Spider Curl: How to Do It, Muscles Worked and Why It Beats Cheating

Lie face down on an incline bench, let your arms hang straight towards the floor, and curl. That is a spider curl, and its whole appeal is what it prevents: no hip drive, no shoulder swing, no leaning back at rep eight to sneak the weight up. Your chest is on the pad, so your biceps either lift the dumbbell or they don't.

It's an accessory move rather than a foundation, and it works best alongside a curl that loads the stretched position. Here's how to set it up, what it trains, and the mistakes that turn it back into an ordinary sloppy curl.

How to do a spider curl

You need an adjustable bench and a pair of dumbbells or an EZ bar. Set the bench to roughly 45 degrees, or steeper if it goes there.

1. Get on the bench chest-first. Lie face down with your chest against the pad and the top edge somewhere around your collarbone. Plant your feet wide on the floor for balance, or kneel on the seat if the bench is tall.
2. Let your arms hang. Holding the weight, drop your arms straight down so they are vertical, or as close as the bench allows. Elbows soft, not locked. This hanging position is the whole point; if your arms swing back under the bench, slide up a little.
3. Curl, without moving your elbows. Bend at the elbow and bring the weight up towards your shoulders. Your upper arms should stay pointing at the floor throughout, moving as little as you can manage.
4. Squeeze at the top. Pause for a beat where the biceps is fully shortened, keeping your wrists neutral rather than curling them in.
5. Lower slowly. Take two or three seconds on the way down and go all the way to straight arms. Every centimetre you cut off the bottom is range you are not training.

Muscles worked

• Biceps brachii. The main mover, and the reason you're here. Both heads flex the elbow, and with your shoulder held in a fixed, flexed position, the long head works in a shortened state throughout the rep.
• Brachialis. Sitting underneath the biceps, this one does a large share of elbow flexion regardless of grip, and building it pushes the biceps up and makes the arm look thicker from the side.
• Brachioradialis. The forearm muscle that runs from your elbow towards your thumb, most involved when your palms face inwards or down.
• Wrist and finger flexors. They hold the bar or dumbbell, and on a long set they let you know about it.

Nothing else contributes, which is unusual for a curl. That isolation is the point of the movement and also its limit: it builds arms, and it will not do much else for you.

If you're loading these up at home, a pair of adjustable dumbbells and a decent weight bench cover this exercise and about forty others.

Benefits

Cheating becomes impossible. With your torso pinned, the momentum tricks that inflate a standing curl are simply unavailable. What you lift is what your biceps lifted.

Constant tension through the top half. Gravity pulls straight down and your arms hang straight down, so the resistance stays meaningful right through the contracted position where a standing curl goes slack.

It's kind to the lower back. Nothing is loading your spine, which makes it a useful arm exercise on a day when you've already deadlifted or rowed heavily.

Easy to progress honestly. Because form has so little room to degrade, an extra 2kg on a spider curl means something. Standing curls flatter you; these don't.

It fits the evidence on where to load a curl. Work comparing arm-curl training in the first half of the range against the second found greater muscle growth from training in the initial, more stretched portion (initial versus final range of motion in the arm curl, 2023). The spider curl covers the opposite end, which is exactly why it belongs next to an incline or preacher curl rather than instead of one.

Common mistakes

Elbows travelling backwards. The most common fault by a distance. It shortens the range, hands work to the shoulders and drains the tension out of the top. Fix it by watching your upper arms in a mirror for a set, or by lowering the weight until they stay put on their own.

Cutting the bottom of the rep. Stopping at 30 degrees of elbow bend feels stronger and trains less. Straighten your arms fully at the bottom of every rep, even when it means dropping the weight.

Wrists curling under. Flexing your wrists at the top shifts load onto the forearms and puts strain through the joint. Keep your knuckles roughly in line with your forearm.

Bench too flat. A 30 degree bench leaves your arms angled back rather than hanging, which slackens the bottom of the movement. If your bench does not go steeper than that, use the upright side of a preacher bench instead.

Rushing. Two seconds down, a pause at the top. Fast reps on an isolation move are pure ego, and the eccentric is where a lot of the growth stimulus lives.

Neck craning up. Keep your head in a neutral position looking at the floor. Lifting your chin to watch yourself for a whole set leaves you with a sore neck and nothing to show for it.

Variations

• EZ bar spider curl. The angled grip is easier on the wrists than a straight bar and lets you load both arms with one implement. Grab an EZ bar and this becomes the default version for most people.
• Dumbbell spider curl. Two dumbbells, each arm working independently, which stops your stronger side carrying the weaker one. You can also supinate as you curl, turning your palm up through the rep, to bias the biceps a little harder.
• Hammer spider curl. Palms facing each other throughout. Shifts more of the work to the brachialis and brachioradialis, and the same logic as standard hammer curls applies here.
• Cable spider curl. Set a low pulley in front of the bench so the cable pulls forward rather than straight down. Tension stays even across the whole range instead of peaking in the middle.
• One-arm spider curl. Slower, but it lets you brace properly with the free hand and hunt for the fault in your weaker side.

Sets and reps

Arms respond to volume and to being taken close to failure, and they recover quickly, so this is a movement you can do more of than you might for a squat.

• Building size: 3 to 4 sets of 10 to 15 reps, one or two sessions a week. Rest 60 to 90 seconds.
• Finishing an arm day: 2 sets of 15 to 20 with a light weight, taken to a real burn.
• Learning it: 3 sets of 12 with something embarrassingly light, focused only on keeping the upper arms still.

Slot them after your heavier pulling work, when your back and grip are already warm. A sensible arm day pairs them with incline dumbbell curls for the stretched position and something for the triceps; the workouts section has the rest of the moves. Two strength sessions a week covering all the major muscle groups is the NHS baseline, and arms alone will not get you there (NHS physical activity guidelines for adults).

One caveat on the shoulder-position debate: a 2025 comparison of preacher curls against Bayesian cable curls, matched for resistance profile, found the shoulder angle itself made little difference to growth or strength (shoulder flexed versus extended elbow flexion training, 2025). Variety in your curls is worth having for the change in where the load peaks, not because one bench angle holds a secret.

Recommended reads

1. Preacher curl technique guide
2. Incline dumbbell curl technique guide
3. The best adjustable dumbbells in the UK
4. The best weight bench in the UK
5. The best EZ bar in the UK