"Every bone in every body is different. What is easy for one skeleton is impossible for another." These are the words of Paul and Suzie Grilley, who true to their name, "grill" this into their students every single day of their yin yoga trainings. I am so glad that they do this because as a yoga teacher (or a movement teacher of any kind really), this is so imperative to understand for the comfort, safety and psychological welfare of your students and clients!
It is completely irresponsible to tell a room full of yogis that "one day their backbend will deepen if they just keep working on the posture". Or that they "should be working the hardest on the yoga posture that they find the most difficult". (Side note, if you find a posture difficult because it is creating pain in your body, that is a really good sign that you should stop and investigate before you potentially get hurt).
The truth of the matter is, that over the course of a yogi's asana journey, their soft tissues are the part of the body subject to the most change. The bones however, are a fixed shape and orientation. And unless there is degeneration, pathology, or anomaly occurring, no amount of yoga is going to change the shape of your bones. In my humble opinion, more yoga teachers need to understand this in order to facilitate their classes in a way that is honest, supportive, and psychologically healthy for their student community.
A back bend is a classification of a yoga posture that moves the spine into extension. Contrary to some yogic instructions, the spine is not able to bend backwards at every single intervertebral junction. The places where this is most likely to occur will be the places in the spine where a kyphotic curve is turning into a lordotic curve, typically between C7 and T1, T12 and L1, and L5 and S1.
Look closely at some pictures of yogic backbends and you will see that there are very clear hinge shapes occurring in the spine during extension. It is not an even curvature!
The bony structure of the spine that creates a compressive force stopping yogis from being able able to extend their spine any further, are the spinous processes along the back of the spine.
If these structures have met, and are pressing into each other and the soft tissue surrounding them, no amount of forcing the body, will create a deeper backbend.
In fact, this kind of compressive sensation is likely to be painful! (Don't get me started on how the subculture of yoga encourages students to ignore their pain!)
Some students will feel this compression very quickly as they press up into cobra pose, or upward dog.
It can be described as a "pinching, hard or stuck" sensation. And by association it can swiftly create a strong aversion for this kind of yoga posture (whenever I meet a student who tells me that they "hate" backbends, I feel pretty confident that they are experiencing painful compression in their spine during the posture.)
This can create a real sense of panic or even dread when they hear the teacher announce that the whole class is going to be working on full wheel, bow pose or dancers pose today.
This internal feeling is often compounded by the verbal statements of "one day your back will be able to bend deeply" or some other negligent claim. (Can you tell I have a huge problem with this kind of language in yoga classes!)
To illustrate my points, below are two samples of lumbar spines (courtesy of the bone images published by Paul Grilley). Imagine that these two lumbar spines belong to the bodies of two yogis laying on their belly; the "body" of the spine is at the bottom of the image, and the "spinous process" is at the top of the picture.
Whilst neither lumbar spine is in its natural curve, and no longer has its intervertebral discs or soft tissue present, there are significant differences in the bone structure.
Lumber spine 1 (below left):
The spinous processes are all different heights (especially the fourth, which is quite short).
There is a modicum of space between each spinous process.
Lumbar spine 2 (below right):
The spinous processes are all roughly the same height.
There is much less space between each process as compared to Lumbar spine 1 (especially between the 4th and 5th process which are almost already in contact).
So which spine do you think is going to meet compression first in any kind of backbend?
Lumbar spine 2 is the correct answer. Also, it doesn't matter what kind of backbend you practice be it bow pose, cobra, bridge, or scorpion, the spine will do the exact same thing in every one of these postures to the degree of force at which you apply to the movement of extension!
People don't develop the ability to backbend deeply by forcing their body into yoga shapes. It was made possible by the already inherent shape and structure of their bones. Upon discovery of this, a yogi may wish to practice lots of different kinds of backbends,(thus conditioning the strength and flexibility of their soft tissue in the process), but the reason they are able to do it in the first place, is because their bones allowed for it (this also applies to ballet, gymnastics, martial arts etc).
Because of the space between the bones and the shorter length of process 4, lumbar spine 1, may find that in their "deepest expression" of a backbend, the place where the backbend is happening will be quite obvious. It will probably occur between L4 and L5, or even L3 and L4 as the spine has more room to move before something will be pressing up hard against that shorter spinous process. You can clearly see the sharp angle at where the backbend is occurring for the student 1:
Thoracic spine is straight (extension does not happen through the thoracic)
The backbend is primarily happening at the junction between the thoracic becoming the lumbar (a kyphotic curve is transitioning into a lordotic curve)
The shape of the bones at this location, and the change in orientation of how they angle, allow for a deeper degree of extension before compression stops the movement going any further
This is a classic hinge.
The student 2 is in cobra pose, and you can tell from this image that they are using a moderate amount of strength in their arms to push the chest up off the floor. If you look at the curvature of the spine, there is no obvious hinge happening. It is possible, that if they applied more force, and pushed up off the floor into upward dog, a hinge might occur.
For discussion sake, let's say that this student has a lumbar spine similar to Lumbar spine 2; in this shape they might already be feeling the sensations of compression in their lower back, and this might be their "deepest expression" of the backbend. So if they continued to add more force in this direction, the spine cannot fold any deeper, what might happen, especially if they straightened their arms, is that their hips might rise up off the floor.
Their thoracic spine is also straight (the thoracic spine is not designed to extend, at all!)
If the body has met compression and more force is added in that direction, movement will only happen where it can (usually the next joint up or down from the place that is compressed).
There is no obvious hinge for student 2
Both of these backbends are fantastic! There is nothing wrong with either of these yogi's asana, unless you have placed undue success parameters on what the shape should look like!
Every bone in every body is different. What is easy for one skeleton is impossible for another.
You are not less than if you meet compression early in your spine during backbends. You are no less of a yogi! You have not failed some yogi exam towards enlightenment. These are your bones and they are incredible! You are incredible!!
If you are feeling compression in your spine during a backbend; that hard, stuck or pinching sensation, it might be beneficial to come out of the pose slightly to reduce that sensation, especially if it is making you hold your breath, is causing you pain, or making you feel anxious. You don't have to fold your body in half to receive the benefits of a backbend.
Only the people with spines shaped in way that allow for that, will have the room in their body to do that. Nobody is getting closer to god because they can fold their body in half!
For teachers, please gently reflect on the language you are using in classes around this important conversation. It may be more useful to ask your students what they are feeling in a posture, rather than telling them what they "should be able to do" if they just "practice hard enough."
I hope you found this article helpful.
Love Karina x
(Pictures of the lumbar spine courtesy of Paul Grilley)