What Causes Low Back Pain?

If you’ve arrived on this page, you’re probably suffering from some low back pain. Or, you have students that are. Understanding lower back pain is a complicated endeavor. So we’ve tried to organize all of the elements you should keep in mind if you’re exploring why you, or someone you know, suffers from low back pain.

Unraveling the mystery of low back pain

There are unfortunately many different reasons why we experience low back pain. If we’re experiencing low back pain, then it’s only natural for us to mentally cycle through the most popular reasons this could happen. And those are usually the worst possible scenarios we can imagine.

Whether it’s muscular, a herniated disc, a bulging disc, the piriformis muscle, sciatica, or other factors that contribute to lower back pain, it’s always important to take the time to assess the situation. The assessment should lead you to a theory about where it is coming from. And that should then lead you to test that theory and see if it is true.

I realize that this can be complicated. It’s also difficult to self assess many of these potential problems because you’re so close to the problem itself.

Gather information about the problem

Here are some questions that you may want to ask yourself as you read this article. Write down the answers to these questions to paint a more objective picture for yourself of what is going on. Then hopefully so you can work your way to the source of the problem and not just deal with the symptoms. Clearly identifying the details of your low back pain situation is also very important if you decide that it is time to seek out an assessment from a wellness or medical professional.

• When does your back hurt? Does it hurt when you’re sitting, standing, forward bending, backbending, or at some other time?
• What type of pain is it? Would you describe the pain as sharp, dull, achy, shooting, or as something else?
• Is the pain constant or intermittent? Does it always hurt when you do X or does the pain seem random?
• Is the pain always in the same place or does it seem to move around?
• Can you find a particular spot that mimics the low back pain you experience?
• Is there anything that you do that definitely makes the pain worse?
• Is there anything that you do that definitely makes the pain better?

The anatomy of the low back

Low back pain is common in the general population and in yoga. In my book, Functional Anatomy of Yoga, I mention that low back pain is the second most common reason that people visit a doctor. In our study on yoga injuries, we found that low back pain was the second most common location for pain and injury in yoga. So, why is low back pain so common? And what can we do about it in yoga?

What muscles are found in the low back area?

One of the difficulties with the idea of a “low back” is in identifying where and what we’re talking about. The low back is not a specific structure. What we’re most commonly referring to are the lumbar and sacral areas of the back of the body. It’s important to remember that we have three-dimensional bodies, however. Our deepest layers of tissue don’t really reside on the back or the front of the body. They’re in the middle. They can, however, be related to or create tension on the back of the body. In fact, even muscles on the front of the body can create problems and low back pain.

So, let’s list out the muscles that are found in the lumbar and sacral area, or that could affect tensional patterns there:

• Quadratus lumborum
• Psoas major
• Iliacus
• Transverse abdominis
• Internal obliques
• External obliques
• Rectus abdominis
• Multifidus
• Rotatores
• Erector spinae muscles
• Thoracolumbar aponeurosis
• Piriformis
• Gluteal muscles, especially gluteus maximus

What structures are found in the low back?

There are plenty of individual structures in the low back. However, we can group them into three main structures: the pelvis, the sacroiliac joint, and the group of lumbar vertebrae. These structures represent the main bony structures and joints that transmit force up and down into and from the lower back.

The pelvis

The pelvis itself includes three bones that are fused together. It is a central hub, or crossroads, in the body. It receives load from the spine above that is transferred down through the legs. And it receives force from the activity of the legs that is transferred up into the pelvis and then upward into the lumbar spine. The muscles in the lumbar and pelvic areas of the body are in multiple layers and have fibers running in different directions. This keeps the right balance of tension while transferring the forces of movement up and down the body. If that balance of tension is off in some way, more force can be transferred to other areas of the body, like the lower back. We can feel pain or tension in the low back area as a result.

The SI joint

Sitting in the middle of all of this is the sacroiliac joint (SI joint). I’ve written about that a number of times. There’s a lengthy post about that which you can read here. Those same tensional patterns that cross through the pelvis are crossing the SI joint as well. As a result, if the SI joint gets “out of place” or tensionally held in a less than optimal position, this affects the low back and the sensations you feel there. The importance of this joint for helping to transmit forces through the pelvis, up to the lumbar, or down to the legs below, should not be underestimated. And that’s why I’ve separated it from the pelvis.

The lumbar spine

Finally, we have the lumbar spine itself. Although there are technically five lumbar vertebrae, it’s easier to think of them as a group. They are larger and thicker than the vertebrae that are above them, implying that they are designed to hold more weight than those above. This downward force from holding additional weight, along with the curvature of the lumbar spine is, in a sense, less than ideal. Our bodies are trying to balance out strength in structure and freedom of function. The low back is a good example of where evolution had to work hard in bringing us upright.

Lumbar curve structure

The lumbar curve is typically a much deeper curve than it appears from the outside. What I mean by that is the thick musculature of the erector muscles in this section of the spine makes it seem like the back is flatter than it really is. The last lumbar vertebra (L5) is sitting atop the sacrum (S1) with a disc between them. You’ll often find the top of the sacrum slanted down at approximately 45 degrees.

The lumbar spine should gracefully curve from that 45 degrees until it comes all the way up to the thoracic spine and starts curving the other way. Remember that the lumbar spine is primarily designed to do flexion and extension, or forward and backward movements. This curve lives within that flexion and extension. In this case, we might refer to this lordotic curve as hyperextension. I mention this now because one very large contributing factor to lower back pain and how it relates to the lumbar spine is the loss of this curve!

What causes low back pain?

Low back pain in general can be the result of so many things. That includes, but is not limited to: strained muscles, repetitive sports or activities that create muscular imbalances, vertebral deformities or dysfunctions, congenital curvature conditions like scoliosis, dysfunctions causing pressure on the sciatic nerve (sciatica), and more.

Some (but definitely not all!) causes of back pain include:

• Herniated or bulging discs pressing on a nerve root
• Piriformis syndrome
• Chronically short hip flexors (especially iliopsoas)
• Tensional pattern around the SI joint
• Chronically short glute max
• Chronically short lumbar erectors
• Lower crossed syndrome
• Trigger points
• Hormone changes during a menstrual cycle
• Pregnancy

What does research say?

There are many many studies where researchers have tried to identify the specific cause of low back pain because the experience of pain in that region is so common. But really all that the research community has at the moment is more questions. There is no one answer to the question, what causes back pain. Instead, there are thousands of answers. There are really as many answers to that question as there are people. When working with yoga students experiencing low back pain it’s important for us to keep this in mind and avoid the trap of thinking that we have the answer. We need to be open to exploring with the student to find a way forward that works for them.

Where is the pain coming from?

Another important thing to keep in mind when working with low back pain is that the site of pain is often not the source of the pain. The source of the pain can be tension somewhere else in the body. That said, sometimes the site of pain is also the source of pain. There is potential for pull to come from just about any direction when we are looking at the low back. There is also potential for dysfunction to be localized from a source in the low back itself. In yoga, unless there has been a previous accident, injury, surgery, etc. that we’re dealing with, we’re more likely to come across the generally achy, throughout-the-low-back, and comes-and-goes kind of low back pain. This kind is more likely to have a muscular or tension pattern cause.

Because the cause of low back pain is so variable, it is especially important that if you are experiencing frequent low back pain, especially if it occurs outside of your yoga practice, that you go see an appropriate medical professional and have a thorough assessment. Some back pain symptoms, or recovery from an acute injury or accident, may mean that any yoga practice is contraindicated until you have the go-ahead from your doctor to resume that kind of movement.

Postural problems and low back pain

One of the most common postural problems associated with low back pain is prolonged sitting. Of course, everyone sits. The problem is when we don’t counteract that prolonged sitting with exercise or activity. In this way, we often find activities such as yoga helpful.

Generally speaking, as a society, we sit more now than we probably ever have. While sitting, most people lose their lumbar curve during that period of time. When this is compounded by time, what you get are short hip flexors, tight abdominal muscles (tight in this case doesn’t mean strong), and an imbalance in musculature. Just at a muscular level, this can create pain and dysfunction in the low back.

Structural issues from sitting

This particular pattern can also lead to structural issues. In this case, it can lead to a reduction in the lumbar curve, which is not a good thing! This can lead to muscular pain. And it can lead to a compression of the front of the vertebral column which can compress the discs that sit between the vertebrae. Over time, this alone can lead to disc issues such as bulging discs, herniated discs, or eventually rupture of the disc.

All of this is why many people with lower back pain feel relief when they are in backbending-type positions. I typically use this as a clue that the hip flexors and/or abdominals are too tight. Although prolonged sitting may be at the top of the list, any activity that creates an imbalance between the multitude of muscles that cross the lower back can be a problem.

Muscular issues and low back pain

Erector spinae

Sometimes, the source of the pain is simply where you feel it. It’s very possible that depending on the activities you do, the muscles of the lower back themselves are the problem. I have seen this a number of times in students who are working really hard on their backbends. Meaning, they are spending a lot of time in their practice tightening the muscles in the back, generally in an effort to make their backbends deeper. Sometimes it’s the muscles themselves that are sore. And sometimes when there is a more generalized dull achiness, I check for trigger points.

In these cases, I have found that there are two key muscles that get involved. The first is the erector spinae group of muscles. This group consists of three muscles from medial to lateral called spinalis, longissimus, and iliocostalis. In the lumbar region, they are extremely thick with layers of fibers. Any part of them can become overworked and dysfunctional.

If I believe a problem is coming from this group of muscles, because I am a licensed massage therapist, I will palpate them and check for tenderness. If I find these tissues to be extremely sensitive to pressure, I will also check for trigger points near the top and outer edges of the iliocostalis muscle. When activated, these trigger points tend to send a referral pattern down the back on the same side, sometimes around the SI joint and further into the gluteals.

Learn all of your muscles

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Quadratus lumborum

Quadratus lumborum (QL) is another common culprit in lower back pain. People often describe pain originating from QL as a deep ache or generalized pain on one side of the low back. Pain from this muscle often presents itself more clearly in postures that are one-sided. It also comes up when someone is doing a deep backbend posture where they continually emphasize one side more than the other. This happens, for instance, when someone is trying to deepen the posture one side at a time and the lower back has to side bend (laterally flex) in order to reach the hand to a foot, ankle, or another part of the body.

Palpating this muscle is a little more complicated, but it is possible when heading in from the lateral side of the body. But don’t confuse it with the edges of the iliocostalis mentioned above. Trigger points are also common in this muscle when it is dysfunctional. The referral sensations from trigger points sometimes wrap around the side of the body or down into the SI joint area and gluteal region.

Tight abdominals

Let’s assume for a moment that your abdominal muscles are tight and part of the problem. If that is the case, this can be part of a shortened front body that removes the curve of the lumbar spine. This can compress the front of the discs and create long-term problems at either the bony or disc level of structure. Please include an assessment of your abdominal tension if you have low back pain. If they are tight, they need to be released, lengthened, and then possibly strengthened again.

Many people associate tight abdominals with a healthy core. I wouldn’t say that this is false, however, it’s not as simple as that. You can have abdominals that are tight and healthy, but you can also have abdominal muscles that are tight and causing dysfunction. The dysfunction caused by the abdominals can be on a muscular level or they can simply be having an impact on posture that is not healthy. The line between these two is not easy to draw. But for our purposes here, if you have back pain, that may be the line that is drawn for you.

What about the core?

I know many people believe that if you have back pain you need to strengthen your core. And most people think this means that you should strengthen your abdominal muscles. The basis of this belief is one that may or may not be true. The basis of this belief is that the pain, in this case, your low back pain, results from a weakness that needs to be strengthened. I don’t know why this is the default belief, but it often is. The tricky part is that it can be true.

Tight hip flexors

Tight hip flexors don’t come with the same underlying beliefs as the abdominal muscles and their strength. By tight hip flexors, I primarily mean rectus femoris from the quadriceps group, the psoas major muscle, and the adductors. These hip flexors often have an impact on the structure that surrounds the low back. They should definitely be evaluated if you have low back pain.

To start with, tight hip flexors can statically hold the pelvis in an anterior tilted position. This means that when standing, the pelvis tilts forward and down. That pelvic placement increases the amount of curve in the spine and shortens muscles on the back of the body in the lumbar spine, such as QL and the erector group. Over time that can lead to dysfunction.

Chronically tight hip flexors can also impact backbending postures. If the pelvis is held in that anterior tilted position, when you press up into a full backbend or wheel, you increase your chance of compressing your lower back. This is because it’s more difficult for the pelvis to tilt posteriorly, which is what we want the freedom to do while in a backbend. This is not to say that the pelvis is in a static posterior tilt position in a backbend. It means that we want to be able to undo some of the anterior tilt in order to move freely and comfortably when backbending.

Structural vulnerability and low back pain

In an effort to get more specific for you, let’s talk about some of the most common structural issues that contribute to low back pain.

Sacroiliac joint

We have already written about the SI joint extensively in numerous articles. It often mixes in with the larger context of low back pain for a few reasons. One is that the location of the SI joint is essentially at the very bottom of the lower back. A second reason is that pain from the SI joint can radiate upwards into the lower back. Finally, muscles in the lower back can refer pain into the SI joint through trigger points.

I often describe the SI joint as sitting in the middle of a kinetic chain of joints. That describes the interrelated nature of these joints. The first joint is the hip joint. The second (in the middle) is the SI joint. I put the lumbar spine as the third joint sitting above the other two. I know the lumbar spine is more than one joint, but functionally, it works in my mind.

The reason I think about the SI joint as the center of that chain of joints is because it is a key to muscular balance around the hip and the low back. Imbalance at the SI joint is often part of the larger low back pain story. As a result, lower back pain may come from a dysfunctional SI joint. Or, lower back pain issues may create SI joint problems. Understanding the relationship between these two things can be critical for proper assessment of the underlying problem so you can work on it.

Junction between thoracic and lumbar

Where the thoracic spine meets the lumbar spine (the joint between T12 and L1), small joints that link the vertebrae together (zygapophysial or facet joints) change shape and direction. The shape of these facet joints on the top is different than those on the bottom. The facet joints at the top of T12 are the same as the rest of the thoracic spine, which allows for twisting and side-bending, but less backbending (hyperextension) and forward bending (flexion). Those are ultimately limited by the rib cage, sternum, heart, and lungs inside that cage. The facet joints at the bottom of T12/top of L1 are the same shape as the rest of the lumbar spine. This allows for lots of flexion and extension as well as side-bending, but strongly limits the ability to twist.

As a result of this change in shape at the top and bottom of these vertebrae, this area is sometimes referred to as the lumbo-dorsal hinge. Because of the change in shape, there is a potential increase in forces coming from above or below it. This could also take the form of a reduction in the transmission of forces, which have nowhere else to go. The amount of increase in force through this area depends on the type of movement and the intensity or depth of that movement. All of this together makes this area more vulnerable, although it would typically show up muscularly as a result of these structural considerations.

Shape of the lower back and its function

As I mentioned above, the shape of the lumbar vertebrae themselves can sometimes lead to problems. We both have and want curves in the lumbar spine. Also, as I mentioned, the top of the sacrum typically angles down close to 45 degrees. Sometimes it’s more than that and sometimes less. What this means is that L5 and L4 in particular, are in a sense (not literally), sliding off the top of the sacrum. The body recognizes the issue here and has additional ligaments that help hold those two vertebrae from falling forward. Above that, you have L3, L2, and then obviously L1. L3 is the center of the curve in the lumbar region of the spine.

From a functional standpoint, the section of the lumbar spine that is above L3 is a softer lumbar curve that is on its way to neutral and then will transition, of course, to the curve of the thoracic spine. The problem area is typically below L3, where not only is the positioning of the vertebrae angled down and forward, but the positioning creates a deeper overall lumbar curve. When we forward bend from the spine, or sit for long periods of time for work, we undo this portion of the lumbar curve more significantly than the portion at the top of the lumbar curve.

This leads us to the next problem that often follows from that and occurs in the lower lumbar region: disc dysfunction.

Disc dysfunction

This is probably the most common and well-known dysfunction associated with low back pain, for good reason. If you have dysfunction of a disc in the lumbar region, this can be extremely serious and painful. The discs in the lumbar region are most often involved in dysfunction. Of those, the discs most commonly involved are those sitting between L4/5 and L5/S1.

There are a multitude of reasons why discs are involved in dysfunction.

• Genetic
• Postural (scoliosis)
• Accidental (lifting a heavy object)
• Repetitive movement (work-related)
• Lack of movement (sitting)

Disc degeneration

It’s also worth mentioning that sometimes the discs are simply wearing out or degrading over time. Sometimes there is a “straw that breaks the camel’s back”. It pushes a disc over the edge into injury. This scenario is extremely difficult to predict. Recently, a diagnosis that I hear about more often is called degenerative disc disease. I would suggest that this may be the most predictive version of disc dysfunction. However, it’s important to note that essentially everyone’s discs are slowly degenerating. In the case of this particular diagnosis, what that means typically is a loss of space between the vertebrae themselves, or that the fluid inside the discs is decreasing.

The complexity of spinal discs

The vertebral discs, like any of the items listed in this article, are worthy of an article themselves. So, whether you have degenerative discs, a bulging disc, a herniated disc, or a ruptured disc, suffice it to say that any of these can create low back pain. But I will also note that there are people with these conditions who do NOT exhibit low back pain. I don’t say this to confuse you, but instead to point out how complex low back pain and any other condition may be. If you believe that you do have any of these, then understand that the only way to confirm that is with an MRI. You should also not assume that because you have low back pain you have any of these issues.

It is also important to note, as we circle back to the lumbar spine where these problems show up the most, what can contribute to some of these dysfunctions. I spent some time discussing prolonged sitting already. In that scenario, most people decrease the natural curvature of the spine, especially in the lumbar region. When the lower vertebrae are straighter than intended naturally, there is a small pressure increase in the front of the disc. If this happens now and again through movement, that should not be a problem. But, if you total up hours upon hours of sitting, this can add to slow degeneration and compression.

Working with low back pain in yoga

The relationship between back pain and yoga goes both directions. The growing body of preliminary research suggests that some yoga can reduce or eliminate some back pain. The wrong yoga practice for the wrong person can also cause back pain. What’s the main difficulty in defining the relationship between yoga and back pain? Both the word “yoga” and the phrase “back pain” can mean so many different things!

• What kind of yoga are we talking about?
• Is it a gentle yin style practice, a vinyasa style practice, a yoga therapy session?
• What poses are we talking about? Backbends, forward bends, twists?
• What do we mean by back pain?
• Where specifically is the pain and what kind of pain is it?
• What directions and kinds of movement make it feel better or worse?
• Is the pain in a joint, like the sacroiliac joint or a vertebral joint, or is the pain in the soft tissue?

There are so many questions we could ask here because there are so many variables. Use the answers to these questions to help you get closer to what it is that may be contributing to low back pain.

Is there something you need to stretch or strengthen?

There are good reasons why there is a never-ending, ongoing debate about whether there is something you need to stretch or strengthen to address back pain. For some reason, when students have pain they often assume that it implies a weakness that they need to strengthen. But, back pain can come from so many different sources. And the answer is often more complicated than we’d like it to be. The answer to the question of whether I need to stretch or strengthen could be either or neither of those depending on the cause. For example, what if it’s structural?

What’s especially difficult is that the source of back pain is notoriously hard to determine. And it can come from more than one source simultaneously. So, how do we know how to sequence, construct, or modify our yoga practice with respect to having a happy low back? Ultimately, some amount of gentle trial and exploration may be necessary with our experience and kinesthetic feedback providing the best answer to what works best for our body.

Overdoing it in the stretch

In yoga, we can experience pain in the low back if we over-do the actions that happen easiest there: flexion and extension. It’s possible to over-stretch this area, both by over-doing forward bending and by dumping too much into the lower back in backbending. It’s also possible to over-do the stretch in the lumbar area if we try to go too far into a pose and other adjacent muscles in the chain don’t allow for that much movement yet. For example, if our hamstrings are very tight and we force ourselves to go deep into a seated forward bend, we may over-do it and feel pain in the low back.

The most common postures where low back pain comes up in yoga are forward bends and backbends. This makes sense because, as we have already discussed, the movement that is most accessible in the lumbar spine is flexion and extension. In one sense, what we are often looking for when we are trying to avoid low back pain in yoga is how best to distribute a stretch throughout the whole spine, rather than over-emphasizing the lower back. This means we need to identify where we are limited in a posture and move more of our attention and focus there.

The low back and forward bending

Forward bending, seated or standing for that matter, should generally be made of two-thirds hip joint movement and about one-third movement from the spine. This is a general ideal that I look for. If we are tight along the back of the body, and especially in the hamstrings, this is going to make it more difficult to create that two-thirds movement at the hip joint. The literal movement we are talking about is the pelvis tilting forward and down around the heads of the femur. If you don’t recognize the point at which this movement stops, you may end up emphasizing the spinal movement too much and putting too much strain into the lower back.

Working with your forward bend

To alleviate this, and assuming you do have tight hamstrings or are unable to move your pelvis for another reason, you can lift the pelvis by sitting up on something like a block or a folded mat in order to create more anterior tilt of the pelvis. This alone may be enough to bring the pelvis back to neutral, putting more of the stretch intention into the hamstrings and taking some of the tension out of the lower back muscles.

There are times where the opposite is required. If you are very open along the back of the body and are generally flexible with no problem in a forward bend, then it’s possible that you need to hold back a little bit. I have often undone the forward bending of very flexible students by helping them to undo some of the anterior tilt in their pelvis. In this case, we can choose to back out of the seated forward bend and intend our pelvis in more of a posterior direction, which really brings us closer to neutral.

The low back and back bending

Depending on the source of the problem, moderate backbending can alleviate low back pain. But since it’s so complicated, it’s also possible that backbending is the cause of the problem. This is why we’ve emphasized asking questions and exploring movement so that you know what is contributing to or reducing your low back pain.

When it comes to backbending we often focus on deepening our backbends, that is, making them look less and less like a coffee table and more like an arch. The difficulty here is that this is an entire body posture that relies on the interrelationship of all parts of the spine, the pelvis, the hips, and all of the musculature I talk about in this article. If any of those parts and pieces are ignored or over-emphasized, this can cause trouble.

Working your backbend

To bring it into focus, let’s talk about the most common pieces. It seems obvious, but we need to focus on distributing the movement throughout the entire spine, not just the lower back. That often means you need to focus on the areas that don’t bend as easily, like the thoracic spine, to avoid over-doing the lower back. In addition, it is critical to reduce lower back compression by making sure that the hip flexors are open and flexible enough so that the pelvis is free to move in a way that doesn’t over-compress the lumbar spine.

The work of backbends often starts in simple backbends like upward facing dog, not just deeper backbends like wheel (urdhva dhanurasana). And speaking of upward facing dog, this is a common posture where low back pain or pressure comes up for students. As I discuss in previous articles, when the distance between hands and feet is too short, it can shorten the low back and cause tension or pain. Similarly, over-squeezing glute max can shorten the low back and likewise create tension there or even pain.