Back extension

What it is

Set yourself on a forty-five degree or horizontal back extension bench, ankles secured, with the top pad just below your hip bones so your hips can move freely.

Let your torso lower by hinging at the hips, keeping your spine in its normal shape, until you feel a stretch at the back of your thighs. Rise until your body is straight — not past it.

Hold a weight at your chest to load it.

What it demands

Mostly hip extension, from gluteus maximus and the hamstrings, with the erector spinae group working isometrically to hold the spine steady.

Hamstring length, which again sets the depth.

The name says the spine extends, and in the version worth doing it mostly does not. The pad position is what decides this: below the hip bones and you can hinge, above them and your hips are pinned so the movement has to come from your back.

What usually goes wrong

The pad too high. Pins the hips and forces the lumbar spine to do the whole movement. This is the setup error that produces the exercise's reputation.

Rising past straight. Continuing into extension at the top, sometimes called a hyperextension, which is where the name comes from. There is no benefit to it and the load at the end is entirely on the lower back.

Swinging. Bouncing at the bottom to get back up.

Hands behind the head with a heavy load, which adds leverage most people are not ready for.

Where it sits

Genuinely useful and widely misunderstood, largely because of its name and its setup.

Done as a hinge it is a good way to load hip extension and spinal position together without a barbell — a reasonable step between the glute bridge and the Romanian deadlift, and one of the few gym machines that trains a pattern rather than isolating a muscle.

Done as its name suggests, with the hips pinned and the spine doing the work, it is a much narrower exercise and not what this record describes.