HomeExercise LibraryHow To: Dumbbell Skull Crusher

How To: Dumbbell Skull Crusher

Dumbbell Skull Crusher
The skull crusher is the ultimate isolation exercise for the triceps, if I had to pick 2 exercises to perform for my triceps without a doubt the skull crusher would be one of them!
Ensure your form is strict (elbows in, only moving your forearm) and proceed to overload the muscle, continually increasing the weight when possible and you'll see your triceps start to blow up in size and strength!

I recommend trying both the dumbbell, barbell and unilateral versions of the skull crusher.

Movement: Isolation

Targets: Triceps

Required: Dumbbells & Flat Bench

Optional: N/A

Dumbbell Skull Crusher Form

Grip a dumbbell in each hand, lay down on a flat bench and fully extend your arms.

Without moving your upper arms proceed to lower the dumbbells by moving your forearms downward toward your head.

Pause for 1 second as the dumbbells are almost touching your forehead.

Extend your elbows to drive the dumbbells back up until your arms are fully extended, hold this contraction for 1 second.

Repeat for the desired number of repetitions.

Dumbbell Skull Crusher Variations

Behind The Head Extension

A skull crusher lowered to behind the head, increasing the range of motion and tension on the triceps as opposed to stopping directly above the forehead.
Ensure elbow position is not compromised as you'll likely have to drop the weight in order to complete the additional range of motion.

See also
How To: Close Grip Lat Pulldown

Barbell Skull Crusher

A skull crusher performed with a barbell.
As with the dumbbells, elbows must remain tucked in and only the forearm should move.
The barbell skull crusher can be performed fairly heavy, and is a great exercise for overloading the triceps.

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Bowflex SelectTech Adjustable Weights

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Common Dumbbell Skull Crusher Mistakes

Utilizing A Partial Range Of Motion

There's no reason to work in a small range of motion on your overhead extensions, opt to lower the bar ALL the way down in front of your head before driving through the triceps until they're locked out at the top of the movement.
Partial range of motion = partial triceps activation.

Flaring Your Elbows Out

When performing any triceps exercise, whether it be a dumbbell overhead triceps extension or a rope pushdown it’s imperative you keep your elbows tucked in by your sides.
Flaring your elbows outwards is often a sign that the weight is too heavy (as you’re trying to muscle the shoulders in to assist with moving the weight).
Flaring the elbows on triceps exercise places your shoulders at a high risk of injury not to mention you’re only going to applying a small amount of tension to the triceps as the shoulders are trying to take over and lift the weight.

See also
How To: Dumbbell Rear Delt Fly

If you find yourself constantly flaring your elbows lower the weight and consciously practise tucking your elbows in to your side on each repetition until it becomes natural.

Lifting Too Light

If you don’t generally train in the lower rep range I recommend you give it a try, stop lifting in the 10 – 15 rep range for at least a month and focus on heavy, low rep sets. Once you start to see results you won’t want to go back.

Now, you may still think high reps are beneficial, but let me tell you they’re far from it.

High repetitions result in increased stress on your CNS, increase in localized inflammation and increased soreness.

“Movements or exercises that do not give the muscle the required resistance, but are the kind that involve a great number of repetitions, never break down any tissue, to speak of. These movements involve a forcing process that cause the blood to swell up the muscle, and simply pump them up”– George F. Jowett, 1926

Similar & Substitute Exercises 

  • Barbell Skull Crusher
  • Triceps Dips
  • Overhead Triceps Extension
  • Triceps Push down

Any Questions Regarding The Dumbbell Skull Crusher? Ask Below!

Scott J.
Scott J.
I’m SJ. I’m a fitness enthusiast and published author. I transformed my body from a skinny fat 135lbs with 18% body fat to a solid 192lbs at 8% body fat. I became qualified in a field I was passionate about. I founded several online businesses that allow me to pursue ideas and projects in my life that I am passionate about without having to constantly worry about money. I published several eBooks explaining the training and dieting techniques I used to achieve the body I have today. I learnt a plethora of new information on dieting and fitness by reading and applying what I read, to find out what does work and what doesn’t work, because as I’m sure you’ve noticed the health and fitness industry is full of non-sense claims and BS. I found out what was true and what worked for me and applied that knowledge. And you bet I had fun during the whole process.

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