How to Do Skull Crushers, the Ultimate Triceps Power Move

The skull crusher is a key triceps exercise that works wonders for your entire arm and more. Here’s how to do it with proper form.

Jan 26, 2025 - 17:29

How to Do Skull Crushers, the Ultimate Triceps Power Move

Building an action figure-level upper body is a little more complex than picking up a set of dumbbells a few times a week. Constructing a strong chest, capped shoulders, and sizeable arms starts with a well-thought-out training split tailored to your individual physique. While the bench press builds your chest, dumbbell overhead press your shoulders, and dumbbell rows your back, nothing helps sculpt massive triceps quite like the skull crusher.

Although your triceps are key in building a well-rounded upper body, they play a far more important role than just helping you fill out a T-shirt. The three-headed triceps brachii muscle (the chief beneficiary of skull crushers), impacts everything from sports to everyday movements, working with the lats to bring the arm toward the body and playing a huge role in the extension of the elbow joint.

How to Do Skull Crushers

Lie on a bench with a straight barbell or EZ bar on your lap. Place hands shoulder-width apart on the bar with palms facing down and wrists straight.
Raise the bar above your collarbone.
While keeping your shoulders stable, slowly bend at the elbows, bringing the weight down just past your head. Keep the elbows pointing straight ahead as you lower the weight.
Straighten your elbows, pushing the weight back to the overhead starting position. Be sure to keep your arms perpendicular to your body and only extend your elbows.

Skull Crusher Benefits

While skull crushers are a triceps exercise mainstay, they're often underrated for their value in building coordination between the upper back and triceps. The triceps are more than showy beach muscles. Try getting through your day without the tris. You’ll be unable to sign your name, lift a glass, or wash your hair. As for sports, Giannis Antetokounmpo couldn't launch a jumper or dunk a basketball without his massive tris anchoring the ball. Nor could Caeleb Dressel glide through the water with a powerful butterfly or freestyle stroke without long, lean tris supporting his 6-foot-4-inch wingspan.

What Muscles Do Skull Crushers Work?

One of the best exercises for building strength and mass in your triceps is skull crushers, which also work the stabilizer muscles of your shoulders. During the movement, the tris work with the pectorals and anterior deltoids to push the weight up and control it during the lowering phase.

Pro tip

Keep your elbows in. Allowing them to flare out takes the load off the triceps. Likewise, if you let your arms move back and forth, you put a load on your shoulders, which takes away the muscle- and strength-building benefit to the triceps and can lead to injury.

How to Add a Skull Crusher Into a Workout

The skull crusher is a versatile move when it comes to organizing your workout, and a foundational one for a triceps-focused routine. As an upper-body push, it fits nicely between upper-body pull exercises or lower-body movements. Since it’s possible to go heavier with skull crushers—as opposed to bodyweight triceps moves like bench dips or diamond pushups—it makes sense to have skull crushers later in a triceps workout.

Best Skull Crusher Variations

Skull crushers offer so many variations that some view the exercise as a series of moves rather than just one. As with any movement, start with a light weight to master the move, then increase weight accordingly.

Variation 1: How to Make Skull Crushers Easier

Going with a lighter weight (or simply the bar) is recommended for beginners or even newcomers to skull crushers to master form before adding weight. A lying cable skull crusher may or may not be easier, but dealing with cable resistance instead of iron at least eliminates the slight possibility of hitting your face or head. The cable forces you to keep tension in the cables and thus engage your triceps throughout the move.

Variation 2: How to Make Skull Crushers Harder

The most popular variation—with dumbbells—might seem more manageable than its barbell counterpart. But it’s actually more of a challenge to keep the elbows in and avoid taking the load off the triceps and putting it on the shoulders. Skull crushers performed on a bench at a slight incline add to the degree of difficulty. With the incline, you’re increasing the stretch on the triceps and targeting the muscle from different angles. For an added challenge, swap out the dumbbells for an EZ-bar to pump out a few reps of the loved (and loathed) EZ-bar skull crusher.

Common Skull Crusher Mistakes to Avoid

When it comes to isolating and building the triceps, few exercises work the muscle as well as a skull crusher. While the movement is a key component in building mammoth arms, it's essential to make sure you are selecting the proper weight, keeping a tight grip on the bar or dumbbell, and controlling the movement from start to finish to prevent injury.

Flaring Your Elbows

Flaring your elbows can strain your elbow and shoulder joints, so be sure to keep them tucked in towards your sides. This also helps you feel the movement more in your intended muscle, the triceps.

Incorrect Grip

When you use dumbbells to perform a skull crusher, use a neutral grip with your palms facing each other. This helps you keep your elbows tucked and is less stressful on your wrists.

Swinging the Weights

This is a big one and all too common. Don't swing the weights or use any momentum from your shoulders and back. Just let the exercise be felt in your triceps by using control. That's where the gains are.

Going Too Heavy

No bonus points for going too heavy. Choose a weight that lets you target your triceps with control, going slowly and not using any momentum. You should be able to do at least 10 reps, as this is a small muscle group, so choose your weight accordingly.

Inconsistent Range of Motion

There are a few ways to do a skull crusher, whether you choose behind your head, to your eyes, to your chin, or wherever you feel the best stimulus. But wherever you choose, be sure to keep your reps consistent within your routine from week to week so you can track your progress accurately. The next time you program a new routine, you can choose a different range of motion to try throughout that routine if you want variety.