Lumbar Flexion While Lifting

“Don’t round your back when you lift” is a piece of advice that is almost universal in gyms and physical therapy clinics throughout the world. In fact, this piece of advice is so common that it has basically become universal, and almost seems like a law when it comes to lifting. The most common argument against lifting in this manner is that it places our low backs in a vulnerable position, and makes it much more likely that we will sustain an injury such as a disc bulge or disc herniation, and wind up with low back pain. But the question is….is it actually dangerous to round your back when you lift? 

Where Did This Advice Come From?

There are likely a few different sources for this piece of advice, both from the training/performance world and from the healthcare/research world. It is likely that the advice to avoid lifting with a rounded (ie flexed) spine largely comes from biomechanical research that looks at mechanisms of injury with spinal movement.

In this field of research, repeated loaded flexion (and flexion coupled with rotation) has been shown to be a potential mechanism of disc injury. There is also data to suggest that the compressive strength of our spines are greater in neutral positions. What this means is that it is ultimately easier to cause a disc herniation when going through cycles of spinal flexion, or loaded spinal flexion, than it is when the spine is compressed in a neutral position.

But does that mean that we need to be worried about rounding our backs when lifting?

Issues With This Research

While the previously mentioned research was well done, there are certainly some issues with taking the findings from those studies and extrapolating them to lifters.

The first limitation of these studies is that they are often done with porcine models (ie dead pig spines). Using pig spines is actually a good method to do this research as many characteristics of pig spines are similar to our spines, but since they are cadaver (ie dead) models, they don’t have the ability to adapt to stress as our spines do (since we are, luckily, living). It has been shown that, just like our muscles and other parts of our bodies, our spines have the capacity to adapt to the stress that we place upon them. That means that they can grow stronger and more resilient when challenged, and aren’t prone to “wear and tear” from stress as cadaver spines are.

The second limitation is that when these studies are performed, the spine models are often put through many cycles of flexion and extension, often upwards of 85,000 cycles! This is fairly unlike what we do with our bodies when we are lifting. During any given workout we will often do several sets of squats, deadlifts, or other movements that involve our backs, but these sets are done with relatively few reps per set, and we have rest periods between sets and between training sessions. We aren’t sitting there bending our backs for 85,000 reps all at once.

Lastly, there is evidence that shows that staying in the “neutral zone” isn’t protective from other types of spine injuries, such as end plate fractures. The research primarily shows that loaded spine flexion is a mechanism of injury for disc herniations, which have been shown to typically account for about 2-5% of all back pain cases.

Spinal Flexion May Be Unavoidable

Next, we have to address the elephant in the room, and that is that lumbar spine flexion (rounding our backs) when we are lifting is basically unavoidable. Research has shown that, even when our backs look like they are in a neutral position, they can be undergoing fairly significant amounts of flexion/bending.

If something is basically unavoidable when we lift, should we fear it that much?

Our Take On Spinal Flexion While Lifting

With all of this data and information, loaded spinal flexion is still a tricky topic to navigate. While we argue that you should try to limit low back rounding while lifting in order to lift more efficiently and ultimately perform to a higher degree, we don’t believe that it is something that should be feared, and we certainly don’t think that you should stop a rep/set the moment you notice your back rounding a little bit.

When we are lifting, or doing any other athletic task, how we do that task (ie our movement/technique) will affect how and where the stress/load is placed upon the different parts of the body. 

If how you are lifting places stress on the different parts of your body in a way that you are prepared to handle, then it’s probably no big deal at all! This is often seen in people who almost always demonstrate some noticeable low back rounding while they lift. They seem like they can always lift this way without getting hurt because it’s how they’ve always lifted, which means they are ready to lift that way.

However, if you never find yourself rounding your back as you lift, and then you suddenly find yourself with a lot of low back rounding (such as if you’re going for a new deadlift PR) that you’re not ready to handle, then you might develop an injury/pain. However, we are not very good at predicting when injuries are going to happen, and it is possibly just as likely that you won’t develop an injury/pain in this situation.

Injuries and pain are complex topics, with many factors contributing to them, such as sleep, nutrition, beliefs around injuries, training load/volume, and many others. Our lifting technique is simply one part of this puzzle, and is likely a somewhat small piece when it comes to injuries and pain.

Dealing with low back pain and not sure what to do? Click the button below to request a free phone consult with our team to see if we can help you out!


Ryan VanNieuwenhuyze

Barbell Physical Therapy & Performance

"We Help Active Adults, Lifters, And Athletes Solve Their Pain And Get Back To The Workouts And Sports They Enjoy Without Medication, Surgery, Or Stopping The Activities They Love."