Is Weight Lifting with a Rounded Back Safe?
In recent years, there has been an increasing debate in strength and conditioning circles about the safety of lifting with a rounded or flexed lower back. Traditionally, strength and rehab experts have advocated for maintaining a neutral spine position during lifts, arguing that it reduces the risk of injury. But as more professionals in the rehab space challenge this conventional advice, the question arises: Is weight lifting with a rounded back safe? Is it dangerous?
In the above video, I dive into some key studies often cited in these discussions, explain why there isn’t a clear consensus, and share my perspective based on clinical experience and what we know so far.
The Traditional Approach: Neutral Spine Lifting for Safety
For years, coaches and rehab professionals have emphasized keeping a “neutral” spine during lifting movements like squats and deadlifts. Neutral spine means the lower back remains in a relatively straight, stable position, avoiding excessive flexion or extension. This advice has been passed down due to concerns that rounding the lower back (flexion) could place undue strain on spinal discs and soft tissues, potentially leading to injury.
The Research on Spinal Motion During Lifting
A recent study by Assa and colleagues examined how much motion occurs in the spine during squats and deadlifts. The researchers observed that even when lifters aimed to keep a neutral spine, some motion still occurred, especially in the lower lumbar spine. Specifically, they found about 9-12 degrees of movement in the upper lumbar spine and 18-22 degrees in the lower lumbar spine during these lifts. While this isn’t full flexion (around 60-65 degrees for most people), it shows that a bit of spinal motion is natural and expected, even when aiming for a neutral position.
Instead of maintaining a rigidly fixed position, it may be more realistic to think of the spine as working within a “neutral zone”—a range of motion where the spine is safe and stable but not strictly motionless. In this zone, loads may be distributed more evenly across tissues, reducing strain on any one area.
The “To Flex or Not to Flex” Study: Exploring Flexion and Low Back Pain
A study often cited by those arguing for the safety of lifting with a rounded back is a systematic review titled “To Flex or Not to Flex.” This review examined the relationship between lumbar spine flexion (rounded back) and low back pain. Surprisingly, the researchers found no correlation between lifting with a rounded back and developing low back pain. However, there’s a critical caveat: none of the studies they reviewed involved heavy lifting. The weights used in these studies ranged from a light pen to just 26 pounds—not exactly what we see in the gym.
Because of this limitation, we can’t directly apply the study’s findings to lifters who are deadlifting or squatting significant weight. While it does suggest that rounding the back with lighter loads might be safe, it doesn’t address whether lifting heavy with a rounded spine could pose risks.
Clinical Patterns of Low Back Pain when Lifting in Lumbar Flexion
In my clinical experience, lifters who develop low back pain from deadlifting often exhibit two patterns. The first pattern involves lifters who deadlift with excessive lumbar flexion, taking the spine to its end range. These individuals frequently experience “flexion-intolerant” pain, meaning they feel discomfort when bending forward, sitting for long periods, or rounding their back.
The second pattern I see is lifters who are stiff into lumbar flexion, so they inadvertently lift with a rigid spine. These lifters tend to experience pain because they lack adequate range of motion, so when they lift, the heavy loads are pulling them to their end ranges.
Balancing the Neutral Spine with Flexion Tolerance
Based on the available research and my experience, I still advocate for a more neutral spine position during heavy lifts like squats and deadlifts, as long as lifters stay within their natural range and avoid extreme flexion. This approach distributes forces more evenly and prevents overloading specific tissues, which I believe is the safest strategy for heavy lifting. However, I also believe in the value of exposing the spine to some flexion with lighter loads, as life—and even lifting—doesn’t always occur in a perfectly neutral position.
Exercises that train the spine to tolerate different ranges, like Jefferson curls and reverse hypers, help build strength and resilience, preparing lifters for inevitable moments when the spine moves outside a neutral zone.
The Takeaway: An Evolving Approach
As of now, without conclusive research one way or the other, I rely on expert guidance, clinical patterns, and my own observations to inform my coaching and training methods. While my current recommendation is to aim for a neutral spine on heavy lifts, I’m open to changing my approach as more research becomes available.
