What does the spider curl work?

The biceps does the work and the forearm assists. Because the chest is on the pad and the arms hang free, the shoulder contributes nothing. The arms-in-front position puts slack in the long head of the biceps, so the short head carries more of the load.

What angle should the bench be for spider curls?

Low enough that your arms hang clear in front of your chest with a gap between your upper arms and your torso. Around 45 degrees works for most people, and shorter arms may want it shallower. Set it near vertical and you have effectively gone back to a standing curl.

Spider curls or incline curls, which is better?

They do opposite things and neither wins. Spider curls hang the arms in front of you, which puts slack in the long head. Incline curls hang the arms behind you, which stretches it. Doing one of each covers both ends of the shoulder position.

Do spider curls keep constant tension on the biceps?

No dumbbell exercise does. The load your biceps feels depends on where the dumbbell sits relative to your elbow, and that changes throughout every rep. What spider curls do provide is a position with no way to swing, lean or use the shoulder.

Why do spider curls feel so much harder than normal curls?

Because you have removed all the help. Standing, the body leans a little and the shoulder swings a little, and both contribute more than most people notice. Expect a considerably smaller dumbbell here.

Can you do spider curls without an incline bench?

Not properly. The bench is what holds your chest up and lets your arms hang clear in front of you. Leaning over something at the wrong height usually turns into a bent-over row for the arms. If you have no incline bench, a seated concentration curl gives you a similar no-cheating position.

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Dumbbell · intermediate · upper arms

Dumbbell spider curl

Also called Prone incline curl, Spider curls, Prone dumbbell curl, Dumbbell spider curl.

The short answer

The spider curl is done lying face down on an inclined bench with your arms hanging straight below you. Your biceps does the work and your forearm assists. Because your chest is pinned to the pad and your arms hang in front of your body with nothing under them, there is no way to swing, lean or borrow from the shoulder. The arms-in-front position also puts slack in the long head of the biceps, which puts this in the same family as a preacher curl.

How to do it

Step oneSet an incline bench to approximately 45 degrees and lie face down with your chest against the pad.
Step twoHold a dumbbell in each hand with your arms hanging straight down and palms facing forward.
Step threeCurl the dumbbells upward by contracting your biceps, keeping your upper arms perpendicular to the floor.
Step fourPause at the top of the movement and squeeze your biceps.
Step fiveSlowly lower the dumbbells back to the starting position.

What usually goes wrong

Each starts with what you would notice.

The movement feels almost identical to a standing curl.

WhyThe bench is set too upright. The closer to vertical it is, the closer your arms hang to where they would beside your body, and the position that makes this a different exercise disappears.

FixLower the bench until your arms hang clear in front of your chest with daylight between your upper arms and your torso. Around 45 degrees suits most people and shorter arms may want it shallower.

Your elbows drift backward and it starts to feel like a row.

WhyThe upper arm is swinging back at the shoulder, which lets your back help lift the dumbbell.

FixHold the upper arms pointing straight down at the floor for the whole rep. Only the forearm should swing, and it should swing forward and up, not back toward your hip.

Your chest lifts off the pad on the harder reps.

WhyYou are pushing off the bench to help, which is the one route out this position still leaves open.

FixKeep your chest, and ideally your chin, in contact with the pad from the first rep to the last. If it lifts, the set is finished, whatever the rep count said.

The dumbbells feel much heavier here than they do standing.

WhyNothing is going wrong. You have removed the swing, the lean and the shoulder contribution, all of which were doing more than you thought.

FixUse smaller dumbbells and let the number be what it is. This is a position for finding out what the biceps can lift, not for setting a record.

Spider curl or incline curl

These two are the cleanest opposites in arm training, which makes them easy to understand together.

On a spider curl your arms hang in front of your torso. On an incline curl, sitting back against a raised bench, your arms hang behind it. The long head of the biceps runs up past the shoulder, so where your upper arm sits changes how long that head is before the rep even starts. Arms forward puts slack in it. Arms back pulls it taut.

That makes the spider curl the version where the long head contributes least and the short head carries more, in the same way a preacher curl does. The incline curl is the version that loads the long head at its longest.

Neither is the better curl. If you do one of each, you have covered both ends of the shoulder position, which is a more useful way to think about it than picking a winner.

Spider curl or preacher curl

Both put the upper arm in front of your body and stop it swinging, so they belong to the same family and work the biceps in much the same position.

The difference is what holds the arm. A preacher bench supports the back of your upper arm on a sloped pad, so the arm rests on something. A spider curl leaves the arm hanging free with nothing underneath it, held in place only by your chest being on the bench.

The free-hanging version is less forgiving. There is no pad to press into on the last reps, so a rep either happens or it does not. Choose the preacher if a bench is what you have, and this if you would rather nothing helped.

Constant tension is not available with a dumbbell

The claim attached to this movement almost everywhere is that it keeps constant tension on the biceps through the whole range. That is not possible with a dumbbell and it is worth knowing why.

A dumbbell pulls straight down and does nothing else. How hard your biceps has to work at any instant depends on where the dumbbell sits relative to your elbow, and that distance changes continuously as the forearm swings. So the load rises and falls through every single rep, on this curl and every other one. Constant tension is something a cable or a band can approach. A free weight never does.

What the position genuinely delivers is the removal of every cheat. Your chest is on a pad, your arms hang with nothing under them, and there is no swing available. That is a real and specific thing and it does not need dressing up.

A particular shape of arm is not on offer. The short-head emphasis is a fair reading of the position; the promise about what that looks like is not something anyone can make.

What it is for

The dumbbell spider curl is an upper arm exercise targeting the biceps. Performed face-down on an incline bench, this variation eliminates body movement and keeps constant tension on the biceps throughout the entire range of motion.

Questions people ask

What does the spider curl work?: The biceps does the work and the forearm assists. Because the chest is on the pad and the arms hang free, the shoulder contributes nothing. The arms-in-front position puts slack in the long head of the biceps, so the short head carries more of the load.
What angle should the bench be for spider curls?: Low enough that your arms hang clear in front of your chest with a gap between your upper arms and your torso. Around 45 degrees works for most people, and shorter arms may want it shallower. Set it near vertical and you have effectively gone back to a standing curl.
Spider curls or incline curls, which is better?: They do opposite things and neither wins. Spider curls hang the arms in front of you, which puts slack in the long head. Incline curls hang the arms behind you, which stretches it. Doing one of each covers both ends of the shoulder position.
Do spider curls keep constant tension on the biceps?: No dumbbell exercise does. The load your biceps feels depends on where the dumbbell sits relative to your elbow, and that changes throughout every rep. What spider curls do provide is a position with no way to swing, lean or use the shoulder.
Why do spider curls feel so much harder than normal curls?: Because you have removed all the help. Standing, the body leans a little and the shoulder swings a little, and both contribute more than most people notice. Expect a considerably smaller dumbbell here.
Can you do spider curls without an incline bench?: Not properly. The bench is what holds your chest up and lets your arms hang clear in front of you. Leaning over something at the wrong height usually turns into a bent-over row for the arms. If you have no incline bench, a seated concentration curl gives you a similar no-cheating position.