The Dumbbell Skull Crushers

If you struggle to perform the skull crusher with a straight or EZ barbell, then switching to dumbbells is a great idea. Besides, if you’ve never done skull crushers, dumbbells are great for getting started.

But how to do the dumbbell skull crusher correctly, and why even incorporate this exercise into your workout? Read on to find out!

What Are The Muscles Worked By The Dumbbell Skull Crusher?

The dumbbell skull crusher is an isolation exercise and is aimed at hitting the triceps muscle. Skull crusher is known to hit all the triceps heads in their entire length – all the way from the elbows to the lats. You may even target specific triceps heads by slightly modifying the exercise – more on that later!

Aside from the triceps, the skull crusher load your chest, shoulders, forearms, and core, but only for stability.

Dumbbell Skull Crushers Benefits

The skull crusher, in general, is prized for its ability to target the triceps muscle specifically. If you feel that you lack lockout strength or mass in your triceps, skull crushers are among the best exercises one can incorporate into their arsenal.

Like classical bar skull crushers, the dumbbell skull crusher also lets you train your triceps. However, the dumbbell skull crusher has a few huge benefits over its bar counterpart.

Added comfort

A barbell – whether we are talking about a straight Olympic bar, a triceps bar, or an EZ bar – locks your hands in a fixed position. This can cause discomfort and even pain in your elbows and wrists. If you have limited mobility, you probably can’t comfortably perform bar skull crushers.

Well, dumbbells solve this issue wonderfully. You can grip dumbbells however you want, and you don’t have to weirdly twist your wrists to maintain a good grip on the weight.

Comfort is the primary reason why I prefer dumbbell crushers to barbell skull crushers. I feel that the stress the bar places on my wrists is not safe, especially when lifting heavy. Well, dumbbells let me lift comfortably and safely.

Increased range of motion

If added comfort wasn’t enough, the dumbbell skull crusher has an increased range of motion (ROM). You can lower the weight far lower than with barbells, which potentially increases your gains with dumbbell skull crushers.

Now, you’ll need to pick lighter dumbbells if you choose to go as deep as your flexibility allows. But as a result, the increased ROM should let you hit your triceps harder and see better gains.

Effectiveness at muscle imbalance treatment

Finally, the skull crusher lets you treat imbalance between your triceps muscles.

With a bar, if the triceps of one of your arms is stronger than the other, the stronger muscle will likely do much of the work. Not only will your weaker triceps not work, but the imbalance may become even more pronounced as the stronger triceps continues to eat away load.

And worst of all, if you have muscle imbalance, you may not even feel it with a barbell!

Dumbbell skull crushers, on the other hand, allow you to identify and treat any imbalance. If you see that one of your arms gets fatigued faster than the other, you will know that you have an issue. And then, you will be able to adjust your weight and reps accordingly to ensure that your triceps are getting worked evenly.

How To Do The Dumbbell Skull Crusher?

The dumbbell skull crusher is relatively easy to do. If you don’t pick excessive weight, you should not have any issues with mastering this exercise.

And here’s how to perform skull crushers step-by-step:

  1. Pick up the dumbbells with a neutral grip and lie down on a bench. If the weight is heavy, ask a training buddy to help you get into position.
  2. Press the dumbbells up onto fully extended but not locked arms.
  3. Making sure that your upper arms stay perpendicular to the ground (at 90 degrees), lower the dumbbells to the sides of your head. Inhale as you bring the dumbbells down. Keep your elbows tucked and in line with your wrists.
  4. Go as low as you want – typically, lifters lower the weight until they feel a stretch in the back of the arm.
  5. Lift the dumbbells back up and exhale as you do so.

And here are a few videos to help you better visualise the movement.

Proper Form To Perform A Dumbbell Skull Crusher

A simple exercise such as skull crusher is easy to do wrong. Below are the four most common mistakes I see newbies do in skull crusher (both with dumbbells and a barbell).

Upper arm moving

Ideally, your upper arms should not be moving and should stay perpendicular to the ground at all times. If you don’t maintain the position of your arms, you will be engaging not only your triceps but also the chest and shoulders

This defeats the purpose of skull crusher, so make sure to keep your upper arms motionless throughout the exercise. A bit of movement is fine, but it should not be excessive.

Elbows flaring out

Your elbows should stay in line with your wrists throughout the entire range of motion. If you let your elbows flare out, the load will leak into your chest and shoulders, which you again do not want.

Rushing the movement

The third most common mistake is rushing the movement, especially on the way down. You should lower the weight in a controlled manner – don’t drop it and don’t allow it to come down on you.

If you can’t control the weight, then you should switch to lighter dumbbells.

No tightness in the body

Finally, you should maintain tightness throughout your core and legs so that you can better control the weight and ensure that you are indeed working your triceps. If you twist and move around, you will be engaging other muscles and won’t be able to do skull crushers with textbook form.

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What Are The Dumbbell Skull Crusher Variations And Alternatives?

If you find that dumbbell skull crushers don’t quite work for you, or if you want to add some variety to your training, here are a few alternatives and variations of this exercise.

One-arm dumbbell skull crusher

One-arm dumbbell skull crushers are great if you struggle to maintain that 90-degree angle in the upper arms.

You do one-arm skull crushers the same way as with two arms, but you hold your working elbow with the free hand to help yourself maintain the position of the elbow and the upper arm.

Decline bench dumbbell skull crusher

Skull crushers are typically done on a flat bench, but what if you did the exercise with a decline? Well, you would actually put more stress on the lateral head of the triceps – the head that is on the outside of the back of your arm.

A slight decline is enough for skull crushers – don’t go too low.

If you don’t think that your triceps lateral head needs extra attention, then you should probably stick to regular skull crushers. But if you want to add width and mass to the muscle, decline bench skull crushers could do wonders for you!

Incline bench dumbbell skull crusher

Incline skull crushers target the long head of the triceps, which is on the inside of the back of your arm. The long head is the largest of the three triceps heads, so you should hit it extra hard if you want to increase the size of the muscle considerably.

Again, don’t make the bench’s incline too dramatic, though you could play around to see which angle works the best for you.

45-degree dumbbell skull crusher

In this variation of skull crushers, you angle your upper arms back toward your head, forming an about 45-degree angle with the ground

This variation allows you to emphasise the long head and can be done with either a bar or dumbbells. If you are using a bar, then you’ll notice that you can lower the weight beyond your forehead because of the changed angle.

What’s also interesting about 45-degree skull crushers is that there is no resting point at the top. With that, this variation is more challenging, but it’s great if you want to get your triceps pumped. Definitely do give 45-degree skull crushers a shot!

EZ bar skull crusher

EZ bar skull crushers are ideal if you want to lift considerable weights. Dumbbells are convenient, but you can get only so heavy with them (unless you have access to super-heavy dumbbells).

An EZ bar is way more comfortable on your wrists than a straight bar while delivering the same benefits. You could use a straight bar to do skull crushers, but I don’t recommend that since the straight bar will twist your wrists like there’s no tomorrow.

Proper form with EZ bar skull crushers is the same as with dumbbell skull crushers. But you will need to find a grip width that is comfortable on your wrists and allows you to keep your elbows and wrists in line through the entire range of motion.

Cable skull crusher

With cable skull crusher, you use a cable machine instead of a bar or dumbbells as a load. Lie with your head toward the cable machine, grab the lower handle, and start performing the exercise in the same form as the dumbbell or bar variation.

An interesting trait of cable skull crushers is that the load comes from behind your head rather than from beneath your body. That’s because of the line. With dumbbells or a barbell, the load is always downward due to gravity.

What this means is that cable skull crushers don’t let you rest at the top, and they also put a more or less constant load on your triceps throughout their range of motion.

The Conclusion

I love dumbbell skull crushers, and I think that they are great for both beginners and experienced athletes. But it’s crucial to maintain proper form when performing this exercise. Remember – your elbows and wrists should always be in line, and your upper arms should maintain their position to ensure that you are working your triceps.

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.