This is something I see all the time on social media: A well-intentioned but under-informed fitness content creator on TikTok or Instagram or YouTube Shorts demonstrating a Romanian deadlift (RDL) and calling it a stiff-leg deadlift (SLDL).

Or the other way around. Or, worse yet, saying they’re interchangeable. They aren’t. Sure, there are bigger fish to fry in the crockpot of online fitness education, but for now, let’s settle something simple: The RDL and SLDL are not the same exercise, nor should you use them for the same purpose.

What Is an RDL?

First, a brief history lesson. Scientists discovered human remains in the Pestera cu Oase (unexpected translation; “Cave With Bones”), (1) a site in modern-day Romania — evidence that there was human activity in Europe almost 40,000 years ago. Then a bunch of other stuff happened, and in 1963, Nicu Vlad was born.

Vlad went on to win gold for Romania at the 1984 Olympics in weightlifting. He was once observed performing a then-foreign accessory exercise that would come to be known as a Romanian deadlift. Now we’re all doing them.

In a sentence, the RDL involves beginning from a standing position with a weight or weights in hand, hinging at the hips to stretch the posterior chain, and standing back up again.

[Related: The Best Lifting Straps for RDLs, SLDLs, & More]

The defining feature of an RDL is that you start the movement standing up; this allows you to play to your strengths by beginning with the exercise’s eccentric (or lowering) phase, where most people are strongest. (2) When you hit the bottom, you get a bit of a force production “bump” from the elasticity of your posterior chain, which helps you start stringing reps together.

Whether you’re an Olympic lifter or not, RDLs are a phenomenal exercise for your hamstrings, glutes, and lower back. They’re accessible, simple to perform, and easy to customize. Top marks, Mr. Vlad.

Okay, Then What’s an SLDL?

The most annoying person in the world might wag a finger and say that, well, an RDL is technically a stiff-leg deadlift, since you’re standing up, weight in hand, with mostly stiff legs. Fair play.

However, understanding exercise nomenclature can help you grasp the idea behind the SLDL itself. Generally speaking, we modify exercise names by putting any technical adjustments first:

That’s, mostly, all there is to it. A stiff-leg deadlift is simply that; deadlifting with your knees stiffer (as in, straighter) than you normally would, and often a bit straighter than you’d see during the RDL, depending on your body proportions.

Deadlifting with straighter legs and higher hips compromises your leverage, reducing the contribution from your quadriceps and shifting more load onto your hamstrings, glutes, and especially your lower back.

However, the primary difference is that SLDLs start with the weight on the floor. Whether you perform a controlled eccentric phase afterward to lower the bar back down, or simply let gravity take the wheel, is up to you. It depends on what you’re trying to get out of the exercise in the first place.

Bodybuilders will perform controlled SLDLs, sometimes even standing on weight plates, because the movement is a second-to-none compound exercise for the hamstrings that doesn’t require you to lift extremely heavy.

[Related: Stop Doing Deadlifts if You Want To Build Muscle]

Strength athletes like powerlifters will employ SLDLs as well, often to deliberately strengthen their lower backs, to train power production off the floor, or simply to inject a bit of welcome variety into an otherwise repetitive sport.

All Roads Lead to Ro…Mania

In fairness, the RDL and SLDL are far more alike than they are different. Both movements train the hamstrings, glutes, and lower back. Both movements are typically, but not exclusively, performed with a barbell. Both movements are worth doing from time to time, whether you’re trying to increase strength or just bulk up.

So why the pedantic semantics? Is it really that big a deal if people mix up the Romanian and stiff-leg deadlift? Yes, because we live in a society, and exercise names matter. Beginners have enough trouble discerning legitimate fitness advice on the Internet.

Understanding the impact small biomechanical changes can have on the performance or utility of an exercise can help you assess other movements, or even entire programs, more shrewdly. Fitness is confusing enough nowadays. The least we can do is get on the same page about what our favorite glute exercises are called.

[Related: How To Build Your Own Bodybuilding Workout Plan]

Overall, though, you aren’t going to find yourself in gym jail if you mix up the two movements or call one the other from time to time. You’re on the right track as long as you’re lifting weights. We’ll all end up like those folks in the Cave With Bones eventually, anyway.

References

1. Trinkaus, E., Milota, S., Rodrigo, R., Mircea, G., & Moldovan, O. (2003). Early modern human cranial remains from the Peştera cu Oase, Romania. Journal of human evolution, 45(3), 245–253.
2. HOLLANDER, DANIEL B.1; KRAEMER, ROBERT R.1; KILPATRICK, MARCUS W.2; RAMADAN, ZAID G.1; REEVES, GREG V.1; FRANCOIS, MICHELLE1; HEBERT, EDWARD P.1; TRYNIECKI, JAMES L.1. MAXIMAL ECCENTRIC AND CONCENTRIC STRENGTH DISCREPANCIES BETWEEN YOUNG MEN AND WOMEN FOR DYNAMIC RESISTANCE EXERCISE. Journal of Strength and Conditioning Research 21(1):p 37-40, February 2007.