Exercises Every Aerialist Should Do: the problem with the ‘hollow’ body

I have used it before in the past and I’ve worked with others who have used it. In certain circles, it’s quite popular and used on a regular basis. For those ‘in the know’, the word hollow is synonymous with an abdominal drawing in and the most commonly used teaching cue for it is “pull your belly button in towards your spine”. As it turns out, hollowing might not be the best way to go.

Whether you’re a flyer looking to build some height in your swing or figure out how to do a layout or you’re hanging from a bar and about to invert or even if you’re just climbing the silks, you should have the strength to do a solid hollow body position on the floor. Hold that position for at least 60 seconds and progress to holding that position while hanging from something. The key detail is what makes for a solid hollow body position?

Before we get into all of that, let’s take a moment to set the stage. Many of us identify very strongly as being circus people. But before we were circus people, we were (and still are) human people. One thing all human people—humans, for short—have in common is that we all have spines. Our spines house and protect our Central Nervous System—CNS, for short. Our CNS is kind of a big deal.

So, as humans doing circus, we are often encouraged to be engaged or tight. As I’ve mentioned previously, keeping your core engaged is fundamentally about developing spinal stiffness. Stiffness is necessary for spinal stability. Why is spinal stability important? It prevents spinal segments (your vertebrae) from moving in directions other than those you intend. Basically, it stops your vertebrae from slip-sliding all over the place…which is something that leads to joint degeneration and nerve damage (or just prolonged nerve aggravation) that tends to lead to back pain. No one likes back pain. Lots of people accept it as a consequence of aging or long-term participation in sports/weight lifting/activity, but that is nonsense because back pain is totally preventable…but I digress: the real take-home point here is that the primary function of your core musculature is to prevent movement in your lumbar spine rather than to cause it. And very often, the way we are encouraged to be engaged or tight is by being hollow or hollowing.

What exactly do we mean by abdominal hollowing? This is the pull your belly button to your spine thing. Try it now. Pull it in and it feels a bit like you’re trying to look thinner in front of the mirror.

What’s going on here?

Abdominal hollowing allows us to isolate and activate the transversus abdominis (TVA) muscle. (This is the one that wraps around your whole core and creates a compressive, corset-like feeling). This triggers a co-contraction of the multifidus muscle in your lower back. Together, they serve to improve spinal stability.

Sort of.

A while back (in the 1990s), researchers in Australia noticed that in healthy individuals, a fraction of a second before any movement (like, pulling on the silks to begin a climb or lifting the legs to invert), the transversus abdominis would activate. In individuals with low-back pain, they found there was a delayed response from the TVA. The conclusion was obvious: for physical therapy patients with low-back pain, teach them to activate their TVA in order to fix the dysfunctional motor pattern. And thus, abdominal hollowing was born.

Sounds good to me. What’s the problem?

There’s no problem, really. It’s just that researchers are curious sorts, always wondering if there’s a better way. As recently as 2007, a number of them have been questioning this abdominal hollowing thing. They’ve been looking into low-back pain and have found that it’s not just the TVA that has an altered recruitment pattern. People with low-back pain have a number of muscles that aren’t firing when they should be. It seems that it’s more than just one muscle that contributes to the problem.

Moreover, it seems that hollowing might not provide the most stability. Any given muscle can create force and/or stiffness. Stiffness is always stabilizing. Since hollowing is a core stabilization strategy that only involves two muscles, it might make sense that the amount of stability provided is actually not that great. And so it was (in an overly simplified kind of way) that Dr. Stuart McGill, Professor of Spine Biomechanics at the University of Waterloo, Ontario, gave us abdominal bracing.

Pretend like someone is about to punch you in the stomach. Brace for impact. This is abdominal bracing.

With bracing, you are switching on your entire core: transversus abdominis, your internal and external obliques, and of course, rectus abdominis. And your lats and the musculature of your lower back (including the aforementioned multifidus). This synergy of muscular stiffness produces superstiffness. According to McGill, et al., the idea is that abdominal bracing allows you to lock your ribcage to your pelvis in order to eliminate unwanted spinal twisting, flexion or hyperextension. For our purposes in circus, the real key becomes control.

In order for you to perform well in just about any circus art, you need to be tight/engaged. But wait! There’s more! Once you figure out how to be tight, you also need to figure out how to move. McGill’s superstiffness concept is built around the idea of eliminating unnecessary movement in the lumbar spine—and there’s good reason for that. Too much movement—uncontrolled movement—of the lumbar spine can create a whole host of problems for people (think: hey, I’m too young to have back pain!). This is why I emphasize the idea of controlled vs uncontrolled movement. So much of circus calls for back bends or twists. The key becomes developing a sense of when to be superstiff and when to be compliant. Being compliant is a matter of knowing when and exactly how much to ease off from that place of super-stiffness.

But that’s a topic for another day.

For now, let’s come back to our updated ‘hollow’ body:

Start on your back on the floor with your arms by your sides. Knees are bent and feet are flat on the floor. (Think 90-degree angle at your knees). Press your lower back into the floor.

Here’s where it may be different from what you’re used to:

Take a full breath in and then exhale slowly and forcefully. Feel your ribs come down and lock into place. Someone could drop a coconut on your stomach now and it would just bounce off. (That thought brought to you courtesy of the movie Kickboxer).

Now, maintaining your core stiffness, straighten your legs (and point your toes).
Slowly lower your legs towards the floor —without letting your lower back lose contact with the floor. Only go as far as you can without breaking form.

The goal for every aerialist and flyer should be to be able to lower your legs almost to the ground (again, without losing contact between the floor and your lower back) and hold it for 60 seconds.

Was that different from what you’ve done before? Harder? Too easy? Let me know in the comments and maybe we can talk about how to progress this to hanging from a bar/lyra/piece of fabric…

And this is, of course, just one piece of the larger puzzle that is your whole-body strength and conditioning plan. Circus arts require a foundation of whole-body, general strength upon which to build the specific-strength needed for all of the cool tricks and skills you want to do.

Need some help figuring out just what to do? Drop me a line. (Do people even say that anymore? Am I dating myself?) I’d be more than happy to help you with some ideas.Or maybe you’d like me to do the thinking for you so that you can just get down to the business of getting stronger…well, we have things for that, too.


1 thought on “Exercises Every Aerialist Should Do: the problem with the ‘hollow’ body”

  1. Jonathan F.V.

    Nice. I really hate when people tell others to pull their belly button towards their spine, it’s stupid. I like telling people to start in a crunch position (legs up at 90 degrees), then squeeze their abs so that their ribs get closer to their hips. Ideally, their upper torso will lift a bit and their shoulder blades won’t touch the floor. From there, I sometimes tell them to only extend one leg at a time, to feel how they can extend their legs without anteversion of the pelvis, then they extend their legs out and down either until the position is satisfactory or until they cannot do so without breaking form (lower back coming off the floor). For more advanced students, I sometimes walk on their stomach, and teach them to breathe even under intense bracing.