The Romanian deadlift and the stiff leg deadlift are two of the most commonly confused exercises in strength training. They look similar, they work similar muscles, and in many gym settings the terms are used interchangeably by coaches and athletes who are not certain of the distinction. But they are genuinely different exercises that produce meaningfully different training stimuli, and choosing the right one for a specific goal matters.
This guide covers the specific technical differences between the two exercises, the distinct training stimuli they produce, and a clear framework for deciding which belongs in your programme and when.
What Each Exercise Is
The Romanian Deadlift
The Romanian deadlift (RDL) is a hip hinge exercise that begins and ends at the standing position. The lifter stands with a load (barbell, dumbbells, or bands) and pushes the hips backward while maintaining a consistent slight bend in the knees, lowering the load along the front of the legs until a hamstring stretch is felt, then drives the hips forward to return to standing.
Defining characteristics:
- Starts from the standing position, not the floor
- Maintains a consistent, slight knee bend throughout (approximately 15 to 20 degrees)
- The knee bend does not change significantly during the movement
- The hips push backward as the primary initiation
- Range of motion is limited by hamstring flexibility and neutral spine maintenance
- The load typically descends to mid-shin level for most people
The Stiff Leg Deadlift
The stiff leg deadlift (SLDL) begins from the floor (like a conventional deadlift) and involves a more significant degree of knee extension than the RDL. The lifter picks the bar from the floor with legs that are relatively straight (though not completely locked), lowers the bar back to the floor with minimal knee bending, and repeats.
Defining characteristics:
- Typically starts from the floor with each repetition
- The knees are relatively straight throughout, often approaching full extension
- The range of motion often extends to the floor
- Greater spinal flexion may occur in the fully extended knee position compared to the RDL
- The load travels all the way to the floor between reps in the standard version
The Key Technical Differences
Knee Position
This is the most fundamental difference between the two exercises and the source of all the meaningful training distinctions that follow.
Romanian deadlift: The knees maintain a consistent 15 to 20 degree bend throughout the movement. This bend reduces the hamstring tension below maximum and allows the hips to push further back, creating a movement that is more hip-dominant and which the hamstrings can control through a larger range before reaching their end-range tension.
Stiff leg deadlift: The knees are kept relatively straight, approaching full extension. This pre-stretches the hamstrings before the movement even begins. As the torso leans forward, the combination of hip flexion and near-complete knee extension places the hamstrings under their maximum possible tension, approaching the end range of the muscle’s length.
The consequence of this difference: The stiff leg deadlift places the hamstrings under significantly more tension and at a longer muscle length than the RDL. This produces greater passive and active tension in the hamstrings throughout the movement. Whether this is advantageous or problematic depends on the goal and the individual’s hamstring flexibility.
Starting Position
Romanian deadlift: Begins and ends at the standing position. The load never touches the floor between reps in the standard version. Each rep is performed as a continuous set from the standing position.
Stiff leg deadlift: Typically begins from the floor, replicating the start position of a conventional deadlift but with straighter knees. The load returns to the floor between reps (or at the end of a set in the Romanian-start stiff leg variation).
Range of Motion
Romanian deadlift: The range is self-limited by hamstring flexibility and neutral spine maintenance. Most people reach a position where the torso is between horizontal and 30 degrees above horizontal before neutral spine is compromised.
Stiff leg deadlift: Because the floor provides a defined endpoint, the range of motion can extend until the load contacts the floor regardless of whether neutral spine is maintained at that depth. For many people, reaching the floor with straight legs requires significant spinal flexion, particularly in the lumbar region.
Spinal Position
Romanian deadlift: The controlled range of motion and the hip push-back mechanism make it more naturally conducive to maintaining neutral spine throughout, because the depth is self-regulated by the lifter.
Stiff leg deadlift: The floor endpoint and the extreme hamstring tension of the near-extended knee position create a greater tendency toward lumbar rounding, particularly as fatigue accumulates. The straight knee position restricts the hamstrings more severely, which pulls the pelvis into posterior tilt and the lumbar spine into flexion at the bottom of the movement.
Muscle Emphasis
Both exercises primarily work the hamstrings and gluteus maximus. The difference is in the relative emphasis:
Romanian deadlift:
- Greater gluteus maximus involvement because the hip push-back creates a larger hip range of motion through which the glutes work
- Hamstrings work through a moderate range with moderate tension
- The return phase is glute-dominant
- More appropriate as a glute development exercise
Stiff leg deadlift:
- Greater hamstring emphasis because the near-extended knee position maximises hamstring tension throughout
- The hamstrings are under greater passive tension at the bottom of the movement due to the combined hip flexion and knee extension
- More appropriate as a hamstring isolation and end-range strengthening exercise
- Greater eccentric hamstring load at long muscle lengths
Which Exercise Is Better For Specific Goals
For Glute Development
Choose the Romanian deadlift.
The RDL’s greater range of hip motion and its emphasis on the hip push-back and hip drive forward produce more comprehensive gluteus maximus loading across a larger range of hip extension. The glutes are the primary drivers of the return phase in the RDL, and the exercise’s resistance curve (greatest challenge when the hips must extend from their pushed-back position) aligns well with the glutes’ strongest range.
For Hamstring Development
Choose the stiff leg deadlift, with caution.
The SLDL’s near-extended knee position maximises the length-tension relationship of the hamstrings and loads them at the longest muscle lengths available. Research on muscle hypertrophy increasingly supports that training muscles at long lengths (the stretched position) may produce greater hypertrophy than training at shorter lengths, making the SLDL’s extreme hamstring stretch potentially advantageous for hamstring muscle development.
The caution: the SLDL’s spinal rounding risk and the extreme hamstring tension it creates (which increases the risk of proximal hamstring tendinopathy and hamstring strain if progressed too aggressively) mean it should be introduced gradually and not used with heavy loads early in a training cycle.
For Athletes and Sport Performance
Choose the Romanian deadlift.
The RDL’s better spinal position, its glute emphasis, and its applicability to heavier loads make it the more practical and more broadly applicable exercise for athletic development. The hip push-back and hip drive mechanics of the RDL also more closely replicate the hip hinge demands of athletic movements (sprint push-off, jump landing, direction change) than the SLDL.
For Maximum Hamstring End-Range Strength
Choose the stiff leg deadlift.
If the specific goal is developing hamstring strength at long muscle lengths, for example for an athlete recovering from a proximal hamstring strain or developing the end-range hamstring strength for a specific sport skill, the SLDL’s extreme hamstring stretch is the more specific exercise.
For Beginners
Choose the Romanian deadlift.
The RDL is significantly easier to learn safely than the SLDL. The self-regulated range of motion means beginners naturally stop at a depth where they can maintain neutral spine. The SLDL’s floor endpoint and extreme hamstring tension create greater spinal rounding risk for people who are learning the hip hinge pattern.
For People With Limited Hamstring Flexibility
Choose the Romanian deadlift.
Limited hamstring flexibility makes the near-extended knee position of the SLDL immediately compromising to spinal position. The RDL’s adjustable range of motion accommodates limited hamstring flexibility by simply reducing the depth to where neutral spine can be maintained.
For Post-Hamstring Strain Rehabilitation
Choose the Romanian deadlift initially, progressing to the stiff leg deadlift.
Early-stage hamstring rehabilitation benefits from the RDL’s moderate hamstring tension and controlled range of motion. As rehabilitation progresses, the SLDL’s greater end-range loading can be introduced to develop the hamstring strength at long muscle lengths that specifically reduces re-strain risk, as this is the length at which hamstring strains most commonly occur.
A Side-by-Side Comparison
Starting position:
Romanian deadlift: Standing
Stiff leg deadlift: Floor or standing
Knee position:
Romanian deadlift: 15 to 20 degrees of flexion throughout
Stiff leg deadlift: Near full extension throughout
Primary muscle emphasis:
Romanian deadlift: Gluteus maximus and hamstrings (more glute-dominant)
Stiff leg deadlift: Hamstrings primarily (more hamstring-dominant)
Hamstring tension:
Romanian deadlift: Moderate to high through mid-range
Stiff leg deadlift: High to very high throughout, especially at the bottom
Spinal rounding risk:
Romanian deadlift: Lower
Stiff leg deadlift: Higher
Appropriate load range:
Romanian deadlift: Can be loaded heavily with good technique
Stiff leg deadlift: Should be loaded more conservatively due to spinal rounding risk
Best for:
Romanian deadlift: Athletes, glute development, general posterior chain strength, beginners
Stiff leg deadlift: Hamstring hypertrophy, end-range hamstring strength, experienced lifters
Range of motion:
Romanian deadlift: Self-limited by flexibility and neutral spine
Stiff leg deadlift: Can extend to the floor
How to Programme Both
Romanian Deadlift Programming
The RDL is appropriate as a primary posterior chain exercise 2 times per week, or as a secondary exercise following conventional deadlifts.
As a primary exercise:
- 3 to 4 sets of 6 to 10 reps at moderate to heavy load
- 2 times per week
- Progressive load increase of 2 to 5 kilograms per session when technique is clean
As a secondary exercise:
- 3 sets of 10 to 12 reps at a moderate load after primary barbell work
- Once per week
Stiff Leg Deadlift Programming
The SLDL is most appropriate as an accessory exercise rather than a primary movement due to the greater spinal rounding risk at heavy loads and the more extreme hamstring tension that limits how hard it can be pushed safely.
As an accessory exercise:
- 3 sets of 8 to 12 reps at a moderate load
- Once per week
- Should not be programmed in the same session as heavy conventional deadlifts due to the cumulative lumbar fatigue
For hamstring hypertrophy emphasis:
- 3 to 4 sets of 10 to 15 reps at a load that produces a deep hamstring stretch without lower back rounding
- Slow eccentric (3 to 4 seconds down) to maximise time under tension at the long hamstring length
Including Both in the Same Programme
Both exercises can coexist in a weekly programme with appropriate scheduling:
Day 1: Primary lower body (conventional deadlift or squat), Romanian deadlift as accessory (3 x 10)
Day 2: Rest or upper body
Day 3: Posterior chain focus: stiff leg deadlift (3 x 12 at moderate load), hip thrust, Nordic hamstring curl
This scheduling separates the RDL and SLDL by 48 hours and avoids stacking them in the same session with heavy conventional deadlifts.
The Most Common Confusion Between the Two
The “stiff leg RDL”: Many people perform what they call a stiff leg deadlift but start from the standing position and never let the bar touch the floor, which is technically an RDL with near-straight legs. This hybrid is a valid exercise that sits between the two on the tension-versus-range spectrum, but it is neither the classic Romanian deadlift nor the classic stiff leg deadlift as described above.
The terminology problem: In many gym settings, Romanian deadlift and stiff leg deadlift are used interchangeably, with some coaches using one term to mean what others call the other. If there is any uncertainty about what is being prescribed, clarify by asking about knee position (bent versus straight) and starting position (standing versus floor).
The overlap zone: There is genuine overlap between the two exercises. The RDL performed with a slightly more extended knee than standard and the SLDL performed with a slight knee bend meet somewhere in the middle. This overlap is why experienced coaches and athletes often modify each exercise’s technique to suit their specific goals rather than adhering strictly to the canonical form of either.
Frequently Asked Questions
Is the stiff leg deadlift harder than the RDL?
Not necessarily harder overall, but harder on the hamstrings and more demanding on spinal position. The extreme hamstring tension of the SLDL makes the hamstrings fatigue faster than in the RDL, but the more limited range of motion and the self-regulated depth of the RDL can make it harder in total volume terms when heavy loads are used. The SLDL is harder to perform with good spinal position, which is the most practically important consideration.
Can I use the same weight for both exercises?
Most people can lift more weight in the RDL than the SLDL because the RDL’s knee bend reduces the hamstring tension and allows a more mechanically efficient movement pattern. When transitioning from RDL to SLDL, reduce the weight by approximately 15 to 25 percent initially to account for the different demands.
Which exercise is safer for the lower back?
The Romanian deadlift is generally safer for the lower back because the self-regulated range of motion prevents the depth-induced spinal flexion that the stiff leg deadlift’s floor endpoint can produce. The RDL also allows heavier loading with better spinal position, making it the more back-friendly choice for most people.
Should beginners do the stiff leg deadlift?
Not as a starting exercise. The near-extended knee position of the SLDL immediately stresses the hamstrings at their longest lengths, which can produce significant soreness in people unaccustomed to this loading, and the spinal rounding risk is greater than in the RDL. Beginners should develop the hip hinge pattern through the RDL before introducing the SLDL.
Which exercise is better for running performance?
The Romanian deadlift is generally the more appropriate choice for runners because it develops both glute and hamstring strength in a mechanically efficient hip hinge pattern that more closely replicates the demands of running push-off mechanics. The stiff leg deadlift’s hamstring end-range loading can be a useful complement for runners recovering from hamstring strain or specifically developing end-range hamstring strength for injury prevention.