How to Perfect the Skull Crusher Workout

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Does the skull crusher workout sound a little ominous to you? It gets its name because you’re lying on your back and lowering the weight toward your forehead. If you don’t like the name, call it a lying triceps extension.

The skull crusher is an isolation exercise for the triceps to improve their size and strength. Because the triceps make up over ⅔ of the upper arm, giving them some love and attention will give you more flex appeal and improve your lockout strength. Increasing your lockout strength has a direct carryover to most pressing exercises, including the bench press and overhead press.

Here, this CPT will do a mini deep dive into the skull crusher for your muscle-building and flexing pleasure.

Medical disclaimer: This article is intended for educational and informational purposes only. It is not intended as a substitute for medical advice. For health advice, contact a licensed healthcare provider.

How to Do the Skull Crusher

Start by lying face up on a weight bench with a barbell or EZ-curl bar locked out in the top position, with your hands about shoulder-width apart and your palms facing away from you.
Lower the barbell toward your forehead. Keep your elbows stationary and stacked over your shoulders.
Push the barbell back up, reversing your path until you return the bar to the starting position.
Reset and repeat for the desired number of repetitions.

Common Skull Crusher Mistakes to Avoid

The skull crusher exercise, as great as it is for the triceps muscle group, puts a lot of stress on your wrists and elbows. Avoiding these common mistakes when you do skull crushers is imperative to get the best out of this exercise.

Ego Lifting

The skull crusher is not a technical exercise and is one that is simple to perform for increased size and strength of the triceps. So, there may be a tendency to go too heavy and put unnecessary stress on the wrists and elbows. Best to go with a moderate load and more reps to keep your upper body in a good position.

Elbow and Wrist Position

When your wrist hyperextends and your elbows flare out, you will lose tension in your triceps, which is the whole point of this exercise. Ensure you use a weight you can control, and if that doesn’t work, use one of the variations listed below.

Grip Position

Understandably, everybody is put together differently, with different limb lengths, joint structures, etc. But the best grip for the skull crusher is a shoulder-width overhand grip. You may need to adjust for comfort, but be careful not to go too wide, which may flare your elbows out excessively.

Skull Crusher Benefits

Here are three benefits you can expect when you make skull crushers a part of your workout routine.

More Flex Appeal

The triceps are three muscles that make up ⅔ of your upper arm and are often forgotten because lifters fall in love with the biceps. But focusing on them with skull crushers and other triceps-focused exercises will build muscle for more flex appeal.

Improved Lockout Strength

The triceps’ primary function is elbow extension, which is a factor in almost all pressing exercises, such as the bodyweight push-up, bench press, overhead press, and dumbbell pressing variations. Improving the strength and size of the triceps will have a direct carryover to these exercises because the final second of most pressing exercise relies on triceps strength.

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Stronger Triceps

Strong triceps are a factor in all pressing movements, and strengthening them improves overhead stability. Overhead stability is essential to stabilizing the barbell after finishing the overhead press or Olympic lifts. The stronger you become, the more triceps could become your weakest link.

Skull Crusher Variations

Making minor tweaks to your skull crusher (or lying triceps extension, if you prefer) will prevent overuse injuries and training boredom. Here are some variations to take out for a spin for your triceps-building pleasure.

Incline Skull Crusher

Performing skull crushers on an incline bench gives your triceps a slight stretch in the bottom position for an increased ROM and better muscle-building potential with a lighter load. Plus, you’re training the triceps from a different angle to assist with better muscle development.
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Skull Crushers on the Floor

Performing skull crushers on the floor with a barbell or dumbbells provides more stability and form feedback if anything is amiss with your skull crusher technique.

Overhead Triceps Extension

Overhead triceps extension can be performed with bands, cable machines, dumbbells, or an EZ bar. All these variations put your triceps in a deeper stretch to help stimulate more muscle-building and strength gains. Triceps hypertrophy is more significant¹ when elbow extension training is performed in the overhead position because the long head of the triceps is focused on more.

Dumbbell Skull Crusher

Dumbbell skull crushers perform similarly to the barbell variation but have two crucial differences. First, the dumbbells can be held with a neutral grip, which is easier on the elbow joint. Second, this variation can be performed unilaterally to strengthen muscle imbalances between sides.

RELATED: Best Dumbbells

Skull Crusher Workout: Final Thoughts

The Skull Crusher is a triceps exercise with an ominous-sounding name, but it is an excellent isolation exercise for the three muscles of the back of your arm. Adding size and strength to the triceps will give you:

More flex appeal
Better lockout strength for pressing exercises
Improved shoulder stability in the overhead position

Add the skull crusher or one of the variations above to your workout once or twice weekly.

Skull Crusher Workout: Q&A

Is skull crusher a good exercise?

Skull crusher is a fantastic exercise to build strength and muscle in your triceps, and one the best triceps exercises out there. Skull crushers and their variations isolate the triceps and put in through an extensive ROM for better muscle-building potential.

How to do a skull crusher properly?

To get the best out of the skull crusher triceps workout and ensure proper form, your torso must be stable on a flat bench, grip shoulder-width apart, wrists neutral, and your elbows tucked in the entire time.

How much should I be able to lift with skull crushers?

Load is dictated by form. Use a weight that allows you to complete your repetition range with good form while feeling the burn in your triceps. When bodybuilding is your goal, 2-4 sets of 8-15 reps is a great start. If you’re a beginner, 3 sets of 8-12 reps with a load that allows you to focus on form is a good start.

Is skull crusher workout push or pull?

The triceps are a pressing muscle whose primary function is elbow extension. So any skull crusher workout you perform is a push exercise, not a pull exercise. Exercises like pull-ups or deadlifts are classified as pull exercises.

References

Maeo S, et al. Triceps brachii hypertrophy is substantially greater after elbow extension training performed in the overhead versus neutral arm position. Eur J Sport Sci. 2022 Aug 11:1-11. Doii 10.1080/17461391.2022.2100279. Epub ahead of print. PMID: 35819335

Shane McLean, CPT

Shane McLean is a certified personal trainer who’s worked with a wide variety of clients, from the general population all the way to ex-Navy Seals and college athletes. When he isn't training in his garage gym, he's drinking copious amounts of coffee while spreading the good word about health and fitness.