Stiff Legged Deadlift (SLDL): How to Do It, Muscles Worked and RDL Differences

A stiff legged deadlift (SLDL) is a hip hinge where you keep your knees nearly straight, with only a soft fixed bend, and lower a barbell or pair of dumbbells towards the floor by pushing your hips back. Because the knees barely move, your hamstrings, glutes and spinal erectors do almost all the work of standing back up. It sits between the Romanian deadlift and a straight-legged good morning in feel, and it's one of the most direct ways to load the hamstrings in a long, stretched position.

Stiff legged deadlift vs Romanian deadlift vs conventional deadlift

All three are deadlifts, but the knee angle changes which muscles carry the load and how far you can go before your back has to give. The table sums up the practical differences.

	Stiff legged deadlift	Romanian deadlift	Conventional deadlift
Knee bend	Slight and fixed (roughly 10 to 15 degrees)	Moderate, more bend as hips go back	Large; knees bend and straighten through the lift
Start position	Often from the floor, or from standing	From standing (top down)	From the floor every rep
Bar path	Can drift a little in front of the shins	Stays in contact with thighs and shins	Close to the legs throughout
Usual range	To mid-shin or the floor, flexibility permitting	To just below the knee or mid-shin	Floor to lockout
Main movers	Hamstrings, glutes, erectors	Hamstrings, glutes	Quads, glutes, hamstrings, erectors
Typical load	Light to moderate	Moderate	Heaviest

The short version: the conventional deadlift is a full-body strength lift, the RDL is a hamstring-focused hinge with a little more knee bend, and the SLDL straightens the legs further so the hamstrings get pulled to a longer length. That longer stretch is the whole point of the stiff legged version, and also why it demands more flexibility and lighter weights.

How to do a stiff legged deadlift

A barbell is the classic way to do it, but the cues below work the same with dumbbells. Start with an empty bar or light plates until the hinge feels natural.

1. Set up. Stand with your feet about hip-width apart, toes pointing forward or slightly out. Hold the bar with an overhand grip just outside your thighs, arms straight.
2. Fix your knees. Unlock them into a slight bend and keep that angle for the whole rep. They shouldn't bend further as you lower, which is the main thing that separates this from an RDL.
3. Brace. Breathe into your belly, tighten your abs and pull your shoulders slightly back and down so your upper back is set. Your spine should stay in the same neutral position from top to bottom.
4. Hinge. Push your hips straight back and let your torso tip forward. The bar travels down in front of your legs. Keep your neck in line with your back, eyes on the floor a metre or so ahead.
5. Find your bottom position. Lower until you feel a strong stretch in your hamstrings or until your back is about to round, whichever comes first. For many people that's mid-shin; flexible lifters can reach the floor.
6. Stand up. Drive your hips forward and squeeze your glutes to return to standing. Don't lean back at the top, just stand tall.

Muscles worked

The SLDL is a posterior chain exercise. Your hamstrings (biceps femoris, semitendinosus and semimembranosus) work as hip extensors under a heavy stretch, your glute max helps drive the hips through, and your erector spinae work isometrically to stop your back rounding. Your forearms and upper back get some work from holding the bar.

The research on deadlift variants is useful here, if a little narrower than people assume. A 2020 systematic review of deadlift EMG studies found that the erector spinae and quads tend to show more activation than the glutes and biceps femoris across deadlift variants, while the Romanian deadlift showed lower erector activity than hamstring activity. It also found that semitendinosus activation generally edges out biceps femoris within the hamstrings.

A 2022 study comparing the Romanian, step-Romanian and stiff-leg deadlift in ten experienced bodybuilders at 80% of their one-rep max is the most direct comparison available. On the lifting phase, the stiff-leg deadlift produced more glute max activity than the RDL, while the RDL produced more semitendinosus activity than the SLDL. Standing on a step to lengthen the range lifted activity across most posterior chain muscles. It's a small sample, so treat it as a pointer rather than a rule, but it suggests the SLDL isn't automatically "more hamstrings" than an RDL; the two load the back of your legs slightly differently.

For a wider set of options, our guide to hamstring exercises covers curls and Nordics that hit the knee-flexing role the SLDL misses.

Sets, reps and load

Stiff legged deadlifts respond best to moderate reps and controlled lowering. Heavy singles aren't the goal, because the straight-knee position limits how much you can lift safely and your lower back tends to fail before your hamstrings do.

• Hypertrophy: 3 to 4 sets of 8 to 12 reps, taking 2 to 3 seconds on the way down. Rest 90 seconds to 2 minutes.
• Strength accessory: 3 sets of 5 to 8 reps after your main squat or deadlift work, with a load you could lift for 2 or 3 more reps.
• Beginners: 2 to 3 sets of 10 with an empty bar or light dumbbells, practising the hinge and range before adding weight.

As a starting point, try roughly 40% to 50% of your conventional deadlift max and build up in 2.5kg to 5kg jumps. Once a week is plenty if you're also deadlifting; twice a week works if this is your main hinge. The NHS recommends muscle-strengthening activity on at least two days a week working all the major muscle groups, and an SLDL covers the back of the legs nicely within that.

If you're training at home, you'll need a decent bar and some plates. Our pick of the best barbells in the UK and best weight plates cover what's worth buying, and the home gym hub has the rest.

Common mistakes

Rounding the lower back to chase depth. The most common one by a distance. Touching the floor means nothing if your spine has to flex to get there; stop at the point where your back stays flat, even if that's just below the knee.

Bending the knees as you lower. It feels easier because it shortens the hamstrings, but then you're doing an RDL. Set the knee angle at the top and hold it.

Locking the knees completely. The opposite problem. Hyperextended knees make the stretch harsher on the joint and the back of the knee, without adding anything useful.

Letting the bar float too far forward. A small drift is normal on the SLDL, but if the bar ends up 20cm in front of your shins, the lever arm on your lower back grows quickly. Keep your lats tight and the bar close.

Going too heavy. People load it like a deadlift and then grind out reps with a round back. Leave the ego plates on the rack.

Hyperextending at the top. Leaning back to "finish" the rep compresses the lower back. Squeeze your glutes and stand straight instead.

Variations

Dumbbell stiff legged deadlift. The most accessible version and a good fit for home training. The dumbbells can travel down the sides or front of your legs, and dropping them is less dramatic than dumping a loaded bar. The setup and grip details are much the same as the dumbbell deadlift.

Single-leg stiff legged deadlift. Hinge on one leg while the other extends behind you. It's far lighter, much harder on balance, and good for spotting a left-right imbalance. Our single-leg deadlift guide walks through the balance cues.

Deficit stiff legged deadlift. Stand on a low step or a weight plate so the bar or dumbbells can travel further below your feet. This adds range and stretch, which fits the step-RDL findings above, but only flexible lifters with good spinal control should try it. The general principles are the same as a deficit deadlift.

Kettlebell or band version. A single heavy kettlebell between the feet, or a band anchored under your feet, both work for higher-rep finishers when you don't own a barbell.

Who should avoid it or regress

The SLDL isn't for everyone on day one. Skip it or scale it back if you:

• Have a current lower back injury or disc problem. Get the go-ahead from a physio first, because the straight-leg position puts more load through the lumbar spine than most hinges.
• Can't touch below your knees with a flat back. Your hamstring flexibility is the limiter. Start with a Romanian deadlift, a hamstring stretching routine and a shorter range.
• Are new to lifting. Learn the hinge first with a kettlebell deadlift or RDL, then move to the stiffer-legged version once you can hold a neutral spine under load.

If none of the variations suit you, our Romanian deadlift alternatives list several hip hinges and hamstring moves that are easier on the back.

Recommended reads

• Romanian deadlift: how to do it and muscles worked
• Deadlift: form guide and common mistakes
• Romanian deadlift alternatives
• Dumbbell deadlift guide
• The best barbells in the UK