RDL vs. Stiff Leg vs. Conventional Deadlift: What’s the Actual Difference?
Walk into almost any strength gym on a Monday or Tuesday, and you’re bound to see someone pulling a barbell off the floor. But if you look closely, you'll notice that not all deadlifts are created equal.
"What is the actual difference between an RDL, a stiff leg, and a regular deadlift?"
It’s one of the most common questions we get on the gym floor at Capital Strength. To the untrained eye, they all look like variations of "picking up heavy stuff and putting it down." And while it’s true that all three movements heavily target your posterior chain (your hamstrings, glutes, and back), subtle tweaks to your hip height and shin angle completely change which muscles do the heavy lifting.
If you want to maximize your strength gains, build a resilient back, and train pain-free, you need to know exactly how and why to use each variation. Let’s break down the mechanics.
1. The Romanian Deadlift (RDL): The Top-Down Hinge
The biggest differentiator of the Romanian Deadlift is where the movement starts. Unlike most deadlifts, the RDL begins from a standing position (the top) rather than from the floor.
The Setup: Stand tall with the barbell in your hands. Soften your knees slightly, lock your shoulder blades down into your back pockets, and focus entirely on pushing your hips straight back toward the wall behind you.
The Mechanics: As you hinge, keep the barbell completely pinned against your thighs and shins. Lower the bar only as far as your hips can travel backward - usually right about knee-height or slightly below. Your shins should remain almost perfectly vertical throughout the entire movement.
Primary Targets: Your hamstrings, glutes, and upper back. Because you maintain constant tension and omit the leg drive from the floor, the RDL is an unparalleled tool for building pure muscle hypertrophy in the glutes and hamstrings.
2. The Stiff Leg Deadlift (SLDL): The Ultimate Hamstring Stretch
The Stiff Leg Deadlift is frequently confused with the RDL, but the execution and intent are entirely different. The SLDL starts completely dead from the floor, just like a conventional deadlift, but it isolates the backside of your body with zero mercy.
The Setup: Walk up to the bar on the floor. Instead of dropping your hips down to pull, you keep your hips high and your shins almost completely vertical.
The Mechanics: With your knees only slightly bent (but not locked out entirely), you pull the bar off the floor using almost pure hip extension. Because your hips start so high, your torso will be nearly parallel to the floor at the start of the lift.
Primary Targets: This variation forces an incredibly intense, deep stretch on the hamstrings and glutes right from the absolute bottom of the movement. It requires excellent hamstring flexibility and a rock-solid core to execute safely.
3. The Conventional Deadlift: The Full-Body Powerhouse
The conventional deadlift is the undisputed king of total-body strength. Unlike the previous two variations, which purposefully isolate the posterior chain, the conventional deadlift is a multi-joint coordination of your entire body.
The Setup: Step up to the barbell on the floor. Unlike the stiff leg variation, you will actively drop your hips lower and allow your shins to angle forward until they touch the bar.
The Mechanics: Because your shins angle forward, your quads can now enter the chat. You begin the movement by dynamically pushing the floor away with your legs to break the bar off the ground, smoothly transitioning into a powerful hip hinge to lock the weight out at the top.
Primary Targets: True full-body integration. Because of the forward shin angle and lower hip placement, you get to distribute the load relatively equally across your quads, glutes, hamstrings, and your entire back. This is why you can pull significantly more weight conventionally than you can with an RDL or SLDL.