How to Do Skull Crushers Properly for Mass and Strength

Here are the ins and outs of this tried-and-true triceps exercise.

Your triceps make up two-thirds of your upper arm, and are involved in overhead presses, bench pressing, and other pushing exercises. If you want to build an impressive pair of arms while improving your upper-body strength, then you cannot neglect your tris

The skull crusher is one of the best exercises for improving your triceps. Anyone from seasoned powerlifters, who want to improve their bench, to bodybuilders looking for more size, to general gym-goers who want a solid pump — it’s a triceps exercise for the people! Below, we dig deep into the skull crusher to give form tips, outline benefits and provide alternatives and variations to best suit your training needs. 

Skull Crusher Video Guide

Our skull crusher video below dives even deeper into this mass-building accessory movement. Check it out below. 

How to Do the Skull Crusher

Below is a step-by-step guide on how to properly set up and perform the skull crusher using a barbell.

Step 1 — Align Your Wrists and Shoulders

Skull Crusher align wrists

Start by lying down, back first, on a sturdy workout bench. The barbell should be locked out at the top position, with your hands set about shoulder-width apart. The width of your grip can vary based on flexibility and comfortability. The key is that the lifter should feel that they can flex the upper back muscles and squeeze their shoulder blades together. This will be essential for the next steps.

Step 2 — Lower the Barbell

Skull Crusher lower bar

Now, begin to lower the barbell towards the forehead (hence the name, skull crusher). It’s important to keep the elbows actively tucked in. If the elbows flare out a little, that’s ok and even natural, but too much flare will deactivate the triceps. 

Form Tip: Squeeze the barbell — hard. When you actively grip the bar, your other muscles will engage, making it easier to maintain good form throughout the exercise.

Step 3 — Stretch Your Triceps

Skull Crusher stretch

Once the bar is at your forehead, lower your shoulders and roll your arms back so the bar is behind your head. At this point, you should feel the entire back of your arm engage and stretch intensely. 

Form Tip: Don’t haphazardly let the bar drop behind your head. Control it. Slowly lower it past your forehead and behind you until you feel that stretch. 

Step 4 — Stay Tight and Lift

Skull Crusher lock out

After you’ve held the bottom position of the lift for a beat, drive the bar back up, reversing the path you took to lower the bar. You should keep your elbows tucked throughout the lifting (or concentric) phase. 

Form Tip: Aim to follow the same path you took to lower the bar. This will ensure a smoother lift and help prevent you from jerking the bar out of alignment, causing elbow and/or shoulder pain. 

Benefits of Skull Crushers

Below are four benefits of the skull crusher that lifters can expect when implementing it into their training regimen.

Stronger Triceps

Strong triceps are key for all pressing movements and overhead stability. Powerlifters must have strong triceps to assist in locking out of the bench press. Weightlifters must perform triceps work as they are necessary for elbow extension in the receiving phases of the snatch and jerk. And strongmen who hoist logs that weigh over 300 pounds overhead need triceps strength to finish the lift. The stronger you get, the more you lift, and the more you lift, the more your triceps become a factor. 

Improved Lockout Strength

The triceps are responsible for elbow extension, which is a key factor in finishing the end of the range of motion of the bench press, snatchclean & jerk, and overhead press. Most power and strength athletes will see improvements in lockout performance with added triceps strength and hypertrophy work (assuming they are perfecting any technical faults resulting in press outs).

Healthier Elbows

Healthy joints often come from proper training volume, technique, and increasing muscle hypertrophy and force production so that volumes and loading can be absorbed by the muscles themselves rather than on the tendons, ligaments, and joints. Stronger triceps (along with using proper form) is key to increasing pressing performance and minimizing overuse injury to the joints and connective tissues.

Bigger Arms

For some strength and power athletes, bigger, leaner arms are an added goal. The triceps are roughly two-thirds of the arm, so more dedicated tricep work could help you achieve a superior set of pipes.

Muscles Worked

The skull crusher is a single-joint exercise that specially targets the triceps. Unlike other triceps movements, like close-grip bench press and dips, which recruit multiple muscles, the skull crusher primarily hits the triceps. That said, there’s another important — and often overlooked — muscle group that benefits. 

triceps muscle
I T A L O/Shutterstock

Triceps

The triceps are responsible for elbow extension, which is a factor in most pressing movements (bench press, overhead presses, push-ups, dips, overhead stability, etc.). The skull crusher isolates the triceps by having the lifter perform deep elbow flexion while stabilizing the shoulder and wrist joints (see below).

Shoulder Stabilizers

While the shoulder muscles themselves are not as engaged, the scapular stabilizers and rear deltoids are working diligently to stabilize the shoulder socket to allow the lifter to remain in a fixed position. By not allowing shoulder movement, the lifter can force the elbows to flex to acquire necessary ranges of motion, increasing the demands on the triceps to extend the elbow joint fully. Simply put: Your shoulder stability will improve.

Who Should Do Skull Crushers?

Below, we list how specific types of lifts can benefit from the triceps. Note: All general gym-goers can reap these same benefits, but for the sake of specificity, we kept this list more focused.

Strength and Power Athletes

The skull crusher is an accessory movement to increase triceps strength and hypertrophy. This can also help increase injury resistance for the elbow joint and improve overall elbow extension abilities necessary for sports performance.

Olympic Weightlifters

The triceps are responsible for overhead stability and elbow extension in the snatch and the jerk portions of the competitive lifts. By increasing triceps training by implementing single-joint exercises like skull crushers, you can help a lifter build more raw strength and muscle mass necessary to lock out lifts (assuming there is no technical fault).

Bodybuilders

The skull crusher, while not as “functional” as other pressing movements like push-ups and dips, can be a good option for lifters looking to increase triceps training volume without the added wear and tear on the shoulders and chest (such as if they were to do more push-ups, bench press, etc.) They also are vital for proper elbow extension and upper body strength.

Strength Sets, Reps, and Weight Recommendations

Whether you want to get bigger, stronger, or increase your triceps’ work capacity, your sets and reps and rest time will be the determining factor. Here’s how many you need to do based on a different training goal. 

For strength

Lifting heavier weight with longer rest time is the key here. You’ll overload your triceps but also engage your central nervous system, essentially priming your body to lift heavier loads in the future. Do four to six sets of four to eight repetitions, resting two to three minutes between sets. 

For Muscle Mass

Be like Goldilocks here and find a set and rep scheme in the middle of light and heavy. Typically, you want to lift a weight that allows you to do around ten reps. You’ll accumulate more mechanical tension or stress, which is what your muscle needs to breakdown and then bounce back stronger. Do four to six sets of eight to 12 repetitions, and rest one to two minutes between sets. 

For Muscular Endurance

Some lifters may want to train greater muscle endurance (for sport), in which higher repetition ranges and/or shorter rest periods are recommended. To achieve this, simply up the reps you’re doing, but be sure to lighten the weight on the bar. Perform two to three sets of 15 to 20 reps, resting for a minute to a minute and a half between sets.

Skull Crusher Variations

Below are three skull crusher variations that can be used by coaches and athletes to keep training varied and progressive.

Dumbbell Skull Crushers

Dumbbell skull crushers are done similarly to the barbell or EZ-bar variation; however, you can attack the triceps unilaterally by using dumbbells. This can be beneficial for lifters who may have muscle imbalances or coordination issues. Additionally, this may allow for a deeper elbow flexion angle, which may improve muscle development.

Incline Bench Skull Crushers

The incline bench skull crusher variation can be done with any loading (barbell, dumbbell, kettlebell, etc.) and is set up with the bench at a slight incline. By adding the incline, you can slightly increase the stretch on the triceps and hit the muscle from slightly different angles.

Negative-rep Skull Crushers

Negatives, also called eccentrics, are highly effective at creating muscle damage and hypertrophy. To do this, an athlete should have a spotter spot them as they slowly lower the supra heavy load down under control. The spotter should keep control and make sure the load doesn’t come crashing down on them. When it is time to lift the load, the spotter can lift the weight to the top position, repeating for reps.

Skull Crusher Alternatives

Below are three skull crusher alternatives coaches and athletes can use to increase triceps strength and size.

woman doing overhead extension
Kavee29/Shutterstock

Close-Grip Bench Press

The close-grip bench press is a bench press variation that targets the triceps and chest by narrowing the grip width on the barbell. In doing so, the lifter must tuck their elbows into their sides. This variation can be easily swapped for regular bench press when athletes have issues locking out bench press reps or limiting shoulder involvement in the press.

Dips

Dips are a great mass building exercise for the triceps, chest, and front shoulders. You can do them with your own bodyweight or strap on a dipping belt to add weight and overload the target muscles even more.

Overhead Triceps Extension

The overhead triceps extension can be done with a dumbbell, a barbell, an EZ-bar, or a cable machine. This exercise targets the similar segments of the triceps that the skull crusher does and may be less painful on joints if a lifter has elbow issues. Note: pain should not be dismissed and properly reviewed by a medical professional.

Frequently Asked Questions

When should I do skull crushers in my workout?

Do skull crushers early in your arms training. The reason being that the skull crusher can be loaded up with more weight, and so you don’t to rob yourself of the potential to lift heavier by pre-fatiguing your muscles with other exercises.

Skull crushers hurt my elbows. What should I do?

Probably not skull crushers. First, if you’re experiencing any pain, you should consult with a doctor. However, a good rule of thumb is: if it hurts (and not in a typical workout way), you should steer clear. Try some cable variations, like pushdowns. These are generally a little easier on the elbow and shoulder joints.

Are skull crushers more effective when done with a barbell?

Not necessarily. The aim of this exercise, like all exercises, is to tax the target muscle as effectively as possible. If you can feel your muscle working, then it is. And if you can’t, then you need to try something else. Which exercise works best is different for everyone. If you don’t feel your tris engage while using a barbell, then try attaching a triceps handle to a cable. Or use a pair of dumbbells. Even kettlebells work. Play with it.

Featured image: Skydive Erick/Shutterstock

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