A stiff leg deadlift is a hip-hinge exercise where you lower a weight toward the floor with minimal knee bend, placing the majority of the workload on your hamstrings, glutes, and lower back. It looks similar to a conventional deadlift but starts with higher hips and a nearly vertical shin, and your knees stay only slightly soft throughout the entire movement. It’s one of the most effective exercises for building posterior chain strength and improving hamstring flexibility.
How to Perform a Stiff Leg Deadlift
Stand with your feet about hip width apart and position the barbell over the top of your shoelaces. Your shins should be vertical and your hips roughly the same height as your shoulders, which is noticeably higher than a conventional deadlift setup. Keep your spine neutral from start to finish.
Grip the bar just outside your legs and drive through the whole foot to stand up, extending your hips and knees together. On the way down, push your hips back while keeping your knees only slightly bent. The bar should track in a straight vertical line, staying close to your body the entire time. If the bar drifts forward even a few inches, the load shifts to your lower back in a way that reduces hamstring engagement and increases injury risk.
You’ll naturally feel your weight shift toward your heels as you hinge. That’s normal, but don’t let it become so aggressive that your toes lift off the ground. Think about maintaining three points of contact with the floor: big toe, little toe, and heel. Lower the bar until you feel a strong stretch in your hamstrings, then drive your hips forward to return to standing.
Muscles Worked
The primary targets are your hamstrings, glutes, and erector spinae (the muscles running along your spine). Because the knees stay nearly straight, the hamstrings are stretched under load through a longer range of motion than most other deadlift variations. Your lower back muscles work hard to keep your spine from rounding, and your glutes power the hip extension at the top of each rep. If you use a wide, snatch-style grip, your lats also become a significant contributor.
The limited knee bend is what makes this exercise distinct. Less knee flexion means your quads contribute very little, so the posterior chain handles almost all of the work. That makes the stiff leg deadlift closer to an isolation exercise for the back of your body than a full-body pull like a conventional deadlift.
Stiff Leg Deadlift vs. Romanian Deadlift
These two exercises get confused constantly, and the difference comes down to one thing: how much your knees bend. A Romanian deadlift allows more knee flexion, creating a smaller angle between your hamstrings and calves at the bottom. Your butt pushes further back, and the emphasis shifts slightly more toward the glutes.
In a stiff leg deadlift, knee bend is minimal. Your hips stay more forward, and the hamstrings and lower back take on a greater share of the load. The reduced knee flexion also means your lower back works harder to maintain position, which is both a benefit (stronger erectors) and a risk if your form breaks down. If you’re newer to hip-hinge movements, the Romanian deadlift is generally more forgiving because the extra knee bend takes some pressure off the lumbar spine.
Why Lower Back Safety Matters Here
Heavy deadlift variations can produce compressive spinal loads between 5 and 18 kilonewtons, with shearing forces between 1.3 and 3.2 kilonewtons. Those are significant numbers, and the stiff leg version places more of that demand on the lower back compared to variations with greater knee bend.
Fatigue makes this worse. Research on repetitive lifting shows that as a set drags on, your spine gradually rounds without you noticing. In one study, lumbosacral flexion increased from about 72% of maximum range to over 98% by the final minute of a lifting-to-failure protocol. In practical terms, your lower back creeps closer and closer to its structural limit as you fatigue. This is why controlling your rep count and avoiding true failure on stiff leg deadlifts is more important than on many other exercises.
The biggest red flag during the movement is the bar tracing an “S” shape rather than a straight vertical path. That S-pattern means there’s slack in the system, meaning you’ve lost tension somewhere and your joints are absorbing force they shouldn’t be. Keep the bar close, brace your core before each rep, and stop the set when your back starts to round.
Common Form Mistakes
The most frequent error is turning this into a squat. If your hips drop low and your knees push forward, your quads take over and you lose the hamstring emphasis that makes this exercise worth doing. Your shins should stay close to vertical throughout.
The opposite mistake is letting your hips shoot up too fast on the way up. When that happens, your legs straighten before your torso rises, dumping the entire load onto your lower back. The fix is to think about your hips and shoulders rising at the same rate.
Letting the bar drift away from your body is the third major issue. Even a small gap between the bar and your legs creates a longer lever arm that multiplies the force on your spine. The bar should practically graze your shins and thighs on every rep.
Barbell vs. Dumbbell Variations
A barbell lets you load the movement heavier, which makes it the better choice for building maximum strength and driving muscle growth over time. The fixed bar path also simplifies the movement pattern.
Dumbbells offer a greater range of motion since there’s no bar hitting your shins at the bottom. They also force each side of your body to work independently, which helps identify and correct strength imbalances between your left and right sides. The tradeoff is that your grip will give out before your hamstrings do once the dumbbells get heavy enough, and most gyms don’t stock dumbbells heavy enough for advanced lifters to get a real training stimulus.
For most people, starting with dumbbells to learn the hip-hinge pattern and then progressing to a barbell for heavier loading is a practical approach.
Sets, Reps, and Programming
For muscle growth, 3 to 4 sets of 7 to 12 reps is the range most lifters respond well to. Aim for around 25 to 35 total reps per session. Because the stiff leg deadlift is taxing on the lower back and central nervous system, it accumulates more fatigue per set than many other exercises. Keeping reps at 12 or below helps you maintain form through the end of each set, which matters more here than on less technically demanding movements.
If your goal is pure strength, sets of 3 to 5 reps with heavier loads work, though most lifters will get better results from the moderate rep range unless they’ve already built a strong base. Leave at least one rep in reserve on every set. Going to true failure on a movement that loads the spine this heavily isn’t worth the risk, especially as fatigue increases lumbar flexion in ways you can’t always feel in the moment.
Placing the stiff leg deadlift early in your workout, when you’re fresh, gives you the best chance of maintaining clean technique through all your sets. Pairing it later in a session with other heavy posterior chain work is a recipe for the kind of fatigue-driven form breakdown that leads to back tweaks.