This definitive guide will teach you everything you need to know about the Skull Crushers exercise.
What are Skull Crushers?
Skull Crushers are a barbell exercise performed on a bench that primarily work and strengthen the triceps.
The movement involves lowering the load downwards towards the head then propelling it with force back upwards.
- What are Skull Crushers?
- Muscles Worked by Skull Crushers
- Benefits of Skull Crushers
- How to do Skull Crushers
- Technique Tips
- Who are Skull Crushers For?
- Skull Crushers Reps and Sets
- Skull Crushers Mistakes
- Skull Crushers Alternatives
- Skull Crusher Variations
- What are Skull Crushers Good For?
- Is Skull Crusher a Good Exercise?
- What Exercises Hit all Three Heads of Triceps?
- How Much Weight should I Use for Skull Crushers?
- Why are Skull Crushers so Hard?
- What Bar is used for Skull Crushers?
- Can you do Skull Crushers with a Barbell?
- Are Skull Crushers Bad for Shoulders?
- Can you do Skull Crushers without a Bench?
- Learn More
Muscles Worked by Skull Crushers
Skull Crushers predominately target the triceps.
These muscles are responsible for elbow extension. During the full range of motion for this exercise they are isolated through deep elbow flexion.
Scapular Stabilisers and Rear Deltoids
These muscle groups must work to control and balance the movement. They have to support the shoulder socket to enable the elbows to stay in a fixed position throughout every rep.
Wrists and Forearms
Skull Crushers also place stress on the wrists and forearms. This strengthens and enhances them to become more resilient.
Benefits of Skull Crushers
There are many benefits to this effective exercise.
Skull Crushers are a key exercise for strengthening your triceps. They will isolate and improve this important muscle group.
When trained in a hypertrophy context, they are a great tool for growing larger triceps.
Triceps account for around two thirds of the size of your arms but most people make the biceps the primary focus for arms training. When you do the maths, this doesn’t make sense.
Better Lockout Strength
Stronger, more powerful triceps will make it easier to lockout pressing exercises such as the Bench Press, Overhead Press, Jerk, Floor Press and many others.
The tougher and more resilient your triceps, the higher your PRs will be.
Improved Elbow Health
Poor joint health (common for lifters in the knees, hips, shoulders and elbows) is often a more regular occurrence than it should be.
Building up functional strength gradually over time, performing proper recovery practices, good nutrition and warming up intelligently are all excellent practices for keeping these parts of your body safe and strong.
They are great because they work the tendons, connecting tissues and ligaments under a lighter weight (than a Close Grip Bench Press for example) and so help them improve as well.
How to do Skull Crushers
These instructions are for the exercise performed with an EZ bar on a bench.
- Lie back on the bench. Plant your feet into the ground and create a stable base with your entire body
- Hold the EZ bar with a pronated grip (palms facing downwards) on the narrow part of the handles
- Extend your arms fully. Balance the weight above your chest
- Inhale and brace your core, glutes and grip as tight as you can
- Slowly bend at the elbows and lower the weight down to the forehead
- Pause and squeeze the triceps. Push the arms back up to the starting position. Exhale
- Repeat for the desired number of reps
Pin the Elbows in a single place. Make sure that the elbows move as little as possible during the movement. Image that you must fix them in one spot and not let them deviate.
Grip the barbell as tight as you can. This will help you generate more strength and engage your muscles properly.
Control the barbell at all times. If you can’t move the bar slowly, with purpose and control at all times then lower the weight.
Adjust the movement. With Skull Crushers many athletes like to change the lowest position. Some prefer lowering to the forehead while others want to lower behind the head for a fuller stretch and stimuli. Do what works best for you.
Bar Path. Follow the same trajectory for the bar during both the concentric and eccentric portion of the lift.
Who are Skull Crushers For?
The short answer is everyone.
However, they can be used in different ways to achieve a spectrum of different goals.
Scroll through and find out how you should add them into your training based on your discipline and goals.
The movement is a perfect isolation exercise for the triceps, building muscle mass and definition.
They are a great addition to follow bigger movements such as the Bench Press variations (flat, incline, decline and close grip) or weighted dips in an upper body / triceps session.
The exercise can also be used as an excellent finisher to completely destroy your triceps at the end of a session.
Strength and Functional Fitness Athletes
Use the movement to augment lockout pressing strength, for arm strength in general and for the overall health of your elbows.
Skull Crushers Reps and Sets
This section will teach you how many reps and sets to do to achieve your goal.
To Build Muscle
Go for 3 – 4 sets of 10 – 12 reps. Keep rest periods short, 30 – 45 seconds and certainly no more.
In each set the last few reps should be very close to failure.
Concentrate on the descent and maximising time under tension as this is what will really optimise your gains.
To Improve Strength
Program 3 – 5 sets of 6 – 8 reps. Rest for up to three minutes. Take your time hear and focus on slow movements and perfect form.
Skull Crushers Mistakes
Make sure you aren’t making any of these common mistakes.
Moving the Bar too Quickly
Make sure you lower the bat slowly. You want to have as much time under tension as possible if your goal is hypertrophy.
Moving the Elbows
The Elbows must be pinned in the same place and should move as little as possible throughout the full range of motion.
Keep them tight into the body and don’t let them flay outwards.
Using a Weight that is Too Heavy
They are not an exercise that you are trying to PR. Keep the weight lighter as this will also benefit your elbow health, tendons, ligaments and connective tissue.
Skull Crushers Alternatives
If you want a similar stimulus then add these variations into your upper body training.
A classic bodyweight exercise that is highly effective for developing stronger, more muscular triceps.
Try strapping on a weight to add stress. Pause dips are another great way to maximise their positive impacts.
Overhead Triceps Extension
This variation can be performed with a cable, barbell, dumbbell or kettlebell.
It is another useful triceps isolation exercise for bigger, stronger arms?
Close Grip Bench Press
A great upper body barbell exercise for improving your triceps, this allows you to load up your arms and push hard.
The narrow grip on the barbell forces the elbows close into the sides of the body and forces the triceps to work hard.
Skull Crusher Variations
Add these variations into your program to keep your body guessing and your training varied and challenging.
These variations also allow you to perform the exercise even if you don’t have access to a bench or EZ bar.
Floor Skull Crushers
The technique is the same as the standard version however you simply lie on the floor instead of the bench.
You will not be able to achieve the same full range of motion but at least you can get the reps in.
Dumbbell Skull Crushers
These can be done on the floor or on a bench.
Hold the dumbbells with a neutral grip (palms facing each other). You can use this variation to work the triceps unilaterally as well which is a decent benefit.
If you have any muscular imbalances then this variation can help you counter them.
It also allows for deep elbow elbow flexion which is useful for hypertrophy.
Here you can also use any different load. The altered angle of the bench which change the stimulus.
Experiment with different angles to find the best set up for you.
These are also knowns as negative reps. They are a highly effective asset to any hypertrophy plan.
You need a spotter to complete this technique. You can perform it when your arms are too tired to even lift the weight back to the starting position.
The spotter lifts the weight to the starting position and makes sure the load doesn’t crash down as you slowly lower it. Your job is to control it and get even more time under tension, even when you are too fatigued to lift the weight at all.
This will take you to complete fatigue and optimise gains.
Got further questions? Scroll through our FAQs.
What are Skull Crushers Good For?
They are good for developing strong, muscular triceps.
They also strengthen your elbows, ligaments, tendons, connective tissues and augment pressing and lockout power for other lifts such as the Bench Press, Overhead Press and Jerk.
Is Skull Crusher a Good Exercise?
Yes, they are a great exercise to add into your arm, upper body and triceps training.
They can easily be programmed in many different ways to help accomplish varying goals.
What Exercises Hit all Three Heads of Triceps?
Diamond Push ups, Close Grip Bench Presses, Tricep Kickbacks, Skull Crushers and Tricep Pushdowns are all excellent ways to hit all three heads of the triceps.
How Much Weight should I Use for Skull Crushers?
Go lighter than you think when you start. It is important to allow your tendons and ligaments to grow strong as well in order to avoid injury.
Why are Skull Crushers so Hard?
They are hard because they isolate the triceps, are difficult to cheat and require a slow, controlled movement.
The lifter cannot power their way through using momentum and poor form.
What Bar is used for Skull Crushers?
Usually, the EZ bar is used but a barbell, dumbbells or kettlebells can also be used effectively and produce a great stimulus for the body and triceps.
Can you do Skull Crushers with a Barbell?
Yes, you can use a barbell for the exercise. The same rules apply. The lifter must fix their elbows in space, keep them tucked in, move slowly, control the load and breathe correctly to maximise the effects of the exercise.
Are Skull Crushers Bad for Shoulders?
No, the exercise is not bad for the shoulders.
Make sure that the weight is not too heavy, that you don’t have any pre-existing or current shoulder injuries and that you use correct form.
Keep the elbows close to the body as well to maximise the effectiveness of the exercise and minimise the chance of injury.
Can you do Skull Crushers without a Bench?
Yes, you can perform the exercise on the floor without a bench. The same rules apply in regards to form and speed.
Remember that the movement will have a slightly reduced range of motion as well.