Skull Crushers: Muscle Worked, How To Do and Form

Are you ready to make your tricep workout even better? Look no further than the well-known exercise called skull crushers.

Skull crushers are a classic triceps exercise that has been used by bodybuilders and strength athletes for decades.

It is one of the most common tricep isolation exercises out there and is typically performed on a flat bench using either an Ez-bar, straight bar or dumbbells.

You can also perform the skull crushers by changing the bench position either incline or decline, depending on the requirements.

In this article, we will look at the following:

  • What skull crushers
  • Which muscles worked during it
  • Their benefits and
  • How to perform them correctly,
  • How you can modify them based on available equipment

What are Skull Crushers

Skull crushers, also known as lying triceps extensions, are an isolation exercise that works the triceps brachii muscle. It works your triceps as your elbow bends and straightens, while your shoulder muscles stabilize your shoulder joint.

The name “skull crusher” comes from the exercise’s mechanics of bringing the weight down to your skull from an overhead position.

Barbell skull crushers are a popular type of skull crusher among gym goers as well as bodybuilders. There are many other variations of skull crusher that you can do to maximize the muscle stimulation.

If you do the skull crusher exercise wrong, you might hurt yourself. If done correctly, the risk is minimized and the result will improve.

Muscle Worked During Skull Crushers

Skull crushers primarily work the triceps brachii, with an emphasis on the long head of the muscle. The lateral and medial heads of the triceps are also engaged to a lesser degree.

The forearm muscles, specifically the brachialis, brachioradialis, Forearm Flexor muscles act as stabilizers during skull crushers, helping to maintain control and stability.

In addition to its target of the tricep, the skull crushers have the involvement of several synergist and stabilizer muscles, Pectoralis Major, Anterior Deltoid, Lats and Biceps Brachii.

Muscle Worked During Skull Crushers

Benefits of Skull Crushers

Skull crushers work the tricep muscle through a deep range of motion, which is great for building muscle. Furthermore, they do not put as much strain on the elbows as other tricep exercises.

There are numerous other benefits to performing skull crushers.

  • Skull crushers work the triceps, which will help protect your elbow joints in other settings.
  • It can help improve complex movements such as the bench press and add mass to the triceps.
  • Studies have shown that the triceps play a critical role in throwing movements. This resulted in enhanced overhead throwing power.
  • To do skull crushers, you need to move your arms to full range of motion. This can make your shoulders and elbows more flexible and move freely.
  • The skull crusher exercise can be a good alternative to the standing overhead triceps extension if you are experiencing pain or difficulty with overhead exercises.
  • A study conducted in 2020 revealed that a specific triceps exercise could enhance the strength of the bench press.
  • Strengthening your triceps is a great way to work on your functional fitness, and make sure that the work you do in the gym also benefits you in your everyday life.
  • Skull crushers offer versatility as it can be performed with either a dumbbell, barbell, or an EZ curl bar. Because of this adaptability, you can personalize the exercise.

How to Do Skull Crushers

If you are new to this exercise, you should start with a light weight and work on perfecting your form. As you get used to the exercise and get stronger, you can slowly increase the weight you use.

Here are the steps on how to do skull crushers:

  1. Lie down on a flat bench with your feet firmly planted on the ground.
  2. Make sure your head, upper back, and buttocks are in contact with the bench.
  3. Pick a weight, such as dumbbells or a barbell, for the workout. Choose the weight that is suitable for you.
  4. If using a barbell or EZ-curl bar, grip it with an overhand grip slightly wider than shoulder-width apart.
  5. If using dumbbells, hold them with a neutral grip (palms facing each other).
  6. Extend your arms straight above your chest, perpendicular to the floor.
  7. Bend your elbows and slowly lower the weight towards your forehead.
  8. Control the movement and aim to bring the weight to a point just above your forehead without touching it.
  9. Pause briefly at the bottom position, feeling the stretch in your triceps.
  10. Then lift the weight back up by extending your elbows until your arms are fully extended. Don’t lock your elbows at the top.
  11. Perform 3-4 sets of 8–12 repetitions.
How to Do Skull Crushers

Tips For The Proper Form Of Skull Crushers

When you do a skull crusher exercise, you should pay attention to these things.

  • Avoid lowering the weight too close to your face or forehead. This can put too much strain on the elbows and increase the risk of getting hurt.
  • The entire movement should be performed slowly and with control, especially when the weight is moving behind the head.
  • Focus on your breathing. Exhale as you lift the weight back up, and inhale as you lower it down towards your forehead.
  • Keep your elbows close to your head and pointing upward.
  • Keep your shoulders and upper arms fixed. All the movement should be in your elbows.
  • Prevent your elbows from flaring out to maintain proper form.
  • Don’t lock your elbows at the top of the movement. This can put stress on your elbows and lead to injury.
  • Pause for a moment at the bottom of the movement. This will help to stretch the triceps and get a better workout.
  • Start light, add weight gradually, and always keep the movement under full control.
  • If using a barbell or EZ-curl bar, grip it with an overhand grip slightly wider than shoulder-width apart. If using dumbbells, hold them with a neutral grip (palms facing each other).

Sets and Reps

When you want a great pair of triceps, you definitely want to train your tricep for both strength and hypertrophy. The skull crushers are the best tool for strengthening the tricep because you can load the most weight.

­For this goal, you should combine skull crusher with tricep dips, tricep push down and overhead tricep extension.

Of course, the number of sets and reps will be determined based on your fitness journey. A variety of sets and reps builds tricep strength and muscle.

1. Muscle Growth

The research has shown that higher intensity exercises with moderate repetitions and sets build muscle by recruiting a higher number of muscle fibers.

  • Sets: 3 to 4 sets
  • Reps: 8 to 12 reps
  • Weight selection: That becomes difficult to complete the last few reps with proper technique.
  • Rest between sets: 60 to 90 seconds

2. Endurance

To enhance muscular endurance, focus on higher repetitions with lighter weights and minimal rest.

  • Sets: Perform 3 to 4 sets of dumbbell skull crushers.
  • Repetitions: Aim for 15 to 20 reps per set.
  • Weight selection: That allows you to complete the desired repetitions without compromising your form.
  • Rest between sets: 30 to 45 seconds.

Best Skull Crusher Variations

There are many variations of skull crusher that you can do with dumbbells, cable a standard barbell, or by changing bench position.

The skull crusher can be done in different ways to suit your fitness level.

  • If you are new to performing skull crusher, you may want to apply a few modifications to make the exercise easier. One way to counter this problem is to use a lighter weight. Another is to dumbbell and cable skull crunches.
  • If you are looking for a more advanced variation to stimulate different muscle fibers in the tricep, then try Incline and decline Skull Crushers.

Below you will find 6 skull crusher variations that can be used by coaches and athletes in order to keep training varied and progressive.

1. Barbell Skull Crushers

The barbell skull crusher is a popular variation of the skull crusher exercise that targets the triceps muscles.

The barbell allows you to handle heavier weights compared to other variations, leading to greater strength gains and muscle stimulation.

Having stronger and bigger triceps is not only important from an aesthetic standpoint, but can also help contribute to better performance on pressing motions such as the bench press.

Barbell Skull Crushers

How To Do Barbell Skull Crunches

  1. Lie down on a flat bench, spread your legs, and plant your feet flat on the floor for stability.
  2. Grasp the barbell about shoulder-width apart with your hands and your thumbs wrapped around the bar.
  3. Extend your arms straight above your chest, perpendicular to the floor.
  4. Keep your elbows stationary and slowly lower the barbell towards your forehead by bending at the elbows.
  5. Hold for 1–2 seconds when the barbell is close to your forehead.
  6. Exhale as you press the barbell back up to the starting position.
  7. Repeat for the prescribed number of repetitions.
Know More: 7 Best Barbell Triceps Exercises For Mass And Strength

2. Incline Skull Crushers

The incline skull crusher helps to build muscle and strength in all three tricep heads.

The incline position allows for a deeper stretch of the triceps during the eccentric (lowering) phase and a more intense contraction during the concentric (lifting) phase.

Adding incline skull crushers to your tricep workout routine can help you get stronger and overcome plateaus.

Incline EZ Bar Skull Crushers

How To Do Incline EZ Bar Skull Crushers

  1. Set an incline bench at around 30-45 degrees.
  2. Take an EZ Bar and lie down on a bench with your face facing up and your feet on the floor.
  3. Extend your arms over your shoulders with your palms facing up.
  4. Then slowly lower the weight towards your forehead by bending your elbows.
  5. Hold this position for a count and then with a controlled motion raise your arms back up to the starting position.
  6. Repeat for as many reps and sets as desired.

Tips For Proper Form

  • Keep your upper arms fixed, with your elbows close to your head.
  • Do not use excessively heavyweight as this is dangerous for your elbows.

3. Decline Skull Crusher

Decline skull crushers are a variation of the traditional skull crusher exercise performed on a decline bench.

The decline angle enhances the stretch on the triceps during the eccentric phase and allows for a deeper contraction during the concentric phase. This increased range of motion can lead to greater muscle activation and development.

Decline Skull Crusher

How To Do Decline Skull Crushers

  1. Grab a barbell and lie against a decline bench with your feet firmly on pads.
  2. Extend your arms over your shoulders with your palms facing up, and then slowly lower the barbell behind your head by bending your elbows.
  3. Hold this position for a count. Then, in a controlled motion, raise your arms back up to the starting position.
  4. Repeat for as many reps and sets as desired.

Tips For Proper Form

  • Keep your upper arms fixed, with your elbows close to your head.
  • At the top of the movement, do not lock out your elbows.

4. Lying Cable Skull Crusher

Unlike other variations of skull crushers that rely on gravity, lying cable skull crushers maintain constant tension on the triceps throughout the entire range of motion.

The cable rope overhead skull crushers exercise forces you to keep tension on the cables throughout the range of motion, which works your triceps from start to finish.

There are several variations of cable skull crushers that you can incorporate into your triceps workout routine.

  • Single-arm cable skull crushers
  • Rope cable skull crushers
  • Reverse Grip Skull crusher
Cable Skull Crusher.

How To Do Lying Cable Skull Crusher

  1. Position a bench close to a low cable pulley, with the head of the bench nearest to the pulley.
  2. Lie on your back (supine) on the bench. Grasp the bar with a shoulder-width pronated (overhand) grip.
  3. Press the bar upward until your arms are fully extended, and hold the bar over your forehead so that your arms are slightly slanted backwards.
  4. Keeping your elbows in, inhale as you flex your elbows and lower the bar to your forehead.
  5. Exhale as you extend your elbows to raise the bar back to the starting position.
  6. Repeat for the prescribed number of repetitions.

Tips For Proper Form

  • Ensure that the cable is taut throughout the repetition.
  • Use a wavy bar if the straight bar is hard on your wrists.
  • Keeping your elbows in will prevent the involvement of your pectorals and anterior deltoids and keep the emphasis on your triceps brachii.

5. Dumbbell Skull Crusher

Dumbbell skull crusher is a popular exercise that primarily targets the triceps muscles. It allows you to work each arm independently, which helps to correct muscle imbalances and ensure balanced triceps development.

Dumbbells also allow you to adjust your grip and range of motion based on your comfort and flexibility.

Dumbbell Lying Triceps Extension

How To Do Dumbbell Skull Crusher

  1. Lie on a flat bench with your feet flat on the floor.
  2. Grasp a dumbbell in each hand and hold them directly above you with your palms facing inward (neutral grip) and your arms extended.
  3. Making sure that your upper arms and elbows are still, lower the dumbbell behind your head, feeling a stretch in your tricep muscles.
  4. Pause and squeeze the triceps, and then raise the dumbbells back to the starting position.

Tips For Proper Form

  • Concentrate on keeping your elbows stable.
  • Do not allow your elbows to flare out to the sides.
  • Slowly lower the weights and do not use momentum.
Know More: 10 Best Dumbbell Triceps Exercises for Mass & Strength

6. Reverse Grip Skull Crushers

Reverse skull crushers are a remarkable tricep exercise because they encourage you to keep your elbows tucked in rather than flared out.

While this elbows-in lifting technique certainly trains the triceps well, performing reverse grip skull crushers is actually very dangerous unless you use lifting straps or Versa Grips to keep the bar secure.

Reverse Grip Skull Crusher

How To Do Reverse Grip Skull Crushers

  1. Grab the bar with a supinated grip and wrap your lifting straps securely around the bar.
  2. Lie back on the bench and press the bar up so that it’s positioned over your forehead.
  3. Lower the bar behind your head by breaking at your elbows.
  4. Allow enough backward shoulder movement to get an intense stretch in the long (inner) head of your triceps.
  5. Reverse the motion by extending your elbows until they reach complete lockout.
  6. Repeat for as many reps and sets as desired.

Tips For Proper Form

  • This exercise is best when using an EZ bar because it’s much easier on the wrists when using a reverse grip.
  • Keep your elbows in throughout the set and don’t allow them to move forward or back as you raise the weight.
  • Keep your rep timing slow and control the weight on the way down.

Skull Crushers Alternatives

Below are three skull crushers alternatives coaches and athletes can use to increase triceps strength and size.

1. Parallel Bar Triceps Dip

Parallel Bar triceps dips are one of the most effective compound movements for the upper body pushing muscles – the chest and triceps especially. It is another good example of compound exercise of the tricep.

When performed on a narrow parallel bar with elbows back and your torso upright, the dip becomes one of the best exercises for building triceps mass.

Parallel Bar Triceps Dip

2. Two Arm Dumbbell Extension

The seated dumbbell tricep extension is one of the best alternate of skull crusher. It is an exercise used to isolate the muscles of the triceps.

Overhead extension exercises are particularly useful in targeting the long head of the triceps muscle. Having a larger and denser long head will give you an overall appearance of a larger tricep.

Two Arm Dumbbell Extension

3. Triceps Pushdown

Triceps Pushdown provides a uniform resistance throughout the movement, unlike barbell or dumbbell exercises, where the resistance varies during the lift.

Using the straight bar, a pronated grip (palms down) emphasizes the outer lateral head of the triceps, whereas a supinated grip (palms up) focuses effort on the inner long head.

An angled V-shaped bar switches the hands into a neutral grip (thumbs up), equally targeting all three triceps heads.

Triceps Pushdown

Frequently asked questions 

What muscles do skull crushers work?

The skull crusher is an isolation exercise that works the triceps muscle group in the back of the upper arm. The triceps, as the name implies, is a muscle with three heads.

Are skull crushers good?

The Skull Crusher is a great triceps exercise that can be done at the gym. And you can also do the dumbbell skull at home with a pair of dumbbells. The DB skull crusher is a more difficult variation of the classic skull crusher.

Skull crushers hurt my elbows. What should I do?

I doubt they are skull crushers. If you are experiencing any pain, you should seek medical attention immediately. However, it is a good rule of thumb that you should avoid something if it hurts, even if it is not typical muscle soreness from a workout. You could also try variations of cable exercises, like push downs. These kinds of movements tend to be easier on the elbow and shoulder joints.

How much weight should I use for Skull Crushers?

Start with a light weight and build up over time. Make sure you focus on form and technique first.

You should also give your shoulders, wrists, and forearms time to develop their strength.

Can you do Skull Crushers without a bench?

Yes, you can perform skull crushers without a bench by lying down on the floor.

Do skull crushers build mass?

Skull crushers combined with pressing movements help us build bigger arms and get balanced muscle growth. The skull crusher is an effective way to work all three heads of your triceps.


Skull crushers are an excellent exercise to build mass and strength in your triceps. They’re also an excellent way to work on stability in your shoulders.

There are many ways to do this exercise, so you can choose the best skull crushers variation for you. Mastering the skull crusher will help you see gains across many muscles in your upper body.


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  3. Alves D, Matta T, Oliveira L. Effect of shoulder position on triceps brachii heads activity in dumbbell elbow extension exercisesJ Spors Med Phys Fitn. 2017;58(9):1247-52. doi:10.23736/s0022-4707.17.06849-9
  4. Shuttlewood K, Beazley J, Smith CD. Distal triceps injuries (Including snapping triceps): A systematic review of the literatureWorld J Orthop. 2017;8(6):507-513. doi:10.5312/wjo.v8.i6.507
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