4 Best Spider Curls Form Tips To Build Bigger Biceps

If you’re looking to increase muscle growth to your upper arms, specifically your biceps brachii, then performing different curl variations is a surefire way of making progress.  

But to see consistent gains in your strength and muscle size, you need to keep things varied and that means adding in a few other isolation exercises besides the traditional bicep curls or hammer curls.  

Recommended Reading – Hammer Curls Muscles Worked Plus 3 Benefits For Full Biceps

This is where the dumbbell spider curl comes in.  

Keep reading to learn more about this curl variation, what muscles they recruit, and the best spider curls form for your biceps training.  

What Are Spider Curls

Spider curls are a unique and effective bicep curl exercise that isolates and targets the bicep muscles like few other movements can.  

It’s performed on an incline bench or preacher curl bench using either a pair of dumbbells, an ez bar, or a regular straight bar.  

The key distinguishing feature of spider curls is the angle at which the biceps are worked, thanks to the body’s prone position with the chest fully supported, this prevents the use of momentum and ensures the biceps are engaged through a greater range of motion.

spider curl

Unlike traditional curls, where gravity’s pull can sometimes allow for a rest at the bottom or top of the move, spider curls help to maintain constant tension on the biceps.

This continuous tension is what makes it one of the best exercises for muscle growth and strength gains.

The position of the spider curl also encourages a full range of motion from the stretched position at the bottom to a fully contracted position at the top, optimizing muscle fiber recruitment in the biceps.

Spider curls are performed with a different strength curve compared to other curl variations.  

What this essentially means is where in the range of motion the exercise is most difficult.  

If we consider the bench press as an example, when pressing the barbell up it tends to be most difficult around midway up.  

The same is true of a normal curl exercise, both the top and bottom of the movements are relatively easy with the middle of the range of motion being the sticking point. 

When you compare this to a spider curl exercise, it’s the top of the movement that’s most challenging.  

In some cases, this is why people doing spider curls might perform them to higher reps until they reach failure and then do a series of partial reps to properly exhaust the biceps.  

What Muscles Do Spider Curls Work

The primary muscles worked during spider curls are the biceps and brachialis with support provided by your forearm flexors and triceps.  

Let’s look into the anatomy a bit more to understand how the muscles are recruited and what makes it such a great exercise for arm development.

The star of the show when doing spider curls is, without a doubt, the biceps brachii.  

Your biceps are a muscle group that comprise of two heads (the long head of the bicep and the short head of the bicep muscle) that work together to assist with elbow flexion and forearm rotation.  

When doing spider curls your arms remain just in front of your body, which isolates the biceps and is great for an effective mind-muscle connection.  

The position of your body prevents any of your other muscles from taking over and doing the work leading to maximum muscle contraction of the entire bicep.  


Lying just underneath the biceps brachii, the brachialis plays a supporting role in flexing the elbow.

While the focus is on the biceps, the brachialis also gets a solid workout during spider curls, contributing to the overall thickness of the upper arm.  

Stronger brachialis muscles can enhance the definition between the upper and lower arms, leading to a much better look of your entire arm.  


The brachioradialis is a forearm muscle that helps with flexing your elbow, especially when your biceps are under a lot of tension.  

While it’s not a primary muscle worked during spider curls, it does act as a supporting muscle and therefore benefits from the movement, especially if you perform it with a neutral grip with your palms facing inward.  

Strengthening this muscle not only supports bigger lifts as it makes a big difference to grip strength, but it also contributes to a more developed look of the forearms and lower arm.

Spider curls stand out for their ability to isolate and target your biceps with minimal involvement from other muscle groups.

This isolation allows for a focused intensity that can lead to significant hypertrophy and strength improvements to your arm muscles, making spider curls a great addition to your biceps workout. 

By ensuring proper form and a full range of motion, you can maximize the engagement of these muscles, leading to more effective and visible results.

Spider Curls Form Details

There are a couple of different ways of performing the spider curl exercise, but we think the most effective is to do it using an incline bench or adjustable weight bench with the back pad set to a 45-degree angle.  

This way you can properly support your upper body to eliminate any ‘cheating’ placing the maximum amount of tension where you want it, on the biceps! 

Let’s consider the proper spider curl form so you can build bigger biceps:

Start by setting your choice of bench to an angle that allows you to lean over it comfortably, with your torso against the sloped side.  

This can be anywhere between 30 and 45 degrees.  

Most spider curls are done using an EZ curl bar or a pair of dumbbells.  

Avoid heavier weights to begin with and choose a weight that allows you to perform the exercise with good form but is also going to be challenging on your biceps.

With your chest against the bench back pad, lean forward so that your arms are extended and hanging straight down towards the floor.  

Your feet should be extended behind you and resting on the balls of your feet.  

Take hold of your EZ curl bar or dumbbells with palms facing forward (underhand grip) and ensure your elbows are straight but not locked out. 

From this initial positionExhale as you curl the weight up towards your shoulders.

Focus on moving only your forearms; your upper arms and shoulder joint should remain stationary throughout the exercise.

The key to spider curls is isolation – it’s all about making your biceps do as much of the work as possible. 

Once you reach the top of the curl, take a brief pause and squeeze your biceps as hard as you can.  

This peak contraction is critical for maximizing muscle engagement and growth.

Remember, it’s not about how much weight you lift, but how well you lift it.

Inhale as you slowly lower the bar or dumbbells back to the starting position.  

Control is most important here; resist the temptation to let gravity do the work.  

A slow, controlled descent will increase the time under tension for your biceps, leading to better muscle growth.

Perform your chosen number of reps, keeping the focus on maintaining proper form and a full range of motion.  

Avoid swinging or using momentum to lift the weight – your biceps should feel the burn with each rep.

Expert Tips To Get The Most Out Of Spider Curls

When performing each rep, keep your elbows as low as possible.  

Avoid shrugging up and keep both your shoulders and elbows down.  

This will ensure that the most amount of tension stays on your biceps.  

Try performing the spider curl with a narrow grip if you want to work more of your outer bicep (the long bicep head) or try a wider grip if using a barbell to target more of the inner biceps (the short bicep head).  

Experiment with both grip widths as they can work your bicep heads in different ways.  

If, when performing any curl exercise, you find it a little uncomfortable on your wrists make use of an ez curl bar.  

This allows you to perform the spider curl with a more natural wrist position keeping stress off the joints.  

For even more versatility and to focus more on the brachialis and forearm muscles, try an overhand grip.  

This is a great way of developing that all-important biceps peak.  

Can You Go Heavy On Spider Curls

As long as you stick to the correct form there’s no reason why you can’t go heavy when performing spider curls.  

However, because of the difference in the strength curve when doing spider curls compared to regular biceps curls, this means you probably won’t be able to curl as much weight.  

Another reason why you’ll find spider curls more difficult compared to other curl variations is because you’re not engaging as many muscles.  

Remember, as your chest is fully supported this is going to limit the recruitment of your back and shoulders placing increased tension on your biceps.  

Typically, whichever type of curl you choose, it’s common to stick to higher reps with a light weight.  

Are Spider Curls Better Than Preacher Curls

If you want as much bicep activation as possible then the spider curl would be a better option compared to the preacher curl.  

This is because the spider curl exercise allows for a much greater range of motion when compared to the preacher curl ensuring maximum muscle engagement throughout.  

spider bicep curl

When performing a preacher curl you have to rest the back of your upper arms against the pad of a preacher bench.  

While this reduces the engagement of your shoulder and back muscles it does limit how much of a stretch and contraction you can achieve with your biceps so you can only really perform them to a partial range of motion.  

What Are The Benefits Of Spider Curls

Let’s now take a look at some of the benefits of the spider curl exercise when compared to other curl variations.  

Spider curls provide exceptional isolation of the biceps muscles.

When compared to standing or seated curls, the prone position when doing a spider curl minimizes the involvement of the shoulders and back, directing the focus squarely on your biceps.

The positioning during spider curls makes it difficult to use any momentum to lift the weight.

This means that every rep is performed with strict form, maximizing muscle engagement and growth which ultimately leads to better gains.

The angle at which spider curls are performed places the biceps under constant tension throughout the exercise, from full extension to peak contraction.  

This increased time under tension is super important for muscle hypertrophy.

Spider curls allow for a greater range of motion when compared to other variations.

Starting from full arm extension ensures that the muscle is properly stretched and contracted through its entire length, which can lead to better muscle growth.  

The strict form and isolated nature of the spider curl can help to improve any mind-muscle connection.

Being able to focus solely on the bicep contraction without distractions means better quality reps and more effective bicep workout. 


When it comes to bicep exercises, the spider curl is certainly one of the best.  

Its ability to isolate your biceps, helping to promote strict form while maximizing muscle engagement makes it a must-have in any arm workout. 

By incorporating spider curls into your next arm workout, you’re ensuring focused and effective bicep training that can lead to noticeable gains.

Don’t overlook this simple yet highly effective exercise and give spider curls a try. 

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