Forward bends can be quite problematic for the lower back, because overly rounding (flexing) the back is probably the most common way in which people sustain lower back injuries. While we often don’t know what actually gets injured when we hurt our lower back, one common injury is the bulging or rupture of an intervertebral disc towards the rear and usually slightly to one side when its front edge is compressed too strongly. Why is that an issue? When a disc bulges or ruptures it can compress a nerve root exiting the spinal cord, triggering significant and even debilitating pain.

While the spinal cord, which lies behind the discs, is relatively well protected from disc herniation by a long tough ligament called the posterior longitudinal ligament, this ligament is by necessity narrow, which means that the nerves exiting sideways from the spinal cord are not protected by it. When a disc bulges or ruptures to the rear and one side (because the longitudinal ligament usually prevents it from bulging straight back), it can impinge on a nerve root and thus trigger the pain.

The majority of disc herniations occur between the two lowest lumbar vertebrae (L4-L5) or between the lowest lumbar vertebra and the sacrum (L5-S1). A herniated disc is also commonly referred to as a slipped disc, but this is a misnomer as the discs cannot slip, being tightly connected to the vertebral bodies above and below. A ruptured or herniated disc is a more severe injury than a bulging disc, in which the tough outer layer of the disc (the annulus fibrosus) remains partially intact. The majority of disc herniations heal within weeks, and very few require surgery, but nonetheless we are better off not injuring them in the first place, and sometimes the pain can become chronic.

So what can you do to keep your lower back safe in forward bends? Four things: stop following the path of least resistance, stretch your hamstrings in poses that make it impossible to bend the back instead, lengthen the spine when you bend forward, and practice with appropriate intensity.

1. Stop following the path of least resistance

When we move unconsciously, we use our strong muscles to move our flexible joints, and we avoid using weak muscles to move tight joints. Part of the reason for this is that it requires less mental effort to repeat the same movement patterns over and over rather than create new ones, and part of it is that we avoid expending unnecessary physical energy. Both reasons are related to the fact that evolutionarily speaking, we are built for efficiency. But efficiency, while it may help prevent early death from starvation, does not necessarily increase balance, well-being, or happiness, and does not help prevent injuries.

Desikachar used to say “make your practice smarter than your habits”, and this sentiment applies perfectly to forward bends. Forward bends are designed to flex your hips and your entire spine, but because of the strength and tightness of most people’s hips and hamstrings, when we bend forward we tend to do too much of the bending in the lower back, and not enough in the hip joints, and as a result, the hip joints get ever tighter as we grow older. We avoid moving the hips because stretching big, tight joints and muscles requires both mental and physical effort, and we’d rather not be bothered. But as a result of tight hips, we predispose ourselves to overwork the lower back and injure it. The result is that 80% of Americans complain of lower back pain, making it the number one health complaint in the US.

Don’t believe me that you are avoiding moving your hip joints even in very easy movements? Try this simple hip flexing exercise: Lie on the floor and notice that your lower back is not actually in contact with the floor. Inhale one knee towards the chest in a simple hip flexion movement, and hold your shin with your hands. Notice what has happened to your lower back. It is now in contact with the floor, even though you had no idea that you flexed your spine when you flexed your hip. Even in this exceedingly gently hip flexion (after all, the hamstrings aren’t even involved because the knee is also flexed, and the hamstrings span both joints), we do as much of the work as we can in the lumbar spine, rather than the hip joints. No longer following the path of least resistance in forward bends means doing more hip flexion, and less lumbar spine flexion. In Anusara yoga, the movement that shifts the work of forward bends out of the lower back is called Inner Spiral. In anatomy terminology, it’s referred to as anterior hip tilt, meaning moving the tops of the hips forward towards the knees.

2. Stretch your hamstrings in poses that make it impossible to bend the back instead

If your hamstrings are seriously tight, just building awareness of your unbalanced movement patterns may not be enough, because the muscles you use to move your hips back towards neutral (primarily the iliopsoas) may not be strong enough to overcome super tight hamstrings. And in the process of trying to stretch your hamstrings in order to help out your lower back, you may actually injure your lower back! Not so useful.

The solution is to stretch your hips and hamstrings in poses that don’t allow you to move the intensity elsewhere. Simply put, this means reclining hip openers, because when you lie on your back and flex your hips, you can only flex your lower back a few degrees before it flattens against the floor and can go no farther. Being pressed against the floor also means that your lower back is perfectly safe here, unlike in seated or standing forward bends. In fact, if you are limited to less than 90 degrees of hip flexion in Supta Padangusthasana (reclining straight-legged hamstring stretch), then I would suggest avoiding standing and seated forward bends entirely for the time being, or at least dialing the intensity way back.

Most of us do suffer from tight hamstrings, but fortunately lengthening muscles is relatively straightforward, and results can be seen within a matter of weeks if you are consistent in your exercises, emphasize surrender in your stretches, and practice with perfect intensity.

3. Lengthen the spine when you bend forward

Keeping the spine long helps protect the back in forward bends as well as in backbends, because the more the front edge of the disc is compressed, the greater the internal disc pressure, which is the direct cause of herniating discs (the pressure can rise from 17psi in a lumbar disc in a reclining person to over 300psi when lifting a heavy object with a rounded lumbar spine). Keeping the spine long maintains more space between the vertebrae, thus reducing pressure inside the discs. How do you keep the spine long in forward bends? One instruction for seated forward bends I give is to think of the movement as lifting up and over, rather than bending down. To make this concept more visceral I use the image of a cresting and crashing wave. If you have ever watched a crashing wave closely, you may have noticed how the water actually runs UP the front surface of the wave before crashing forward and down. Turning the forward bend into an act of “lifting up and over” instead of pulling yourself down quite naturally lengthens the spine and helps protect it.

4. Practice with appropriate intensity

The final point I want to emphasize for safe forward bends here is that forward bends are considered cooling, down-regulating poses, designed to increase your capacity to relax and surrender. While seated forward bends are considered some of the most basic yoga poses and are included in most beginner’s syllabi, they have great potential for causing injury when done with poor alignment and with too much effort. Straight legged versions are particularly problematic because the straight leg position pulls the hamstrings tight, which in most people limits hip rotation even more than bent-knee seated poses. The other reason why straight-legged seated forward bends are particularly dangerous is that many people are too concerned with the ego-gratifying but essentially meaningless detail of reaching their feet with their hands in these poses, often tempting them into generating too much stretch intensity. If you approach forward bends the way you do a Warrior I, for example, you are much more likely to injure yourself, and to completely miss the point of forward bends, to boot.