Rethinking Thoracic Spine Mobility

This past summer, I read Sue Falsone’s Bridging the Gap from Rehab to Performance and it was a fantastic read. I have some previously established strong feelings about the importance and value of what Falsone calls the Performance Training Continuum, so I was obviously excited when I discovered this book. Among the numerous pearls I found throughout was a section on thoracic spine mobility that really got me thinking about the way we train upper back ‘flexibility’ in circus.

Spoiler alert: Anatomy Geekery ahead.

In order to make sense of the practical stuff to follow, we’re going to need to go over some anatomy.

This is a side view. The left side is the front of the body; the right side shows your back. Not shown, but kind of  important, are your lungs.
They kind of fill up much of the space there.

As you can see, this is a view of your ribcage and its contents. The space inside, is known as the mediastinum. It is the space on the other side of your ribs and is bordered on the inside by the pleurae (the sacs that contain the lungs). The mediastinum thus contains your heart and its associated blood vessels, your esophagus and trachea, along with other fun stuff like lymph nodes. There are also some fairly significant nerves that run through the mediastinum.

It is the “nerves” bit that is our focus today. Specifically, in the posterior mediastinum there is a nerve called the sympathetic trunk. It runs on either side of your spinal column, from your first thoracic vertebrae down to about your second lumbar vertebrae. As the name implies, it might be best to think of it not so much an individual nerve as the trunk nerve from which many smaller nerves sprout and go off into the body. Because of how many nerves come out of it, the sympathetic trunk is a pretty big deal.

[alert type=”info” close=”false” heading=”Your Autonomic Nervous System: a brief primer“]

Just in case, I’m going to provide a simplified overview of your nervous system and thus, the autonomic division of your nervous system. Understanding this piece of the bigger puzzle will help make sense of what I’m about to ramble on about.

I’m sure we all remember from high school biology that we have our Central Nervous System(CNS). That’s pretty much your brain and spinal cord.

Then we have the Peripheral Nervous System (PNS), which you could think of (again, simply) as mainly the nerves that connect every part of your body to your CNS.

Your PNS is subdivided into your Somatic, Autonomic and Enteric Nervous Systems.

The Somatic Nervous System deals in voluntary movement (muscles!) and the Enteric Nervous System controls your gastrointestinal system.

The star of our show (for today), the Autonomic Nervous System has two branches: the sympathetic and parasympathetic nervous systems.

The Sympathetic Nervous System mobilizes the bodies resources for activity and is often characterized as the fight/flight side. The stress response is the sympathetic nervous system in action.

On the other end of the spectrum, so to speak, the Parasympathetic Nervous System conserves energy,takes care of the body’s basic maintenance functions and plays a big role in recovery from exercise/activity. It is often characterized as the rest/digestside.

There is a constant interplay or back and forth between your sympathetic and parasympathetic nervous systems. It’s a bit like a continuum and either system can be more or less dominant at any given time.

The Circus Artist-Athlete’s Thoracic Spine

Falsone pointed out that in individuals with a relatively flat thoracic spine, the posterior mediastinum is reduced in size. This reduction in space can mean extra stimulation for the sympathetic nerve trunk.

[alert type=”info” close=”false”]For the sake of clarity: if your body’s stress response is unnecessarily elevated on a regular basis, it risks compromising your ability to push yourself in training and your ability to recover from training. It also means carrying a little more muscle tone (tension) than you need to, which can limit your flexibility (among other things). It’s not something that you’re likely to notice right away because the effects are subtle. Over time, however, it may just mean you don’t have as much energy as you could, and you won’t make as much progress in training as you could.

Extra sympathetic stimulation basically means your body’s stress response is elevated almost all the time. No one needs that.

What caught my attention about this is that overhead athletes…you know, like aerialists…tend to develop a rather straight thoracic spine as a result of all the overhead reaching, arching and stretching.

Improving Overhead Range of Motion

When we encounter a circus artist-athlete who lacks full overhead range of motion, we usually employ a variety of strategies to help them to improve. Which strategies we use depends very much on what we see in their assessment. Assuming they have sufficient range of motion in their glenohumeral joint, the next most likely culprit is a limitation in their thoracic spine.

Expression of full, overhead shoulder flexion requires thoracic extension.

It used to be that we would recommend doing some thoracic extension work over a foam roller or with a ‘peanut’. However, inspired by Sue Falsone’s recommendations, over the past several months we have been having quite a bit of success in improving shoulder flexion by working on improving thoracic rotation.

The advantage to this is that we improve overhead range of motion without risking additional sympathetic stimulation.

Bending Backwards

But what if I want to improve my upper back flexibility for backbends? Or for my sweep?

I can imagine by now that you’re wondering: what about improving how well I bend backwards?

Well first, (giving a nod to Jim Donak here), bending backwards involves more than just bending your back. So that means making sure you’re getting the most that you can from hip extension. (There are other factors, such as lumbar extension and shoulder flexion. Improving lumbar flexion is well beyond the scope of this particular post and improving shoulder flexion, well, there are a number of things you can do for that as well, such as this, this or this).

And so, we circle back to increasing your upper back flexibility (or thoracic spine extension range of motion).

[alert type=”info” close=”false”] A couple of brief thoughts on that:

  • It’s worth noting that the thoracic vertebrae are not particularly well-suited to extension. What determines this is the shape of the individual vertebrae and how they interact with each other. I would love to provide you with some established norms for average extension range of motion for the thoracic spine, but the research review I’ve done suggests a range of anywhere up to 30 degrees. Anecdotally, my experience suggests that the people who have anything more than 10 to 15 degrees of thoracic extension are also very much on the bendier end of the spectrum. All of which is to say that it maybe be best to keep expectations of “upper back flexibility” modest.
  • That said,if you’d like more range of motion than you currently have, I would suggest keeping the following in mind:
    • If you are on the bendy-er side of things, please take your time with increasing your range of motion and make an effort to strengthen everything on all sides of your spine. If you have some congenital joint laxity, you’ll want to make sure you develop strength and stability alongside your increased range of motion.
    • If you are not one of the naturally bendy crowd, please take your time with increasing range of motion. Chances are your muscles and ligaments have some stiffness that will make increasing your range of motion challenging. More importantly though, those stiff tissues could shift the stress of your stretching efforts into the vertebrae themselves. No one needs a stress fracture here. [/alert]

For those looking to improve their thoracic spine range of motion, that represents one element of the larger picture of your overall training. One way we can look at the larger picture is in terms of the inputs to the system—where “system” really means your body (and mind, since the two can’t really be considered separately). In particular, it can be useful to think in terms of how the various inputs impact your autonomic nervous system.

Some inputs will stimulate your sympathetic nervous system while others will shift the needle in the parasympathetic direction.

(There’s room for a larger discussion on the balance between training and recovery here…but that’s for another time).

In the case of training thoracic extension, that represents a sympathetic stimulus. Now, it is, of course, possible that your life outside of circus training is a constant joy where you are rarely stressed, you make apoint of disengaging from technology about an hour before bed, you always get at least eight hours of sleep, you have a regular meditation practice and your performance nutrition game is on point…so, on balance, training a little extra thoracic extension won’t really throw your system off that much. However, just in case that’s not the case, it may be that trying to increase your thoracic range of motion will count as an additional stressor to your system.

In the name of balance, this is where we add efforts to shift things back in the parasympathetic direction.

Enter thoracic flexion.

By taking some time to remind your body about thoracic flexion, we get to relieve the pressure on the sympathetic trunk and provide an opportunity for some parasympathetic nervous system joy.

And here is an exercise that we often use to help with that:

All-fours Belly Breathing

This Postural Restoration Institute breathing exercise is one I learned from Eric Cressey. The video is not particularly exciting, given that it’s just me breathing.

Here’s what you do:

  • Position yourself on all-fours. Have your hands ahead of your shoulders (by about a hand-length) and your knees just behind your hips.
  • On your next inhalation—through your nose—press the floor away from you through your hands and your knees/toes (but keep your knees and toes on the floor) and round your back up into the biggest arch you canmake. Even tuck your pelvis. Imagine your inhalation filling up the rounded space your spine is making.
  • Exhale through pursed lips. Exhale slowly andfully. “Fully” means blow out alllllllll the air in your lungs. Towards the end of your exhale, notice how your obliques and deep core musculature shrink wrap your abdomen, like a corset.
  • Don’t lose the big arch you’ve made. In fact,think of each inhale as expanding your flexed spine upward and out while each exhale locks that position in place.
  • Do 5-10 breaths like this at the start of every training session, and, if you feel so inclined, also right after stretching your upper back.

In general, I like to use this breathing exercise with circus artist-athletes who might be a bit stuck in an extended position and for those who are working on finding their serratus anterior so that they can upwardly rotate their shoulder blades when they go overhead.

It’s not magic but adding some breathing to your regular routine can do wonderful things. Give it a try if you think this might be a good fit for your training (and for your life) and let me know how it goes. Because this is but one aspect of the bigger picture of how your train and develop your body for your art, if you’d like some help with the strength and conditioning piece of the puzzle (or you just feel like saying hello), please also drop me aline.

Until next time,