Many a times does it occur when a client will express concern over the arch in the lower back. Particularly when laying on the floor we’ll hear, “I can’t get my lower back to touch the floor!” We’re not totally sure where this obsession with having a flat back comes from, but there is an obvious need to be rid of it. We’ve even heard other yoga teachers use the instruction to “flatten the back” in classes. Now, in certain situations/asanas it is optimal to perform axial extension or be able to articulate in the pelvis and SI joint (although, sometimes yoga teachers will not know the difference between tucking the tailbone and tucking the entire pelvis), especially if you are stuck working in positions that have left you stiff and unable to access this kind of movement. Performing them can sometimes look like you are flattening your back. But the ability to extend/flex/rotate in every portion of the spine, despite the natural curve is only as important as it is to exist with and move with your spine in an neutral and healthy alignment, with your curves doing what they should for you.
There are 4 curves in the spine. Traditionally, it’s always been said that there are only 3, but many movement teachers (including ourselves) like to count 4:
Cervical/Lordotic Curve (Neck)
Thoracic/Kyphotic Curve (Upper Back)
Lumbar/Lordotic Curve (Lower Back)
Sacral/Kyphotic Curve (Sacrum)
These 4 curves work together to balance the weight bearing function of walking upright while negotiating the downward pull of gravity. Basically, humans walk on two feet while having to hold up a very large/heavy cranium at the top of the body It is a testament to the sophistication of engineering that is apparent in the spine, because it is the spine with its curvatures that allows homosapiens be bi-pedal with a tiny base of support, a high center of gravity, and super heavy weight a the top (brain). To more clearly illustrate, if one looks at chimpanzees or gorillas, they are of similar build to humans and can even have moments “walking” on their two legs. But for the most part they use all four of their limbs to execute locomotion. This is because they lack a vital curve that only human beings posess: The lumbar curve.
The spine is constructed in such a way that if you effect shape change in one part of it you inevitably effect shape change in another. For instance, when the gorilla (and other animals) want to “stand up” on their hind limbs they have to use the momentum of throwing their front limbs up and in front (any body every use a kettle bell?) in order to gain temporary balance on their hind limbs from which they can look around from an erect position. The fact that humans have a lumbar curve allows us to walk around erect all the time.
Here’s where that inevitable shape change comes in to play. When human beings develop their lumbar curves (known as the secondary curve) this development elicits a shape change that eventually becomes recognized as the cervical curve (another secondary curve). The lumbar and cervical usually begin forming around the age of 1, as crawling babies turn into walking toddlers*. For most of us, the secondary curves allow for the head, rib cage and pelvis to line up one over the other when we stand erect. This balance makes it much easier for us to carry the weight of these structures on relatively small support. To see how we tend to take the ease of walking for granted throw one of the elements out of alignment. Thrust out your ribs or pelvis and see what it’s like to walk then.
In fact, tight muscles, bad postural habits, and even scoliosis are often responsible for throwing off the balancing act of the curvatures. Remember shape change is effected throughout the spine. The 2 kyphotic curves balance the weight of the rib cage and pelvis and the 2 lordotic curves help us walk up right despite presence of the kyphotic curves. If you have a a tight lower back, can’t articulate pelvic movement, or have scrunched up shoulders this obviously affects the shape of your spine and the movement it is meant to help facilitate. We should not forget to mention that the spine has a springy quality to it, which exists because of how it has been structured and the fluid-filled disks that are sandwiched between each vertebral body. The structure and disks allow for that shape change to happen and also assists in the shock absorption of our bi-pedal behavior.
So what does this all mean when applied to a physical practice? Next time you are laying on your back don’t freak out if your lower back isn’t touching the floor. Be happy about it. But if it is a cause of discomfort and if you want to pull the knees to your chest to reveal the stress then there is work to be done on the muscles of that area. There can be many reasons for that. But don’t immediately think in order to relieve that discomfort that you need to flatten out the spinal curve, this could actually lead to injury later. Or if you hear about “flattening your back” in yoga classes, like in hinging up from forward bends and other standing postures, realize that this can be part of a practice that does not necessarily apply to sitting or laying down when not doing yoga.
If you are experiencing pain in the neck, shoulders, chest, lower back, or even problems breathing and headaches then get to a teacher who can help you get acquainted with your curves and teach you how to work with them to keep the structure of your spine healthy and balanced.
*There is much information we have glossed over in this post and that has been taken from books. If you want to explore more deeply we recommend reading, Yoga Anatomy by L. Kaminoff & A. Matthews (who happen to teach essential anatomy for all yogis and yoginis, right here in NYC at the Breathing Project) and Taking Root to Fly by I. Dowd.