the hip is flexed and becomes an internal rotator at about 60-90 degrees (of hip flexion).

One side has good control, the other does not.   Can you tell which is my stronger side?

Upon foot contact, the deep external rotators along with the glute max resist the internal rotation of the femur to keep the knee in a neutral position.  As the body passes over the contact foot, the external rotators continue to control the normal internal rotation bias of the femur to keep the knee and lower extremity aligned and stable.  Furthermore, they stabilize the pelvis as it rotates forward on the stance leg.

Other muscles that contribute to external rotation include the glute maximus (especially the glute max), the gluteus medius and minimus (when the hip is not flexed), the psoas and sartorius.

Image from Body Works Physio

Given the many connections to various parts of the pelvis, the deep hip rotators also control stability and movement of the sacrum and pelvic floor.  The piriformis has a strong connection to the sacrum and can influence sacral torsion.  The obturator internus has a deep connection to the pelvic floor or levator ani through the arcuate tendon in the pelvic fascia.  So dysfunction in either area is a reason to look at the deep hip rotators.

EXERCISES

Sidelying External Rotation


This is one of the first exercises I introduce to my patients when they present with weakness here.  It is a surprisingly challenging exercise as you MUST keep the pelvis stable while you move the leg.  When this starts to get easy, let your leg drop off a table to work through full ROM from your max internal rotation (strengthen through the range).  Once these are more comfortable, then you can do this with the leg in a neutral position.  Externally rotating the leg at 90 degrees of hip flexion pulls out the influence of the piriformis, which can be good for those with piriformis syndrome or sciatic impingement at that site.

Clamshell


A fairly common exercise that I use for those with difficulty or pain from the above.  Although you will not isolate the deep rotators as much, this allows for the gluteus maximus to kick in more in those patients that are very weak.  Again, do NOT let the pelvis move!  This can (and should) be progressed to monster walks and other weight bearing exercises quickly to get to functional movement once mastered

Banded Rotation

Difficult to show with photos, the pull should be initiated from hip movement.  Holding the arms out straight as shown is more advanced.  Begin with holding them close to the chest.  I am rotating a little too much from my arms in the photo. 

Once the patient reaches decent activation of the hip external rotators, it is time to get back to functional loading.  Since the external rotators work a great deal during foot contact, doing banded rotations is a great way to emphasize them.  Make sure you rotate from the hips and NOT the spine or elsewhere.  Pull from the hips and also NOT the arms.   Other functional weight bearing exercises include monster walks, lateral band walks, single leg pivots and more. 

CONCLUSION

So those are the deep hip external rotators.  Do not forget about them.  They really are the rotator cuff of the hip.  They are extremely important for controlling what happens at the knee, femur, hip, pelvis and sacrum as they influence all of these sites (and more).  So while they are individually small, they each make up a very important group.  Even the piriformis, which is often called a "problem muscle" needs to be strong AND supported by its fellow rotators.  Even those that claim the glutes are everything, I found that those who have difficulty with gluteal activation commonly have weakness in these muscles.  So if you are having glute trouble, you may need to look a little deeper.

Thanks for reading.

As always, my views are my own.  My blog should not and does not serve as a replacement for seeking professional medical care.  I have not evaluated you in person, am not aware of your injury history and personal biomechanics, thus am not responsible for any injury that you may incur from the performance of the above.  I have not prescribed any of the above exercises to you and thus again am not responsible for any injury that may occur from the performance of the above.  This blog is meant for educational purposes only.  If you are currently injured or concerned about an injury, please see your local physical therapist.  However, if you are in the LA area, I am currently taking clients for running evaluations. 

Dr. Matthew Klein, PT, DPT
Casa Colina Orthopedic Resident
Kaiser SoCal Manual Therapy and Sport Fellow 2018

References

Neumann, D. (2012).  Kinesiology of the Musculoskeletal System: Foundations for Rehabilitation - Second Edition.  St. Louis, MI: Mosby Elsevier

Noakes, T. (2003). Lore of Running - Fourth Edition. Champaign, Il: Human Kinetics 

Sahrmann, S. (2002).  Diagnosis and Treatment of Movement Impairment Syndromes.  St. Louis Missouri: Mosby, Inc.

Perry, J. (1992). Gait Analysis: Normal and Pathological Function. Thorafare, NJ: SLACK Incorporated.

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Comments

  1. Hey John.

    Per manual muscle testing and observation, my left side is my stronger side.

    -Dr. Matthew Klein, PT, DPT

    ReplyDelete

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