Stiff-Leg Deadlift for Hamstring Development: Form Guide

The stiff-leg deadlift is the most hamstring-dominant free weight exercise you can do. It places the hamstrings under an extreme stretch at the bottom of the movement - longer muscle lengths under load, which research shows is the most potent stimulus for muscle growth. But it is also one of the most commonly confused exercises, often mixed up with the Romanian deadlift.

Let me clear up the differences and show you how to do the stiff-leg deadlift properly for maximum hamstring development.

Stiff-Leg Deadlift vs Romanian Deadlift

These two exercises look similar but differ in important ways:

Romanian deadlift: Starts from the top (standing). Hips push back significantly. Knees bend slightly (15-20 degrees). The bar stays very close to the body. Range of motion stops when you feel a hamstring stretch, typically at mid-shin.

Stiff-leg deadlift: Can start from the top or the floor. Legs are kept nearly straight - minimal knee bend. The bar may drift slightly forward. Range of motion goes deeper - the bar may touch the floor or the tops of your feet, depending on flexibility.

The key difference: the stiff-leg version keeps the knees much straighter, which places more stretch on the hamstrings at the bottom and reduces glute involvement compared to the RDL. It is a pure hamstring exercise when done correctly.

How to Perform the Stiff-Leg Deadlift

Starting Position

Stand with feet hip-width apart, holding a barbell in front of you with an overhand grip at shoulder width. Or set up from the floor as you would for a conventional deadlift.

The Descent

With only a very slight bend in your knees - 5 to 10 degrees maximum - hinge at the hips and lower the bar toward the floor. Your legs stay nearly straight throughout.

Let the bar travel in a natural path. Unlike the RDL where you drag the bar down your thighs, the stiff-leg deadlift allows the bar to move slightly forward as you reach toward the floor.

Lower as far as your hamstring flexibility allows. For most people, the bar will reach somewhere between mid-shin and the floor. You should feel an intense stretch in your hamstrings at the bottom position. If you feel it in your lower back instead, your back is rounding - stop at the point where your back starts to round and work on flexibility over time.

The Ascent

Drive your hips forward to return to standing. The movement should come from hip extension powered by the hamstrings. Do not use your lower back to lift the bar - think of your hamstrings pulling your torso upright.

Squeeze your glutes at the top to ensure full hip extension.

The Critical Form Point

Your lower back must stay flat - or as close to flat as possible - throughout the entire movement. The moment your lower back rounds, you have gone beyond your hamstring's range of motion, and the load shifts to your lumbar spine.

This is where most stiff-leg deadlift injuries occur. People go too deep with too much weight, their back rounds, and the load on the spinal discs becomes excessive. Respect your current flexibility. Depth comes with time.

How Much Weight Should You Use?

The stiff-leg deadlift should always be lighter than your conventional deadlift and typically lighter than your RDL. The nearly straight leg position creates a longer lever arm and places more stress on the hamstrings per kilogram of weight.

Starting points:

• If you conventional deadlift 120kg, start stiff-leg deadlifts at 50-60kg
• If you conventional deadlift 80kg, start at 35-45kg
• If you conventional deadlift 60kg, start at 25-35kg

Progress slowly - 2.5kg per week is aggressive enough. The hamstrings are strong but the tendons attach at vulnerable points (the sit bones and behind the knee), and these connective tissues need time to adapt.

Programming for Hamstring Growth

Primary Hamstring Exercise

• 3-4 sets of 8-12 reps
• Controlled tempo: 3 seconds down, 1 second pause at the stretch, 2 seconds up
• Rest 2 minutes between sets
• Once per week, possibly twice if recovery allows

As a Secondary Movement After Squats

• 3 sets of 10-12 reps
• Moderate weight
• After your main squat work to pre-exhaust hamstrings before leg curls

High-Rep Hamstring Finisher

• 2 sets of 15-20 reps with light weight
• Emphasis on the stretch and squeeze, minimal rest between sets
• At the end of a leg session

Stiff-Leg Deadlift on a Deficit

Standing on a 5-10cm platform (a weight plate works) increases the range of motion further. This is an advanced variation only for lifters who can already touch the floor with straight legs without lower back rounding.

The deficit version creates an even more extreme hamstring stretch under load. Use 10-15 percent less weight than your regular stiff-leg deadlift.

Programming: 3 sets of 8-10 reps. Do not attempt this variation until you have been doing regular stiff-leg deadlifts for at least 3 months and your hamstring flexibility allows it safely.

Dumbbell Stiff-Leg Deadlift

Using dumbbells instead of a barbell allows a more natural arm path and can be more comfortable for people with wrist issues. Hold dumbbells in front of your thighs and perform the movement identically.

An advantage of dumbbells is that they can travel beside your legs rather than in front of them, keeping the load slightly closer to your centre of gravity.

Good starting weights: 10-16kg per hand for men, 6-10kg per hand for women.

Single-Leg Stiff-Leg Deadlift

The unilateral version adds a significant balance challenge and isolates each hamstring independently. Stand on one leg, keep that leg nearly straight, and hinge forward while extending the other leg behind you.

This is harder than it looks. Most people wobble dramatically for the first few weeks. Start with bodyweight or a very light dumbbell (4-6kg) and focus on controlling the movement.

Programming: 3 sets of 8 per leg. Hold a dumbbell in the opposite hand for counterbalance.

Common Stiff-Leg Deadlift Mistakes

Too Much Knee Bend

If your knees bend more than 15 degrees, you are doing an RDL, not a stiff-leg deadlift. Lock your knee angle at a slight bend and maintain it throughout. The moment your knees bend more, your quads and glutes take over from the hamstrings.

Going Too Deep With a Rounded Back

Depth without spinal integrity is injury waiting to happen. Your range of motion should be dictated by your hamstring flexibility, not by how low you think the bar should go. Over months of consistent stiff-leg deadlift training, your hamstring flexibility will improve and your range of motion will increase naturally.

Using Too Much Weight

This is not a maximal strength exercise. It is a muscle-building exercise. The stretch at the bottom is the stimulus, not the weight on the bar. If you have to round your back, shorten the range of motion, or use momentum to move the weight, it is too heavy.

Lifting With the Lower Back

If you feel the stiff-leg deadlift primarily in your lower back, one of two things is happening: your hamstrings are not engaging properly (fix with lighter weight and a focus on feeling the stretch), or your back is rounding (fix by reducing range of motion).

Combining Stiff-Leg Deadlifts With Other Hamstring Work

The stiff-leg deadlift trains the hamstrings at long muscle lengths through hip extension. For complete hamstring development, pair it with an exercise that trains knee flexion:

Complete hamstring session:

1. Stiff-leg deadlift: 3 x 10 (hip extension, long muscle length)
2. Lying leg curl: 3 x 12 (knee flexion, short muscle length)
3. Nordic hamstring curl: 3 x 5 (eccentric strength, injury prevention)

This combination hits the hamstrings through both of their primary functions and across multiple muscle lengths. Run this once or twice per week and your hamstrings will grow.

The stiff-leg deadlift is a simple exercise. Stand up. Keep your legs straight. Lower the bar. Feel the stretch. Come back up. But the simplicity is deceptive - the intensity of the hamstring stretch under load is unlike anything else. Start light, progress slowly, and let the stretch do the work. Your hamstrings will respond.