Spinal Flexion

Bending the spine has long been associated with back injuries. The idea is that if you bend your back often enough, and particularly under load, the discs between the vertebrae will herniate or bulge such that a nerve gets compressed and pain develops. Flexing your spine under heavy load is most likely not ideal, and can certainly have consequences, however it is not a hard and fast rule. If fact, some world-class powerlifters bend their spine under incredibly heavy loads without injury in the moment. The spine is a resilient structure and requires a more nuanced view when it comes to injury.

https://video.wixstatic.com/video/8817c8_026dd2c07ea349b982ee3ba2c9263047/1080p/mp4/file.mp4

Looking from behind, a view of the spine bending (flexing) forward.

Let’s back up a bit and start near the beginning. Upon learning how to walk, at approximately one year of age, our neck and lower back develop an arch. The curves in these locations are thought to promote stability and control, allowing us to walk on two legs without falling. If you need a visual, think about sticking your butt out as far as you can, that’s the curve of the lower back accentuating and the neck has the same shape. The traditional understanding is that by reversing that curve too often and especially under load, we increase the risk of an injury. Discs tend to herniate in the backward direction and bending the spine might encourage that migration, hence avoiding bending forward. However, it might be that we have spent an inordinate amount of time in the extended spinal position, the one we developed as small children. That has caused structural changes that are no longer amenable to flexion or bending. Once bending is then initiated, a problem might develop.

The difficult part is distribution. We all find movement strategies that are effective, and over time we stick with those strategies and lose the ability to employee others when needed.

If the spine is accustomed to being straight or arched, and we attempt to bend that arch, but a limited number of vertebrae contribute to that movement we might find ourselves in a situation where high pressure develops in one small spot. This could show up in the form of a herniated disc at L4-5 (the most common level to do so). However, if we can move in a way that distributes that pressure more effectively by sharing the load amongst the entire vertebral column the risk of injury most likely diminishes substantially.

The difficult part is distribution. We all find movement strategies that are effective, and over time we stick with those strategies and lose the ability to employee others when needed. If our arched lower back has lost the ability to bend at all levels, pain can develop and movement options might need to be restored. Exercises classified as mobility work, single arm and single leg fitness activities could be useful to restore options or at times a form of manual therapy might be needed. The spine is resilient, and although it has vulnerabilities, we are almost always capable of making changes and improving our capabilities.

Austin Ulrich, Physical Therapist