by Jon Hodges PT, DPT
First things first: How are your headaches? Fixed? Most excellent.
Let’s move on to the rest of your spine. Today I would like to preach to y’all from the pulpit of Johnny Cash — strike that — of Dr. Stuart McGill. Stu (we’re absolutely on a first name basis) is a professor of spine biomechanics at the University of Waterloo in Canada and is arguably the leading authority on spine motion, kinematics and injury prevention. He also has a mustache fit to be bronzed and hung in the Smithsonian. His only detriment is that he mostly references himself, as he has published over 200 articles in the field, so at times it almost feels like he is speaking in the third person — not unlike Smash Williams (miss you, Tim Riggins). Anyway, if you’re a spine dork like me, his book “Low Back Disorders” is an excellent read. Pick it up.
Now, where were we? Oh yeah, I’m trying to save your spines from the fire and brimstone of terrible disc herniation hell. Let’s start with some basic anatomy. The intervertebral discs are the primary shock absorbers of your spine and are, in an over simplistic description, not unlike a large radial tire filled with jelly. These discs are flexible and exceptionally resilient, but even so, disc injuries are probably the most common complaint we see at Nevada Physical Therapy in regards to low back pain. Although typically not seen until a person’s mid 20s or later, McGill argues that delamination (the breakdown of the tough tire-like exterior) may begin far earlier. With the recent resurgence of deadlifting in the gym and Crossfit’s penchant for deep squats, please believe I am seeing some serious future low back pain developing due to improper training. Calm down, I’m not talking about all of you, but as the weeks progress, many of you will hopefully make the necessary adjustments to save your spines now rather than later.
Back to the discs: When you flex, or round your spine, the disc material is pushed posteriorly (towards your back) and when you extend or arch it is pushed anteriorly (or towards your belly button). These movements in and of themselves are normal. The problem is, we spend so much time in flexion that the disc material almost always herniates posteriorly.
Think about it this way: If you take a s’more and bite the two ends of the graham cracker, the marshmallow finds the path of least resistance, usually away from the impending force (your teeth) and “herniates” the opposite direction (usually onto your lap). The spine works the same way. When we repeatedly flex forward, the disc material may eventually herniate posteriorly and, in some cases, smush your nerves. You see this most often in athletes performing deadlifts with a rounded spine or just poor form lifting something heavy and awkward (whisper voice: kegs).
McGill shows, in the lab using a pig spine (gross), that repeatedly transitioning from extension to flexion (a perfect example being sit-ups) will eventually disintegrate your discs. This is bad. What is worse, according to McGill, is the prolonged static flexion we subject our discs to with activities such as sitting. Further, initiating athletic movements after prolonged sitting is an excellent mechanism for disc dysfunction as the discs are often stiff and not very flexible for a short while. So, sitting in a three-hour class and then running to Lombardi to do deep overhead squats? No bueno. But what does it all mean?
Here’s the moral of the story. When you are sitting in class, try to maintain a neutral spine. Not overly extended, not lazily stooped into flexion. Stay upright. If you’ve been sitting for a long period of time and are going to be training shortly thereafter, take it slow and work on some extension (up-dog, cobra, cat-dog, etc. for my yogi brethren). When performing weighted movements requiring deep trunk flexion like deadlifting, squatting, snatches, etc., make sure you don’t transition from extension to flexion at the bottom position (Google: butt wink).
In summary, let’s all stop performing sit-ups. I’m going to cover these last points separately in detail in the coming weeks, but I’m going to just need to ask for some faith here. Sit-ups are bad for your back. If you round your back with any weighted movements, you are asking for trouble. If you sit with poor posture, you are slowly ruining your discs. Now I’ve seen dudes deadlift 600 pounds with a rounded back no problem. I know people that have sat at desks with awful posture 10 hours a day for 20 years with not so much as a hint of disc disease. I’ve even seen the guy who does 500 sit-ups a day his whole life with never so much as a twinge.
They are the minority.
Know your spinal alignment, train safe, sit happy and we’ll fix your deadlift next week. You have now been baptized in the holy waters of Dr. Stuart McGill. Go forth and spread the good news.
Jon Hodges PT, DPT is a physical therapist at Nevada Physical Therapy on campus. He can be reached at firstname.lastname@example.org.