What Does Your Twist Tell You About The Strength Of Your Core?
Update 1/10/22: I wrote this blog post in 2014 (8 years ago at the time of this update!). I’ve learned a lot more about the human body, movement science, and the core since then, and instead of this blog post, I’d refer you to these more current, updated resources for information on this topic!
The Truth About Core Training – podcast episode with myself and Travis Pollen, PhD
Continuing Ed course: Applied Anatomy for Yogis: The Spine & Core
We know it’s important to have a strong, functioning core. But did you know that working our core muscles is only one half of the core strength equation? In order for our core to be truly strong, it must also be flexible and supple. As counterintuitive as it may seem, mobilizing our waist area with poses like twists has just as much to do with core strength as “core work” does. However, the traditional alignment we use for our twists in yoga often misses this important core strengthening benefit. In this article, we’ll use biomechanics to uncover some common twisting “cheats” so we can turn our twists into the awesome core-focused poses they should be!
A TIGHT CORE IS A WEAK CORE
(Update, February 2016: I really appreciate the sentiment of this section of this post, but since the time that I wrote it I have learned more and shifted my perspective. The term "tight" does not have an objective, scientific meaning, and there is also currently no evidence that I know of that suggests that strengthening a muscle will cause it to become 'short and tight', even though this a very commonly-held belief. I still love this blog post in general (especially the great photos of twisting alignment below), but this specific section right here is a tad outdated now.)
The first time I heard the statement that tight muscles are weak muscles, I was certainly dubious. Everyone knows that short, tight muscles are strong while long, loose muscles are weak, right? Isn’t that the way the body works? But it turns out that this common belief is actually an anatomy myth that doesn’t hold true once we examine the science of musculoskeletal function. It is correct that in order to be strong, a muscle must be able to contract - but this is only half of the movement equation. For true functional strength a muscle must have the ability to both contract and release.
When we talk about whether a muscle is strong, we’re really referring to how well it can “generate force”. This takes place at the level of the sarcomere, the basic contractile unit of a muscle. When a healthy muscle contracts, its sarcomeres generate force by shortening, and afterward they release and lengthen again so that they’re ready to shorten the next time the muscle is asked to contract. But if we work our muscles so much that they become short and tight, their sarcomeres are now in an overlapped, “locked short” position and can no longer release back to the place where they can contract again. Muscles like these are not functionally strong because they have a very limited ability to generate force.
So what happens to the muscles of our core if we “strengthen” them with a bunch of core work until they become short and tight? We might end up with defined abdominal muscles like your stereotypical six-pack abs, but if at the micro level, our sarcomeres are overlapped and can’t release back to their optimal force-generating position, our core is not physiologically strong.
MOBILIZING FOR CORE STRENGTH
For today’s purposes, let’s define the “core” as the area between the rib cage and the pelvis. We now understand that in order for this area to be strong, the muscles and fascia that live there must also be supple. One of the best ways to mobilize these tissues is through twisting. A twist takes place when we rotate our rib cage relative to our pelvis, our pelvis relative to our rib cage, or both at the same time.
Here’s a great visual that demonstrates this movement. My top hand represents a rib cage, my bottom hand is the pelvis, and the blue fabric in between is the muscles and fascia of the core:
No twist has taken place here because the rib cage and pelvis are facing the same direction.
Successful twist! The rib cage and pelvis have rotated relative to each other (see how the hands have turned?) and there's clearly a twist in the blue fabric.
Ideally a twist in our body would mobilize the muscles of our waist in the same way that these hands mobilized the blue fabric. Most of us are actually much stiffer through the waist than we realize, though, meaning that our true twisting range of motion is relatively small. But because of a prevailing idea in yoga that going "deeper" in a pose is better, we tend to bypass placing a load on the tight tissues of our waist in favor of moving where it's already easy for us to move, ending up in a shape that creates the illusion of a twist without mobilizing our core muscles much at all. Let me show you what I mean.
Here’s a wonderful yoga student named Craig (who also just happens to be my husband!)
Here are a few places where Craig can move really well in his body:
He can move nicely at his neck - see how he can turn his head all the way to the side?
He can also move his arms relative to his torso with ease.
In fact, Craig can combine these two movements to create a quite aesthetically-pleasing twist, wouldn’t you say?
But wait... is this a twist? Or does it just appear on the surface to be a twist? Well, if you use your anatomically-informed eyes to look at the Ganesha print on the front of Craig’s shirt, you’ll see that Ganesha is facing straight forward - he didn’t move through space at all. If Ganesha didn’t move, then Craig’s rib cage didn’t move, which means that his core didn’t receive a stretch at all, and this shape was, in fact, a twist “illusion”.
Another easy way to miss your best twist is to lift your chest instead. If we arch our spine when we twist, we’ll feel like we’re deeper in our twist because we moved more, but we’re simply mobilizing a place that wasn’t the target area of our pose - with the added drawback of creating compression in our lumbar spine. This kind of twist looks something like this:
Do you see how Craig has lifted his chest and tilted his rib cage backward in this example? He has also let his head rotate much further around than his rib cage, and if you look closely, you’ll see that his eyes have moved even further around than his head (!), all of which makes Craig feel like he moved deeper into his twist, when in reality his core didn’t rotate much at all.
In this final example, Craig is demonstrating a true core-mobilizing (and therefore core-strengthening!) twist:
He hasn’t arched his spine to create excessive movement in non-optimal places, and the change in angle of Ganesha shows us that he successfully turned his rib cage relative to his pelvis. An aligned twist like this is the essential ingredient to core strength that many of us have been missing. Your body will love it when you find it!
IN CONCLUSION...
In our continuing pursuit of an updated yoga practice that’s informed by biomechanics and anatomy, it’s helpful for us to look beyond the oversimplified categories we’ve been taught for our poses. “Spinal twists” and “core work” are actually intimately connected when it comes to core function. And as has become a central theme of my blog posts, in order for our twists to have a beneficial impact on our core, we need to let go of the idea that “deeper is better” and learn to work within our body’s true limits. The path of seeing ourselves accurately and clearly is an essential key to the transformative effects that yoga has to offer!