How To Do Barbell Skull Crushers? Proper Form, Technique, Variations, And Benefits

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If you are looking for a good triceps exercise, consider barbell skull crushers. This funnily named exercise is a wonderful addition to your triceps toolset if you want bigger arms and better bench numbers.

Make yourself comfortable – in this article, we’ll be going over the benefits, proper form, common mistakes, variants, and alternatives of the barbell skull crusher! 

Which Muscles Are Worked By Skull Crushers?

The barbell skull crusher is an isolation exercise that targets the triceps. In case you didn’t know, the role of the triceps is to extend the elbow joint.

The triceps has three heads – long, medial, and lateral – and skull crushers load them all. However, the emphasis is more on the lateral and long heads of the muscle – the two triceps heads that we can see easily. Different variations of skull crushers may be used to shift emphasis to specific heads of the triceps.

Aside from the triceps, skull crushers load a whole bunch of other muscles for stabilization purposes. These include your chest, shoulders, lats, and even legs (since you use your legs for support).

Skull crushers won’t strengthen these supplementary muscles much. But if you have weaknesses, imbalance, or aches in supporting muscles, your performance in skull crushers may be compromised.

Benefits Of Skull Crushers

Why add skull crushers to your triceps routine? Well, here are a few reasons!

1. Stronger triceps

First up, skull crushers make your triceps stronger. Many exercises incorporate your triceps – like the shoulder press, bench press, or dips – but only a few bombard the triceps as hard as skull crushers.

Definitely give skull crushers a try if you:

  • Want to make your triceps stronger. Stronger triceps can increase your numbers in movements like the bench press or dips. Weak triceps muscles can undoubtedly hold you back in these exercises, so targeted training may be a good idea.
  • Want to make your arms bigger. Well-developed biceps muscles are considered the basis of arm size and beauty, but you should know that the triceps has a much bigger (pun intended) role in arm size. It makes up roughly two/thirds of the arm’s muscle mass, after all! So if you want bigger and better-rounded arms, don’t forget your triceps.

2. Improved lockout

Thanks to their emphasis on the triceps, skull crushers could help you improve your lockout. You can employ any other triceps exercise to fix lockout issues, but given the simplicity and accessibility of skull crushers, they are the right pick for many people.

3. Low injury risk

If we put aside that “skull crusher” thing, barbell skull crushers have a low injury risk, especially if you use an EZ bar or a triceps bar.

The elbows and wrists are loaded minimally and are placed at fairly comfortable angles, so as long as you don’t have any pre-existing pain in these areas, skull crushers should not injure them.

As for the “skull crusher” aspect, you are very unlikely to drop the bar onto your head if you pick weights reasonably and don’t push yourself too hard. A spotter for skull crushers is a good idea as well since dumping the barbell can be hard if you are alone.

4. Accessibility

Finally, I think another great thing about skull crushers is that they are accessible.

You can find a barbell in pretty much any gym, whereas good cable machines (albeit rather common) may be a unicorn in some areas.

Besides, if you have a home gym, you likely have a barbell.

All in all, barbell skull crushers are more accessible to the masses. If you don’t have access to a cable machine to do your favorite triceps extension, skull crushers are an excellent alternative.

How To Do Skull Crushers Correctly

Skull crushers are no rocket science – they are easy to grasp and do. Though if you don’t understand the movement well, it’s also easy to do wrong (more a little later).

Anyway, here’s how you do skull crushers:

  1. Lift the loaded barbell off the ground and carefully lie down on a bench. If you are going to have a training buddy, you could skip this step and ask them to lower the barbell onto your hands once you are on the bench.
  2. Hold the barbell above your chest, with your elbows extended.
  3. Keep your body tight and support yourself with your legs. This will prevent rocking and instability.
  4. Inhale.
  5. Holding your elbows perpendicular to the ground, bend your arms and lower the bar to just above your forehead. Don’t drop the weight – control it to avoid injury and improve the quality of the movement.
  6. As you exhale, squeeze your triceps muscles to lift the barbell back onto extended arms.


Note that you may use a regular straight bar, EZ bar, or a triceps bar. In its simplest form, barbell skull crushers are done with a straight bar.

If you feel confident, you could also lower the barbell further behind your head, giving your triceps muscles a good stretch and increasing the exercise’s range of motion.

To do this, you may have to bring your elbows slightly toward your head. But unless you are very good with vanilla skull crushers, don’t lower the bar behind your head.

Common Barbell Skull Crusher Mistakes

The barbell skull crusher is far simpler than a compound exercise like the bench press, but newbies can still do many things wrong. Below is my list of 4 very common mistakes that you should be avoiding with barbell skull crushers.

Excessive movement in the elbows

Traditional skull crushers require that you keep your elbows perpendicular to the ground through the entire range of motion. This allows you to increase the impact of the exercise on the triceps and minimize the involvement of secondary ones.

If you can’t fix the position of your elbows, the weight you picked is most likely too heavy, and your body is trying to compensate for this by bringing stronger muscles into the game. Drop the weight, and you should be able to fix this issue.

Elbows flaring out

Your elbows should move minimally in the horizontal plane – that is, they should not flare out. This is to keep your joints safe and make sure that your triceps are maximally loaded.

When your elbows flare out, the motion sort of becomes a bench press. With that, if your elbows are flaring out, the weight is too heavy. To keep the load in your triceps, choose your load carefully.

Excessively wide grip

Narrow to mid-width grips work the best for skull crushers. If you grip the barbell too wide, you may be unable to prevent your elbows from flaring out. Besides, a wider grip would twist your wrists as you lower the weight, possibly increasing the risk of injury.

With that, if skull crushers don’t feel comfortable to you, try a narrower grip.

Not controlling the weight

If you don’t want skull crushers to become true to their name, you should lower the bar toward your forehead in a controlled fashion. As I mentioned earlier, this would minimize the risk of injury and allow you to work the muscle better.

If you physically struggle to control the weight, again, pick a lighter load.

Barbell Skull Crusher Variants

If straight bar skull crushers don’t quite work for you or you want something slightly different, here are a few variations to try out!

EZ-bar skull crushers

Many people will agree with me – a straight bar isn’t the best for skull crushers. Primarily, this is because the straight bar keeps your hands in an uncomfortable position.

The solution is pretty easy – switch to an EZ bar! An EZ bar makes the exercise easier on the wrists, and it also allows you to minimize flare-outs.

45-degree skull crushers

Rather than keep your elbows perpendicular to the ground, bring them closer to your head to make a 45-degree angle. This will allow you to lower the bar behind your head, and it will also keep the triceps under constant tension because there is no resting point on top.

Smith skull crushers

If you don’t feel comfortable when a heavy bar gets within an inch of your head, you could try Smith skull crushers.

The muscle emphasis of this exercise is similar to that of the regular skull crusher, but you’ll have to slightly adjust the position of your elbows.

Since the trajectory of the bar in a Smith machine is constrained, you may need to shift your elbows back and forth to be able to perform the exercise comfortably. This is fine for Smith skull crushers.

You may also play with your positioning – e.g., lie closer to the machine – to see how it affects your training.

Barbell Skull Crusher Alternatives

If you don’t want a bar at all, here are 3 skull crusher alternatives.

Dumbbell skull crushers

Try dumbbells! Dumbbell skull crushers are done exactly the same way as barbell skull crushers, but they are more comfortable and easier on the joints.

Besides, since your arms aren’t connected by a barbell, identifying and fixing triceps imbalances becomes super-easy with dumbbell skull crushers.

Cable skull crushers

Another good option is the cable skull crusher. Since the line of pull comes from the side, cable skull crushers put the triceps under constant tension.

To do cable skull crushers, you need a cable machine with adjustable pulleys. Lower the pulley to its bottom position, get a bench, and grab the handle to begin! Note that with cable skull crushers, the exercise starts at the bottom – that is, you start pulling up from below rather than the other way around.

Overhead triceps extensions

Finally, try triceps extensions. This exercise is super-versatile – it may be performed seated, standing, with dumbbells, or with a barbell. Watch the video above to find out how to perform overhead triceps extensions!


You should now be able to perform textbook skull crushers! Remember these key points:

  • Minimize movement in your elbows.
  • Don’t allow large muscles to take away the load from the triceps.
  • Don’t load the barbell too heavily.
  • Keep the weight under control at all times.
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Jessica Carter
Jessica Carter
Jessica is an AFLCA certified personal trainer and holds a Masters degree in physical therapy from the University of British Columbia. She has been working in the field for 5 years and writes as a freelance about all things fitness related.