The Skull crushers workout is an excellent way to add definition and mass to the back of your arms (tricep). And with common-sense and good foam, you can perform them safely with minimal risk of injury.
Skull crusher is one of the most common tricep isolation exercises out there and are typically performed on a flat bench using either an Ez-bar, straight bar or dumbbells. You can also change the bench position either incline or decline as per requirement.
In this article, we will look what skull crushers are, which muscles worked during the workout, how to perform them correctly, their benefits, and how you can modify them based on available equipment and your ability.
What are skull crushers
Skull crushers aka supine or lying triceps extensions work 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 variation of skull crushers, an exercise popular among average 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 perform the skull crusher exercise incorrectly, there is some degree of risk of injury. However, when performed correctly, the risk is minimized and the result will improve.
Muscle Worked During Skull Crushers
The skull crushers Primary Muscle Worked, the Triceps brachii. In addition to its target, the tricep. The skull crushers have the involvement of several synergist and stabilizer muscles, Pectoralis Major, Anterior Deltoid, and Biceps Brachii.
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.
- 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.
- 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.
Barbell Skull Crushers Guide
The barbell skull crusher is an exercise used to strengthen the muscles of the triceps.
The triceps can be trained in many ways to promote growth and overhead extensions, such as the lying barbell skull crusher, are an effective way to target the long head of the tricep.
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.

How To Do Barbell Skull Crunches
- Lie supine (on your back) on a flat bench, spread your legs, and plant your feet flat on the floor for stability.
- Grasp the barbell about shoulder-width apart with hands and your thumbs wrapped around the bar.
- Unpack the bar, with your arms fully extended overhead, tuck your elbow 45 degrees from your sides towards your feet.
- Now begin bending your elbows and lowering the bar towards your chin/neck with control until your forearms and biceps touch.
- Exhale as you press the barbell back up to the starting position. Repeat for the prescribed number of repetitions.
The best tip and technique for doing skull crushers
When it comes to getting your form right during this exercise, there are a few things you should watch out for:
- You should never lower the weight towards your forehead or skull. The weight travels behind the head.
- The entire movement should be performed slowly and with control, especially when the weight is moving behind the head.
- This exercise requires practice. Start light and increase weight as you master proper form.
- Keep your elbows high and approximately 45 degrees out to your sides.
- Keep your shoulders and upper arms fixed. All of the movement should be in your elbows.
- Prevent your elbows from flaring out to maintain proper form.
- Start light, add weight gradually, and always keep the movement under full control.
How to train your triceps (Sets & 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. Tricep muscle and strength is built in a variety of set and rep ranges.
Sets
- Beginners: ~10 sets per week.
- Intermediate: ~15 sets per week.
- Advanced: ~20 sets per week.
Reps
- 3 to 5 reps for power
- less than 6 reps for strength
- 6 to 12 reps for hypertrophy
- 12 to 20+ reps for endurance
The load should bring you to or near failure within the given rep ranges for the workout to be effective.
Start with just a few reps of this exercise. Once you have begun to develop strength, work your way up to performing 3 to 5 sets of skull cruncher, each with between 6 and 12 repetitions. If using a barbell, have a spotter available in case you run into difficulty.
Best skull crusher Variations
There are many variations of skull crusher that you can do with dumbbells, cable a standard barbell, or by change 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 chest, then try Incline and decline Skull Crushers.
Below are four skull crusher variations that can be used by coaches and athletes to keep training varied and progressive.
1. Incline EZ Bar Skull Crushers
The incline EZ Bar skull crusher help to build muscle and strength in all three tricep heads.
It can be used by both those looking to build bigger triceps and those looking to increase their tricep strength.
The benefit of doing these movements is that you can achieve a deeper stretch in the muscle, which may help activate more muscle fibers.

How To Do Incline EZ Bar Skull Crushers
- Grab an EZ Bar and lie against an incline bench, face up, with your feet firmly planted on the floor.
- Extend your arms over your shoulders with your palms facing up, and then slowly lower the barbell behind your head by bending your elbows.
- Hold this position for a count and then with a controlled motion raise your arms back up to the starting position.
- Repeat for as many reps and sets as desired.
Tips
- Keep your upper arms fixed, with your elbows close to your head.
- Do not use excessively heavyweight as this is dangerous for your elbows.
2. Decline Skull Crushers
The decline skull crusher is a variation of the lying dumbbell tricep extension that adds a slight decline to the movement.
It is an isolation exercise that builds muscle and strength in all three tricep heads.

How To Do Decline Skull Crushers
- Grab a barbell and lie against a decline bench with your feet firmly on pads.
- Extend your arms over your shoulders with your palms facing up, and then slowly lower the barbell behind your head by bending your elbows.
- Hold this position for a count. Then, in a controlled motion, raise your arms back up to the starting position.
- Repeat for as many reps and sets as desired.
Tips
- Keep your upper arms fixed, with your elbows close to your head.
- At the top of the movement, do not lock out your elbows.
3. Lying Cable Skull Crusher
Cable rope overhead skull crushers exercise forces you to keep tension in the cables throughout the range of motion, engaging your triceps from start to finish.
Use a cable machine and a double-handled rope attachment to work both triceps at once in a power set.

How To Do Lying Cable Skull Crusher
- Position a bench close to a low cable pulley, with the head of the bench nearest to the pulley.
- Lie on your back (supine) on the bench. Grasp the bar with a shoulder-width pronated (overhand) grip.
- 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.
- Keeping your elbows in, inhale as you flex your elbows and lower the bar to your forehead.
- Exhale as you extend your elbows to raise the bar back to the starting position.
- Repeat for the prescribed number of repetitions.
Tips
- 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.
4. Dumbbell Skull Crusher
The dumbbell lying triceps extension (Aka Dumbbell Skull Crusher) is an excellent move to begin your dumbbell triceps workout routine. Triceps extensions are isolation exercises, which means they use just one joint.
Triceps extensions can be beneficial for fixing imbalances in the triceps or rehabilitating from injury. It put no pressure on the wrists, so they are an alternative for people with wrist strain or injury.

How To Do Dumbbell Skull Crusher
- Lie on a flat bench with your feet flat on the floor.
- Grasp a dumbbell in each hand and hold them directly above you with your palms facing inward (neutral grip) and your arms extended.
- Making sure that your upper arms and elbows are still, lower the dumbbell behind your head, feeling a stretch in your tricep muscles.
- Pause and squeeze the triceps, and then raise the dumbbells back to the starting position.
Tips
- 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.
5. 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.

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

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.

3. Triceps Pushdown
Triceps Pushdown is also known as triceps Pressdown, is the best triceps exercise. The cable 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.

Takeaways
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.
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 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.