Back extension: the 45-degree bench, the glute version and the reverse hyper

A back extension is a hinge done face down on a bench: your hips rest on a pad, your heels are hooked under a roller, and you bend forward at the hips and come back up until your body is straight. The bench goes by several names, a Roman chair or a hyperextension bench among them; most are set at 45 degrees, and some hold you level with the floor. It trains the muscles that extend the hips and the muscles along the spine: the glutes, the hamstrings and the back extensors.

It's the hinge in the back workout when the week already has a heavy Romanian deadlift, and the one that needs no barbell. This page covers the setup, the hip-led and back-led versions, the hand and knee positions, the reverse hyperextension, what weeks of training on it did in the studies, the faults, and the sets.

How to do a back extension

1. Set the pad so its top edge sits just below the bony points at the front of your hips. Too high and the pad blocks the hinge; too low and you'll slide off.
2. Hook your heels under the roller, legs straight, feet about hip-width apart.
3. Cross your arms over your chest to start. Your body is one straight line from your head to your heels.
4. Hinge down from the hips, keeping your back still, until your torso is close to vertical or you feel the backs of your thighs stop you.
5. Rise by squeezing your glutes and driving your hips into the pad, until you're back in one straight line. That line is the top of the rep.

Two seconds up, two seconds down is a good pace to start. Hold a plate against your chest once 15 controlled reps are easy.

Hip-led or back-led: what changes

You can do the rep two ways: hinge at the hips with the spine held still, as in the steps above, or keep the hips still and curl and uncurl the spine. In 16 adults with strength-training experience, eight men and eight women doing body-weight reps with those two instructions, the hip-led version produced larger peak turning forces at the back and at the hips than the spine-led one, while glute activity showed no significant difference between the two.¹ Holding the spine still was the instruction, not the result: the lower spine still bent in both versions. One-legged reps raised glute activity in the working leg compared with two-legged reps, in both versions. The authors judged the hip-led version the more efficient way to train the hips and the back, because its turning forces were higher.

That's why the steps teach the hinge. The spine-led version is a different exercise, with smaller forces at the hip.

Back extensions for glutes

A common cue for putting the back extension on the glutes is turning your feet out, which turns the hips out. One study tested the hip turn: in 12 healthy adults, seven men and five women, glute and hamstring activity showed no difference between hips turned in and hips turned out, or between a normal back position and an exaggerated arch. The back's own muscles worked 18% more with the hips turned in and 25% more with the arch.² So, in that study, turning the hips out didn't change the glutes.

What did change glute activity in the back-extension studies above: going one leg at a time, as above, and, in 18 male amateur athletes, bending the knees to 90 degrees, which raised glute, lat and back-muscle activity compared with straight legs.³ If you want the glutes to do more, try single-leg reps, and squeeze them hard at the top. The glute workout builds the full session.

Hands, pad and bench angle

• Hands behind your head made the lower trapezius, between the shoulder blades, work harder than arms crossed over the chest, in the same 18 athletes.³ It also moves weight further from your hips, so it's a step up from crossed arms.
• Strapping the pelvis down didn't change back or glute activity in 22 adults, 11 men and 11 women; setting the hips at 40 degrees of bend reduced the activity in one of the hamstrings.⁴
• 45 degrees or flat are both standard. A flat bench holds your body level with the floor at the top of the rep, so the same rep is harder there.

What weeks of training on it did

Three trials trained healthy people on a back extension bench and tested them before and after:

• Endurance went up. In 36 healthy volunteers, half of whom trained (one set of 15 to 25 reps three times a week for eight weeks), the trained group could hold a back extension 42% longer than before; the other half did not change.⁵ In 44 untrained young adults, 29 of whom trained twice a week for ten weeks, the number of reps they could do rose 26% with a single set and 61% with multiple sets; the 15 who did not train showed no benefit.⁶
• Maximum strength, tested separately, showed no significant increase. The 36 volunteers showed no significant increase in isometric back-extension strength.⁵ In a trial of 15 healthy volunteers, nine women and six men, the nine who trained once a week for 12 weeks, one hard set of 8 to 20 reps holding plates, averaged about 7% more on a test machine afterwards, a change that wasn't statistically significant, although the weight they used on the bench went up.⁷ The 44 young adults showed no significant difference in strength.⁶

So the trials found the back extension builds the ability to do more back extensions, for longer and with more weight, rather than maximum strength on a separate test. All three are small, and none measured muscle growth. Use it as a hinge for volume and endurance beside a heavier hinge, not as a replacement for one.

The reverse hyperextension

The reverse hyper flips the exercise: your upper body lies on a pad and your legs swing up behind you. In 10 adults with an average age of 23, the reverse hyperextension produced 34 to 71% more peak activity than the back extension in the back muscles, the glutes and the hamstrings.⁸ Load doesn't scale neatly: in 20 recreationally active adults, 13 men and 7 women, there were few differences between 100% and 150% of body weight on the machine, while 50% produced less back and glute activity than either. The authors' summary is that more load doesn't raise force and muscle activity in step.⁹

It has also been part of a program that grew the glutes. In 19 resistance-trained adults over six weeks, glute thickness rose similarly in a program of hip thrusts, reverse hyperextensions and long jumps and in one of back squats, barbell step-ups and box jumps.¹⁰¹¹ Without the machine, lie face down on a high bench with your hips at the edge, hold on, and lift both legs until they're level with your body.

The common faults, and a fix for each

• Arching past straight at the top. Stop when your body forms one line, the top of the rep in the steps.
• Pad too high. If it sits on your stomach, you can't hinge. Lower it to just below the front of your hips.
• Swinging. Bouncing out of the bottom takes the work off. Pause for a moment at the bottom, then rise.
• Rounding to get lower. Go only as low as your hamstrings let you while your back stays still.
• Adding a plate too soon. Get to 15 controlled reps with your arms crossed, then hands behind your head, then a plate.
• Training through something that hurts. Sore muscles the next day are normal; anything sharp or lasting isn't. Stop, and see a doctor or a physical therapist.

Sets, reps and where it goes

• Two or three sets of 10 to 15, stopping with a rep or two left. (How to judge reps left.) The American College of Sports Medicine's 2026 position stand, which covers healthy adults, advises at least two sets per exercise.¹²
• As the hinge on a back day, or after the main lifts on a leg day. If the same week has a heavy Romanian deadlift or good mornings, count it with them as hinge work.
• As a glute exercise, one-legged, two or three sets of 10 to 12 each side after a hip thrust.
• Progress from crossed arms, to hands behind your head, to a plate at your chest, then a heavier plate. (Progressive overload covers the options.)

If you'd rather not plan it alone

The back extension is simple to learn; deciding whether it's your week's hinge or a second one beside a heavier lift, and how much hinge work your week can hold, is the part a page can't do. Coaching is the version where your workouts are built around the days you actually have, and a weekly call looks at the week you just had and rebuilds the next one. Coaching to build muscle explains how that works, and here's how to apply. Otherwise: at your next back or leg session, do two sets of 12 back extensions with your arms crossed, hinging from the hips, and write down the reps.