Low back pain is very common. In the US alone, various sources have cited the incidence going up to 80 % (Seay, Emmerick, Hamill, 2011). This does not exclude runners and athletes as back pain is one of the more common injuries I treat among the athletic population. There is no overarching source of back pain as many experts will tell you. It is usually unique in someway to the biomechanics of the individual. Many of the patients I see with pain in this area generally have an imbalance between a few muscle groups. One of the more commonly talked about imbalances is between the glutes and the lumbar muscles. Glutes are the big fitness craze right now, so let's actually discuss the biomechanics on why you need to balance these two muscle groups out.
Image from www.aerialibrium.com
ANATOMY AND KINESIOLOGY
Per the photo above, the lumbar (low back) muscles and gluteal muscles have a common connection: the pelvis. Specifically they both insert onto the posterior section of the pelvis and lumbosacral fascia. They both strongly influence the pelvis depending on singular or coordinated contractions. I am only going to discuss sagittal plane motion in this post as the pelvis, lumbar muscles and gluteal muscles are very complicated, affecting all planes of motion. I will discuss the others in future posts.
The hip extensors not only extend the hip but also posteriorly tilt the pelvis. The lumbar muscles, also commonly called the back extensors, both extend the trunk and anteriorly tilt the pelvis. Given that both groups extend, they function as synergists to create lumbo-pelvic extension. They have opposing actions when it comes to pelvic tilt. Together when balanced together they stabilize the pelvis (along with the abdominals) in the sagittal plane and allow for a stable base for hip extension to occur and power you forward during the propulsive phase of running.
The pelvis tends function best when it is stabilized in a fairly neutral position (between anterior and posterior rotation. However, most people tend to hang out in an anterior pelvic tilt for a couple reasons. Some tend to overutilize their lumbar muscles to compensate and create hip extension in a world that sits too much and has tight (or commonly tight and weak) hip flexors. Others use their lumbar muscles excessively for trunk stability, which also pulls the pelvis anteriorly as the trunk is held upright. Others may have weak hip extensors and instead of using their hips to absorb the shock of landing instead have to use their back muscles as that is the next muscle group up the kinematic chain. There are many other muscles that balance this out, including the abdominals also attempting to counteract the strong pull of the lumbar musculature into an anterior pelvic tilt. One of the more important muscle groups are the hip extensors for the reasons I mentioned above.
Image from www.jordanhasay.com Notice the lumbar extension with hip extension
From a shock absorption standpoint the hip extensors are very important in protecting the low back. If the hip extensors are weak, the lumbar muscles have less force opposing them and the pelvis will tilt anteriorly. As the pelvis tilts anteriorly, the low back will extend. Rather than keeping the low back in a fairly neutral position (where it does best), you now have it extending considerably with every stride. When lumbar spine goes into a great deal of extension, the facet joints (sides of the vertebrae) lock the joints and prevent any extra movement. A lack of movement in joints means that instead of allowing some movement and muscular shock absorption, the joints and passive structures absorb more force. This puts a great deal of pressure at the low back, which is compounded by possible weakness in the hip extensors. This is not to say that lumbar extension is bad. Rather a mild amount is normal given the typical mild lordosis of the lumbar spine. An excessive amount of lumbar extension or flexion is not so great when being loaded heavily during repetitive activity (some exceptions do arise with various degenerative conditions of the spine).
Image from runnerclick.com
When the hip extensors are weak, not only do they not help balance the low back and pelvis, but now the shock from each footstrike no longer is absorbed as well at the hip. Thus it will continue to travel into the low back where is must be dealt with (as mentioned earlier). Some force attentuation at the low back is normal. A great deal is not. This is one of the many reasons (there are many more than this) why the most common points of osteoathritis in the spine are at L4-L5, L5-S1 (the lowest portion of the lumbar spine). So is it a surprise that this could contribute to low back pain?
So you need to get your butt muscles and hip extensors working! They not only create a great deal of the power during the propulsive phase of running that pushes you forward, that are also important for balancing out the powerful pull from your lumbar extensors!.
EXERCISES
Gluteal Isometrics (Butt Squeezes, Clam Isometrics)
Clamshells: 5-10 second holds for activation, repetitions for strength/endurance (low rep high weight for strength, high rep low weight for endurance).
A great way to start out if your butt is weak! All you need to do is start by lying on your back, then squeeze your butt cheeks!! It seems simple, but those with severe weakness will have a hard time with this! The point of this exercise is to improve the brain's ability to access those muscles. I have been taught two ways. One is just lying on your back trying to squeeze your rear end. The other is performing a clam with a band but holding at the top for 30-60 seconds. Regardless of what you should do, the holds should be AT LEAST 5-10 seconds (up to 30 to 60 seconds) and you should feel your butt muscles and nothing else working.
Heel Bridge
Traditional bridge with toes help. Helps with gluteal facilitation. This can also be done in the hip thrust position for increased difficulty.
The Heel Bridge is a variation of the normal bridge that I have found helps patients with gluteal activation. Perform a normal bridge, making sure to hinge from the hips and not the back (put your hands on your hips to help guide this motion). Lift your toes up throughout the motion. You will be surprised how much more your butt muscles turn on!
Chair of Death
The Chair of Death Exercise: To improve hip hinge and hip biased movement.
A favorite of mine that I picked up from Jay Dicharry (check out his book Anatomy for Runners). This is a great exercise to teach people how to hinge from the hips correctly. People will move from the places with greatest mobility. Often times that is the low back. Using a rod to help provide feedback on keeping the back neutral and trunk controlled will help teach people how to hinge from the hips. This should not be a giant, fast, motion. Initially these should be performed with great mindfulness about where you are trying to move from (the hips). I typically have people do this for time rather than reps to keep them focused on what they are doing, not how many.
CONCLUSION:
I do not want to suggest that the lumbar extensors are not important. There are plenty of people with weak or overstretched lumbar extensors (which I also see). The case I am trying to make above is one of the many reasons why your butt muscles should be strong. This however should be kept in perspective with the larger picture of muscle group function. No one muscle group will can completely prevent injuries, make you a professional athlete or give you great power/endurance/strength. One of the more important things I have learned in my orthopedic residency is that you need to look at everything and not just assume what is going on. Low back pain can come from muscle imbalances, chronic postures, referred pain, poor movement patterns and far more. The above is just one possibility for us to look at in the complex system of human movement and function.
Thanks for reading.
Editor's Note: Back Pain is very complicated and rarely comes from one source. In the future I will also discuss the musculature affecting the sacrum, pelvic rotation in the transverse plane and more that CAN contribute to back pain during running.
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
References
Sahrmann, S. (2002). Diagnosis and Treatment of Movement Impairment Syndromes. St. Louis Missouri: Mosby, Inc.
Noakes, T. (2003). Lore of Running - Fourth Edition. Champaign, Il: Human Kinetics
Perry, J. (1992). Gait Analysis: Normal and Pathological Function. Thorafare, NJ: SLACK Incorporated.
Seay, J., Emmerik, R., Hamill J. (2011). Influence of Low Back Pain Status on Pelvis-Trunk Coordination During Walking and Running. Spine, 36(16): 1070-1079. DOI: 10.1097/BRS.0b013e3182015f7c
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