How To Do Spider Curls

You’ve stuck with doing Regular Curls, Incline Dumbbell Curls, and even Cable Hammer Curls, but you’re still not seeing the thick, defined arms you want.

Why? Because you’re relying on momentum instead of muscle activation.

Most lifters have zero mind-muscle connection when they train biceps.

They load up a curl bar, swing the weight up, and think they’re building strength. In reality, they’re just cheating their reps, shifting tension away from the biceps brachii and robbing themselves of actual growth.

That’s where Spider Curls come in.

Unlike Preacher Curls or Reverse Curls, which can still allow for elbow drift and shoulder involvement, Spider Curls force your biceps to do all the work.

You’re in an unsupported position, which means you can’t cheat. The entire range of motion keeps your biceps muscle mass under maximum tension, ensuring every rep counts.

If your goal is a physique-oriented look with bigger, stronger, more defined arms, then Spider Curls aren’t optional… they’re essential.

It’s time to ditch the half-rep curls, stop relying on compound movements that don’t fully isolate the individual muscle fibers, and start training like you actually want results.

Let’s break down exactly why Spider Curls work, how they target the short head, long head, and brachialis, and why they need to be in your next pull day workout.

PREACHER CURLS: MUSCLES WORKED

If you’re just curling weights up and down without thinking, you’re wasting reps.

The mind-muscle connection is what separates effective isolation workouts from just going through the motions.

And when it comes to biceps muscle growth, Spider Curls force you to focus on every inch of the movement with dumbbells or a curl bar, ensuring maximum muscle activation in every rep.

Unlike Regular Curls or a Classic Bicep Curl, which allow for momentum and swinging, Spider Curls put you in an unsupported position, meaning your bicep muscles must do all the work.

This is why they are one of the best alternatives to Preacher Curls, which can take tension off the arm muscles when done incorrectly.

Let’s break down exactly which muscles Spider Curls target and how they help you build bigger, stronger arms.

BICEPS BRACHII: SHORT HEAD

The biceps brachii crosses both the shoulder and elbow joint, playing a role in elbow flexion and forearm supination.

It consists of two heads, the short head and the long head, which work together in most upper-body workouts but can be targeted separately with specific movement patterns.

The short head of the biceps attaches to the front of your shoulder and runs down to your forearm.

Its job is to bend your elbow, twist your palm upward, and help keep your shoulder stable when lifting or pulling.

This head is primarily responsible for biceps thickness and peak, giving the rounded, full appearance when flexing.

Most people fail to fully engage the short head because they rely on standard curls, which don’t keep the biceps muscles under tension long enough.

The pattern of Spider Curls eliminates momentum, placing your arm in position to maximize contraction at the top of the curl motion, where the short head is most active.

By performing Spider Curls in an unsupported position on a 45-degree incline curl bench, you remove shoulder involvement and force the biceps muscle fibers to do all the work.

The range of motion may feel shorter than a traditional dumbbell curl, but this is because your elbows are placed slightly in front of your body, putting the short head under constant tension.

BICEPS BRACHII: LONG HEAD

The long head of the biceps starts at the top of your shoulder and runs down the outer part of your upper arm, attaching to your forearm.

Its primary function is to assist in elbow flexion, forearm supination, and shoulder stabilization.

However, the long head plays a more significant role in developing arm width and fullness, which is why neglecting it can leave your arms looking flat from the side.

Most free-weight curls, including the barbell curl and classic bicep curl, allow for elbow movement, which reduces isolation and prevents the long head from staying under tension.

Spider Curls, however, keep the long head engaged for the entire rep, since your elbows remain in a fixed position with no chance to shift the workload elsewhere.

In a Spider Curl, your arms start in a fully extended position, meaning the long head is under full stretch before you even initiate the curl motion.

The unsupported position forces your biceps muscles to work harder, eliminating cheat curls and ensuring maximum tension throughout the range of motion.

For added variety, consider incorporating Cable Curls or Scott Curls to complement your focus on the long head.

BRACHIALIS

The brachialis muscle is often overshadowed by the biceps brachii, but if your goal is to have thicker, more defined arms, you can’t afford to ignore it.

The brachialis sits underneath the biceps, starting from the upper arm bone and attaching to the forearm. Its main job is to bend the elbow, making it a key muscle for arm strength.

Unlike the biceps brachii, the brachialis does not cross the shoulder joint, meaning it doesn’t assist in shoulder movement—it is purely responsible for elbow flexion.

Most classic curls fail to fully engage the brachialis because lifters rely on momentum or shoulder flexion to complete the movement with dumbbells.

Spider Curls, however, place your arms in an inclined position, forcing the brachialis to work harder to initiate the curl motion without cheating the movement.

Since the brachialis sits underneath the biceps, developing it will push the biceps up, making them appear thicker and more prominent.

If you want a truly complete arm physique, you need to train the brachialis directly, and Spider Curls provide one of the best ways to do that.

BENEFITS OF SPIDER CURLS

If you’re serious about biceps growth, you need Spider Curls in your workout routine.

While Preacher Curls are a solid biceps exercise, they come with a drawback: they lock your arms into a fixed position against the preacher curl bench, limiting your range of motion and reducing time under tension.

Spider Curls, on the other hand, eliminate these issues completely.

By resting your chest on an incline bench (preferably set at a 45-degree angle), you allow your arms to hang freely, keeping your elbows slightly out in front.

This optimal starting position ensures maximum muscle activation from the very first curl motion, making it one of the best biceps curl variations for solid arm gains.

Here’s why you should add Spider Curls to your arm workout:

BETTER MECHANICAL TENSION

Spider Curls create maximum mechanical tension by keeping the biceps under load for the entire range of motion.

Unlike Preacher Curls, where the resistance drops at the top, Spider Curls maintain constant strain, forcing more muscle fiber recruitment and leading to greater strength gains over time.

ELIMINATES MOMENTUM

One of the biggest mistakes with spider curls (and most biceps exercises) is using too much momentum.

With Spider Curls, your arms are fully unsupported, meaning there’s no way to cheat the movement.

The result?

Pure biceps activation with zero assistance from the shoulders or lower body.

INCREASES TIME UNDER TENSION

Muscle growth happens when you increase time under tension, and Spider Curls excel at this.

Because your arms start in a slightly flexed position and remain under stress throughout the entire curl motion, your biceps brachii muscle and brachialis muscle work harder for longer, leading to better hypertrophy and muscle size gains.

ENCOURAGES PROPER FORM

Unlike a preacher curl setup, where elbow drift and shoulder flexion can compromise form, Spider Curls naturally encourage proper alignment.

Since your elbows are not pressed into a preacher bench, you remove unnecessary leverage and avoid common mistakes like leaning back or shifting tension away from the biceps.

HOW TO DO SPIDER CURLS

If you want bigger biceps, you can’t afford to waste time with sloppy form or ineffective exercises.

The Spider Curl is one of the best single-joint isolation movements to maximize biceps muscle mass because it eliminates momentum, increases time under tension, and forces maximum contraction.

But only if you do it right.

Follow these step-by-step instructions to master the classic Spider Curl and avoid the most common mistakes that kill your gains.

SPIDER CURLS

SPIDER CURLS: COMMON MISTAKES

If you’re doing Spider Curls but not seeing the biceps muscle mass gains you expect, there’s a good chance you’re making one of these common mistakes.

When done correctly, Spider Curls are one of the best single-joint isolation movements for building bigger arms, but bad form and execution can turn this fantastic movement into a wasted effort.

Let’s break down the biggest mistake with Spider Curls and some mistakes you don’t realize you’re making.

We’ll also cover how to fix them so you can hit your training goals with maximum tension and muscle fiber activation.

USING MOMENTUM (AKA THE CHEAT CURL EFFECT)

If you’re swinging the curl motion, rocking your upper body, or rushing through reps, you’re turning Spider Curls into a cheat curl

And that defeats the entire purpose of this effective isolation workout.

Keep the movement under control by slowing down the eccentric phase (the lowering part of the curl).

Make sure your arm position stays locked in place with elbow flexion being the only moving joint. If you have to swing the weight, drop the ego, and go lighter.

LETTING THE ELBOWS DRIFT BACK

Your elbows should stay slightly in front of your body, but if they start drifting backward, you’re taking tension off the biceps and turning this into an unsupported preacher curl, a much less effective movement.

Keep your arm in position throughout the entire range of motion.

Visualize your elbows being pinned in space. They shouldn’t move forward or backward.

If you struggle with this, use a curl bar, and focus on low-level isometric tension throughout the set.

SHORTENING THE RANGE OF MOTION

If you’re not fully extending at the bottom or failing to squeeze at the top, you’re robbing yourself of full muscle fiber recruitment.

Many lifters cut their reps short, turning Spider Curls into a half-rep regular bicep curl instead of a full contraction movement.

Always use the entire range of motion. Let your biceps muscles fully stretch at the bottom and fully contract at the top.

Control the weight throughout the movement pattern to maintain maximum tension in every rep.

If you struggle with full range of motion, try Cable Curls or Barbell Curls to reinforce proper arm angle and elbow flexion.

RUSHING THROUGH THE REPS

Spider Curls work best when you control the tempo. If you’re flying through curl sets just to hit rep numbers, you’re not maximizing muscle growth.

Speeding through reps reduces time under tension and leads to sloppy form.

Slow it down. Focus on a 2-3 second eccentric phase, meaning you lower the weight under control.

This increases time under tension, which is critical for hypertrophy and strength gains.

SETTING THE BENCH AT THE WRONG ANGLE

Your adjustable weight bench should be at an optimal angle. Too steep and you reduce biceps activation, too flat and you lose stability.

A bad bench angle makes it harder to maintain a neutral head position and a stable foot position.

Set your bench to a 45-degree incline for the best arm angle. This keeps your biceps under mechanical tension while allowing for maximum range of motion.

If you don’t have an adjustable weight bench, try Preacher Curl Machines or Reserve Spider Curls for similar biceps muscle mass activation.

If your arms aren’t growing, it’s not your genetics, it’s your training choices.

Too many lifters rely on momentum instead of muscle activation, swinging through Regular Curls, Incline Dumbbell Curls, and Cable Hammer Curls, hoping for results that never come.

Spider Curls force strict form, eliminate cheating, and keep the biceps under maximum tension, hitting the short head, long head, and brachialis harder than any other biceps curl variation.

If you want bigger, more defined arms, stop wasting reps and start using Spider Curls because nothing else forces your biceps to work this hard.

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SPIDER CURLS FAQ