How is the single-leg hyperextension different from a regular hyperextension?

The torso is just as heavy, but only one leg extends the hip to lift it, so each side works much harder and the pelvis has to resist twisting. It is a way to make the bodyweight Hyperextension harder and to train each side on its own.

What should the free leg do?

Hold it straight behind you, roughly in line with your body, and keep it there for the whole set. Squeezing the glute on that side keeps the leg level and the hips square, and the free foot should never touch the footplate to help.

Should my back round at the bottom?

Some upper-back rounding as the torso lowers is normal and shifts more of the work into the hamstrings and glutes. Avoid forcing extra rounding or bouncing out of it, and if you have a history of disc problems keep the spine closer to neutral.

Can I add weight to the single-leg hyperextension?

Yes, once you can complete controlled bodyweight reps on both legs, hold a light weight plate or dumbbell against your chest. Slowing the lowering phase or pausing at the top are other ways to make it harder without extra load.

What if one side is much weaker?

Start each set with the weaker leg and stop the stronger side at the same number of reps. Matching reps this way lets the weaker side catch up without widening the gap.

Single-Leg Hyperextension

What Is the Single-Leg Hyperextension?

Single-Leg Hyperextension is an isolation exercise that primarily targets the hamstrings and also engages the glutes and lower back. It is an intermediate-level movement performed on a 45-degree hyperextension bench with one ankle hooked under the roller and the other leg held straight behind the body, so a single hip does the work of raising the torso.

The exercise trains the posterior chain one side at a time without adding external weight. Because the torso weighs the same while only one leg drives the lift, each side works considerably harder than in the two-legged version, and any difference in strength between the left and right sides shows up quickly. It is usually programmed as an accessory after the main lower-body lifts, or as a unilateral option for lifters who find the bodyweight Hyperextension too easy.

On the two-legged version, a study of resistance-trained women found the 45-degree Roman chair back extension activated the biceps femoris more than both the Romanian deadlift and a seated machine back extension, with no difference in erector spinae activity between the three. The single-leg version keeps the load on the spine the same and shifts a larger share of the hip extension onto the anchored leg's hamstrings and glute, while the glute of the free leg works to hold that leg up. Letting the upper back round as the torso lowers and finishing each rep with a hard glute squeeze moves more of the work into the glutes, while holding the spine rigid throughout leaves more of it to the lower back.

The movement suits lifters who already perform the two-legged hyperextension with full, controlled reps and want more hamstring and glute work per side. If the single-leg version is too hard, build up with the Hyperextension and the Single-Leg Glute Bridge first, and focus on feeling the working hamstring and glute lift the torso rather than the lower back.

Muscles Worked

MuscleActivation

Biceps Femoris: Primary
Semitendinosus: Primary
Erector Spinae: High
Gluteus Maximus: High
Semimembranosus: High
Adductor Magnus: Medium
Thoracolumbar Fascia: Medium
External Oblique: Low
Gluteus Medius: Low
Lower Trapezius: Minimal

Instructions

Set the pad of a 45-degree hyperextension bench so its top edge sits just below your hip crease.
Step in, rest your thighs on the pad and hook one ankle under the roller with that foot flat on the footplate.
Lift the other foot off the footplate and hold that leg straight behind you, roughly in line with your body.
Hold your hands together in front of your chest with your elbows pointing down.
Start with your body in a straight line from head to anchored heel, glutes tight and hips square to the pad.
Bend at the hips to lower your torso toward the floor under control, letting your upper back round gently as you reach the bottom.
Squeeze the hamstrings and glute of the anchored leg to raise your torso, keeping your head in line with your spine.
Stop when your body is back in a straight line, without arching past it, and keep the free leg level throughout.
Complete your reps, then switch legs and repeat.

Common Mistakes

Overextending at the top
Arching past a straight line from head to heel compresses the lower back and takes work away from the hamstrings and glutes.
Letting the hips twist
When the free leg drops or swings, the pelvis rotates toward that side and the lower back absorbs the uneven load.
Resting the free leg on the footplate
Touching down with the free foot to help the lift turns the set back into a partly two-legged hyperextension.
Dropping into the bottom
Falling into the stretch and bouncing out of it strains the anchored hamstring and removes the controlled lowering that builds strength.
Setting the pad too high
A pad above the hip crease blocks the hips from bending, so each rep becomes rounding and arching through the lower back.
Cranking the neck up
Lifting the chin to look forward at the top strains the neck, so keep the head in line with the torso.

Injuries

Single-Leg Hyperextension is a medium risk exercise when performed with proper technique. The lower back is the most common strain point, usually from arching past a straight line at the top or from letting the hips twist as one leg drives the lift. The hamstrings of the anchored leg are also exposed in the stretched bottom position, especially when the torso drops quickly or bounces out of the bottom.

Set the pad just below the hip crease so the hips can bend freely, lower the torso under control, and stop each rep once the body forms a straight line. Keep the hips square to the pad and the free leg level so the pelvis does not rotate. A pad that presses into the front of the hips or a roller sitting on the Achilles tendon can cause discomfort, so adjust both before the first rep.

If the single-leg version is too demanding, return to the two-legged Hyperextension, shorten the range, or build unilateral hip extension strength with the Single-Leg Glute Bridge. To progress, slow the lowering phase, pause at the top, or hold a light weight plate against the chest once bodyweight reps are smooth on both sides.

Stop the set if you feel sharp or radiating pain in the lower back or leg, or a sudden pulling sensation in the hamstring. Anyone with a history of disc problems, spinal stenosis or persistent lower back pain should check with a healthcare provider before adding this exercise.

Overview

Primary Focus: Hamstrings
Equipment: Machine and body weight
Modality: Strength
Difficulty: Intermediate

Alternative Exercises

Other Names for the Single-Leg Hyperextension

The Single-Leg Hyperextension is also known as:

Single-Leg Back Extension

Frequently Asked Questions

Q: How is the single-leg hyperextension different from a regular hyperextension?: The torso is just as heavy, but only one leg extends the hip to lift it, so each side works much harder and the pelvis has to resist twisting. It is a way to make the bodyweight Hyperextension harder and to train each side on its own.
Q: What should the free leg do?: Hold it straight behind you, roughly in line with your body, and keep it there for the whole set. Squeezing the glute on that side keeps the leg level and the hips square, and the free foot should never touch the footplate to help.
Q: Should my back round at the bottom?: Some upper-back rounding as the torso lowers is normal and shifts more of the work into the hamstrings and glutes. Avoid forcing extra rounding or bouncing out of it, and if you have a history of disc problems keep the spine closer to neutral.
Q: Can I add weight to the single-leg hyperextension?: Yes, once you can complete controlled bodyweight reps on both legs, hold a light weight plate or dumbbell against your chest. Slowing the lowering phase or pausing at the top are other ways to make it harder without extra load.
Q: What if one side is much weaker?: Start each set with the weaker leg and stop the stronger side at the same number of reps. Matching reps this way lets the weaker side catch up without widening the gap.