You’ve probably heard it hundreds of times: “Don’t lift with your back, use your legs”
Generally, this well intentioned piece of advice involves instructing someone to keep their back straight and lift with their legs, so that they can reduce their risk of injury to their low back. Sounds good and seems logical… except it’s not true.
If your back freshly started hurting recently when lifting with your back, then it’s a smart move to give it time to calm down and find other ways of lifting things, like squatting or kneeling, until things calm down and you are ready to expose yourself to lifting with your back again.
But the advice of lifting with a neutral spine and using your legs holds no water for injury prevention. A recent study from 2021 by Von Arx et al. compared freestyle, stoop (lifting with your back) and squat lifting. Compared to the other styles, “stoop lifting showed significantly lower compressive and total loads” to the spine (Von Arx et al., 2021).
So where does this idea come from? Older studies from the late 90s and early 2000s were done that showed that repeated loaded lumbar flexion + rotation (i.e. lifting with a round and twisted spine) was the best way to herniate a lumbar disc… This information was taken and spread as gospel, and everyone was made to fear rounding their backs for fear of herniating their discs. A fear that still persists to this day amongst many if not most people, including health professionals (unfortunately). There are, however, major problems with these studies. They involved using machines to repeatedly load pig spines in vitro. So what these studies showed was that repeatedly loading a spine thousands of times in bending and twisting would cause the discs to herniate. The major problems with this are:
You cannot extrapolate in vitro data to in vivo and take it as fact (you can’t take a study done on a dead pig spine and extrapolate it to humans).
Lifting in a gym or work setting is never done thousands of times in one sitting, you may do a few to maybe dozens of bending motions a day depending on your sport or job, but not thousands
Pigs are not humans, pigs are quadruped, we are biped, so we should’ve taken that info with a huge grain of salt.
But most importantly
A fundamental principle of human physiology and strength training was completely ignored: Specific Adaptation to Imposed Demand (S.A.I.D.). The human body adapts to load over time and tissues get stronger in response to specific demands. If you use your biceps over and over and over, they get bigger and stronger. This doesn’t only apply to muscles, but bones, ligaments, tendons, and other tissues as well. Your bones get denser, your ligaments get thicker, your discs become more resilient. The spines used for the study were dead, isolated from the body they once belonged to, meaning that even if they were given a chance to recover, they never would’ve adapted to the load, they would have to be live tissue to do that.
So yeah, if you are dead and you somehow manage to deadlift 1000+ reps in a workout while dead, I completely agree, that would be terrible for your spine. But if you are like most people, and are very much alive, and train on a regular basis, or if your job is physically demanding and involves bending and picking things up, so long as you aren’t currently in pain, you are not damaging your back. Even if you lift with a round back. In fact, lifting with a slightly round back has been proven to possibly be the stronger, more efficient position for most people (Mawston et al., 2021), and even when you try to lift with a straight back (which is a perfectly acceptable position by the way), research has shown that your lumbar spine is still flexing between 50-80% of its max in some cases (Lehman, 2018).
Am I trying to say you have to and should round your back? Not at all.
What I am trying to say is that there is no evidence that any particular way of lifting is more likely to cause you an injury than any other position. The best thing you can do is assure the load is appropriate to your skill level, as well as practicing and training many different ways to lift to help avoid fatigue. So get good and comfortable at squatting, deadlifting, lunging, bending, stooping, etc with a straight back, a round back, a twisted back, etc. Next time you see a video of someone deadlifting 500lbs and their back is slightly rounded, instead of cringing, remember that for many people that is likely the most efficient way for them to lift.
Greg Lehman. (2018, April 2). Reconciling Spinal Flexion and pain: We are all doomed to failure but perhaps it doesn't matter. Greg Lehman. Retrieved March 25, 2022, from http://www.greglehman.ca/blog/2018/4/2/reconciling-spinal-flexion-and-pain-we-are-all-doomed-to-failure-but-perhaps-it-doesnt-matter
Mawston G, Holder L, O'Sullivan P, Boocock M. Flexed lumbar spine postures are associated with greater strength and efficiency than lordotic postures during a maximal lift in pain-free individuals. Gait Posture. 2021 May;86:245-250. doi: 10.1016/j.gaitpost.2021.02.029. Epub 2021 Mar 1. PMID: 33799053.
Von Arx M, Liechti M, Connolly L, Bangerter C, Meier ML, Schmid S. From Stoop to Squat: A Comprehensive Analysis of Lumbar Loading Among Different Lifting Styles. Front Bioeng Biotechnol. 2021 Nov 4;9:769117. doi: 10.3389/fbioe.2021.769117. PMID: 34805121; PMCID: PMC8599159.
Washmuth NB, McAfee AD, Bickel CS. Lifting Techniques: Why Are We Not Using Evidence To Optimize Movement? Int J Sports Phys Ther. 2022 Jan 1;17(1):104-110. doi: 10.26603/001c.30023. PMID: 35024210; PMCID: PMC8720246.