How to Do Spider Curls for Next-Level Biceps

If you're ready to take your biceps workouts to the next level, try them floating from a bench: By putting you at a gravity-defying angle, spider curls can challenge your arms more than normal curls.

They're a moderate-to-advanced exercise, though, so you'll want to make sure you know the right way to do these curls. Fortunately, this article covers it all!

• ​What is a spider curl?​ Also called a prone incline biceps curl, it's an upper-arm exercise that involves lying facedown on an incline bench so your arms are hanging to the sides of the bench holding dumbbells. In this position, you curl the weights up to your shoulders by bending your elbows.
• ​What muscles does the spider curl work?​ They focus primarily on the biceps brachii, commonly called the "biceps." But they also work the brachialis and the brachioradialis, which help bend your elbow.
• ​Who can do this exercise?​ This is a moderate-to-advanced biceps exercise. Master other biceps curl variations before starting this one. Note that if you have a large stomach or breasts, the stomach-lying position may not be comfortable for you. Stop what you're doing if you feel any discomfort.

If you set the bench too low, your arms will probably hit the floor. But if the angle of the bench is too steep, you won't be getting the intended benefit of spider curls — instead of increasing the range of motion, your arms will basically be in the same position as when you're doing standing curls.

At a 45-degree angle, the bench will form a perfectly diagonal line.

If you try to straddle the bench with your butt on the seat, your face will get mashed into the bench. Not good.

Instead, place your knees up on the bench seat so that your thighs, stomach and chest are all firmly against on the back of the bench. The top of your chest and your head should be above the bench.

Focus on keeping your knees, thighs, hips and chest stationary throughout the exercise.

Ideally, during the exercise, the only things that move are your elbows. To really focus on your biceps, you need to keep your upper arms still. They should be completely vertical, or perpendicular to the floor, throughout the entire exercise.

Consider recording yourself on your phone to check your reps.

Spider curls are hard all the way to the top.

For full benefits, curl the weights as high as your possibly can toward your shoulders while keeping those upper arms still. You might feel like you're moving farther than you usually do during curls. That's a good thing.

A lot of curls get easier at the top of each rep. That's not the case with spiders.

That's because, by positioning your torso at an angle, you feel the full effects of gravity on your dumbbells throughout more of the move, says Brandon Lirio, CPT, certified personal trainer, director of BattleGround Fitness and a professional bodybuilder.

Using momentum from your lower power is a common biceps curl mistake. But with this variation, your torso, hips and legs are fixed against the bench, meaning it's tougher to cheat.

"You're eliminating the ability of your torso to move in either direction, so the arm — specifically the biceps tendon — has to do all the work," Lirio says.

Sure, the bench makes it harder to swing your hips around, but you still need to keep your shoulders in place. "If you're doing your spider correctly, basically the upper portion of the arm should be immobilized," Lirio says.

That means you have to be able to move one segment of your arm while keeping the other completely still. This takes practice, and can be the most difficult when holding the dumbbells in a supinated or underhand position with your palms facing up.

Beginners can benefit by doing move with a neutral, or hammer, grip. It makes it easier to keep the upper arm still throughout the exercise. (See more below.)

Using a neutral, or hammer, grip makes it easier to keep your upper arm still so that you better isolate your biceps. This can also be a more comfortable setup for some people's shoulders.

At the top of this spider curl, pause and squeeze the muscles for a full second — or two, says Lirio. This isometric hold will increase the time your muscle is under tension … and it'll feel that much harder.

As you twist the dumbbell, holding your upper arm still will be more difficult.