Skull Crushers: How-To & Common Mistakes

Skull crushers are a tricep-focused upper body push exercise that works all three heads of the tricep, but the long head is the primary muscle worked. Skull crushers can be done using dumbbells, barbells, and resistance bands.

I often program them for my clients, so read on as I share how to do them, who they’re best for, mistakes to avoid, and how to add them to your workout.

How To Do Skull Crushers With Proper Form

There are 3 key steps to do a skull crusher with proper technique.

1. Set up a flat bench with a barbell. Lay on the bench with your feet on the ground. Hold the barbell with your knuckles facing you and hands shoulder-width apart. Extend your arms straight up so the bar is above your chest.
2. Slowly lower the bar down to your forehead, only bending through your elbows. Keep your elbows as tight and close to your body as possible without flaring out to the side. You should only be moving through your elbows, not the shoulders.
3. Once the bar reaches your forehead, press it back to the top starting position. As you press up, follow the same bar path and drive the bar by bending through your elbows. Repeat for the desired reps and sets.

Who Should Do Skull Crushers?

Powerlifters

Strong triceps are crucial for powerlifters. Your triceps must be strong to help drive the weight up in a bench press and stabilize the top lockout. Strengthening the triceps by doing skull crushers is a huge advantage to powerlifters.

CrossFit Athletes

CrossFit athletes do a ton of overhead pressing variations. Strengthening the trices will help spike your numbers in exercises like the split jerk and snatch with an overhead lockout position.

Everyday Gym Go-ers

Stronger triceps can benefit practically everybody who works out. Not only will they make you look bigger or more toned, but they will also serve a function in daily life.

Skull Crusher Common Mistakes

Although it is a simple movement, you must follow the correct form to avoid making these common mistakes.

Using Too Much Weight

Using too heavy weight is the most common mistake I see during a skull crusher. Skull crushers put stress through the wrist and elbow joints, so going too heavy could lead to injury. If the medial head of the triceps is too weak for the weight, that can lead to failure or compensation. Compensating the movement by using your delts to make it more of a press won’t accomplish growing your triceps.

Not Controlling Tempo

Tempo is everything for skull crushers. A slow 3-4 second eccentric tempo will lead to more muscle growth than quickly dropping the bar. Make sure the lowering of the bar to your forehead is slow and controlled. You don’t have to fly through doing this exercise.

Grip Too Wide Or Too Narrow

Your hands should be about shoulder-width apart. A too wide grip will typically lead to the elbows flaring out to the side. When your elbows flare out, the tension is taken off the triceps, and there is more focus on the front delt. A very narrow grip is pretty uncomfortable on the wrists for most people. A shoulder-width apart grip will help keep the proper form while being easy on your wrists.

Small Range Of Motion

You want to ensure you hit the full range of motion on every rep. A deeper range of motion will recruit more muscle fibers, leading to muscle growth. Every rep should have the same starting, transition, and finishing position.  

Skull Crusher: Muscles Worked

The skull crusher is an exercise for the triceps, but a few more muscles are in play during this exercise.

• Triceps: The skull crusher isolates all heads of the triceps, but the long head does most of the work for this exercise. The long head is the only head of the triceps that attaches to the scapula, so it takes priority in any movement with your arms overhead.
• Deltoids: The deltoids help stabilize the shoulder joint during a skull crusher. Since your arms are overhead, the delts are activated. By only hinging through your elbows during a skull crusher, the delts will play a role in stabilization.
• Upper Back: The upper back muscles help stabilize your body on the bench. Think of your lats as what glues you to the bench.
• Forearms: The forearm muscles must stabilize the weight, whether a barbell, dumbbell, or resistance band.

Skull Crusher Benefits

Stronger Triceps

The triceps are responsible for elbow extension, so the triceps are a massive factor during the lockout phase of a lift. Lifts like the bench press, overhead press, snatch, and split jerk all have a lockout phase where the triceps must be strong. Strengthening the triceps will strengthen the lockout, strengthening your primary lifts.

Curious about what other tricep exercises help with the bench press? Check out our article 16 Best Tricep Exercises To Increase Bench Press Strength.

Elbow Health

Strong triceps have a direct impact on elbow health. The elbow is a common joint for overuse injuries. Skull crushers strengthen the muscles and tendons in the elbow, which are susceptible to injury.

Aesthetics

For the everyday gym go-er, having bigger or more defined arms is typically the goal. The triceps make up most of your arm, so growing your triceps will make your arms more aesthetic.

Interested in the best ways to get bigger arms with a curl bar? Read more about the 14 Best Curl Bar Exercises (Plus, Sample Workout).

Tips For Skull Crushers

In this section, I will add a few pro tips from a strength and conditioning coach to make your skull crushers even more effective.

Set Your Shoulders

Set your shoulder blades before you start the movement while your arms are reached overhead. To do that, pinch your shoulder blades down and back. “Bend” the bar with your hands. You will feel your shoulders set before you have started doing a rep.

The benefit of doing this is that you can guarantee all of the focus will now be on your triceps. With your shoulders down and back, they will not roll forward as you press up. This will also help keep your elbows tight to your body.

Wrists Locked

As you lower the bar, make sure you keep your wrists locked. The weight should not pull your wrists down. That will be very uncomfortable and put a lot of stress through the wrist joint. You should always be able to draw a straight line from your knuckles down your forearm to the elbow joint.

Keeping your wrists locked will also keep constant tension on your triceps during the entire movement.

Add A Pause

Adding a 2-second pause at the bottom is a bit more advanced but will ultimately lead to more muscle gain. The pause will require you to generate more force to push the weight back to the top. Generating more force means activating more muscle fibers, and training more muscle fibers will lead to more strength gains in your triceps.

Remember that the pause at the bottom will require you to maintain proper form even more. Many people flare their elbows on the initial drive up from the forehead. Keep those elbows tight to your body and wrists locked as you add a pause to a skull crusher.

How To Add Skull Crushers To Your Workout

Frequency

Add skull crushers into your weekly workout routine 2-4 times weekly.

If triceps are your focus for the day, I recommend doing skull crushers at the beginning of your workout. This will allow you to achieve maximal growth before you become fatigued throughout the workout. If you are doing a push day and the triceps are more of an accessory muscle, you can do skull crushers anywhere in the workout.

Sets and Reps

Sets and reps will depend on your goals of doing skull crushers.

• Muscle Strength: 2-4 sets of 6-8 reps at a heavier weight
• Muscle Growth: 3-4 sets of 8-12 reps at a medium-heavy weight
• Muscle Endurance: 3-4 sets of 12-20 reps at a light-medium weight

Tempo

Tempo refers to the pace of the exercise. I always recommend doing a 3-second tempo on the eccentric or lowering the weight to your forehead. Slow eccentric movements allow for higher levels of muscle growth.

Progression

A few ways to progress skull crushers are increasing weight and tempo with the same weight.

If you can comfortably do all your sets and reps properly, I will always stress to increase weight. When you increase the weight, ensure the correct form is still being used.

Return to your original weight if it is difficult to get the correct form when increasing weight. Now, do a 4-5 second eccentric action. This longer tempo will make you work harder at the same weight. Over time, you will become stronger and will then be able to progress to a higher weight.

Variations of Skull Crushers

An easy way to add variation to a skull crusher is to change the piece of equipment, but you can also change the angle at which it is positioned.

• Dumbbells: Doing a skull crusher with dumbbells will require more stabilization with your shoulders because each arm will work independently. You can also adjust your grip with dumbbells, which can change how the tricep muscles are recruited.
• Resistance Bands: Resistance bands make the movement more difficult at the top because the band will be the most stretched out. This is good to work on the top lockout position of a skull crusher.
• Cable Machine: A cable machine provides constant tension throughout the entire range of motion, so your triceps will be worked throughout the movement.
• Decline Bench: Lay on a decline bench so your feet are higher than your head. You will get more of a stretch on the lateral head of the triceps.
• Incline Bench: A 30 ° incline bench will target the triceps’ long head because of the pull line.

Check out our article, 11 Best Long Head of the Triceps Exercises, to learn about other alternatives to target the long head.

Alternatives to Skull Crushers

As I said before, all 3 heads of the triceps are activated during a skull crusher, but the long head is the main driver. The 3 alternatives to the skull crusher that I listed all focus on the long head of the triceps.

Close Grip Bench Press

The close-grip bench press targets the pecs, front delts, and triceps. Unlike a traditional barbell bench press, close grip focuses more on the delts and triceps. With your hands closer on the bar, you have to keep your elbows tight to the body. Keeping your elbows tight will put a big stretch on the triceps and promote tricep growth.

One advantage of the close-grip barbell bench press is that you can overload the exercise with weight to grow your triceps.

Want more exercises to target the lateral head of the triceps? Read more about the 10 Best Lateral Head Tricep Exercises (That Actually Work).

Overhead Cable Extensions

The overhead cable extension is another tricep exercise for building size and strength. It completely isolates the triceps.

An advantage to using a cable for a standing overhead tricep extension is the pull from the cable stack. The direction of resistance will give constant tension on the triceps through the entire range of motion.

Tate Press

The Tate press is a tricep exercise that is not as common as others but certainly has its place. It is another tricep isolation exercise that puts a stretch on the long head. The Tate press offers a unique line of pull with the elbows pushed out wide.

The Tate press is done with dumbbells, so working through bilateral tricep strength differences is a good option.

pushing yourself out of a chair and vacuuming will become even easier with stronger triceps

FAQ

Are Skull Crushers a Push Exercise?

Yes, skull crushers are a push exercise. To be a push exercise, the concentric action has to be “pushing” the weight. The concentric phase of a skull crusher is to push the bar from the bottom to the top.

Are Skull Crushers Good for Abs?

Skull crushers are a strength-based exercise that isolates the triceps muscles in your arms. You will have to engage your core during a skull crusher.

What Is the Difference Between Skull Crushers and Lying Tricep Extension?

The main difference between skull crushers and lying tricep extensions is where you bring your hands. Your hands at the bottom position of a skull crusher will be right above your forehead. However, with a lying tricep extension, your hands will be behind your head, and your elbows will align with your forehead.

Are Skull Crushers More Effective When Done With a Barbell?

Barbells have both advantages and disadvantages when used for skull crushers, but barbells are more effective for developing strength. A barbell allows for more weight to be lifted compared to dumbbells. Using heavier weights will lead to increased strength.