Written by Garett Reid | NSCA, CSCS, CISSN, M.S.E.S.S
Fact checked by Kirsten Yovino, CPT Brookbush Institute
FACT CHECKED
As far as cool exercise names go, the skull crusher has one of the best. It certainly sounds more intimidating than the squat, for instance. And while we love exercises that sound awesome, we also need them to yield big muscle gains. The good news is that the skull crusher lives up to its name, and when done correctly, will help sculpt the horseshoe-shaped triceps we're all striving for.
Whether you're a powerlifter looking to improve your triceps extension and lockout or a bodybuilder wanting an awesome triceps exercise to stimulate maximal muscle growth, this article has all you need to know, including:
- Explanation of the triceps muscle group
- How to properly perform skull crushers
- Tips and common mistakes
- Variations and alternatives to skull crushers
- Proper programing for the skull crusher
Overview Of Skull Crushers
The skull crusher is sometimes referred to as lying triceps extensions, which accurately describes the movement. However, the term "skull crushers" is given as the movement consists of a barbell lowered to the head while you lie on a bench. In other words, you'd crush your skull if you dropped the load. Yikes.
Because the arms and shoulder position are out in front of the body, they require less mobility in the shoulder joints and generally allow more weight to be pressed. These two variables make it a favorite in the strength training world.
Generally performed with a straight barbell or EZ-Curl bar, other variations, such as dumbbell skull crushers, can also be useful. We’ll discuss this below.
Skull Crushers Muscles Worked
The triceps are the major muscle group worked during the skull crusher, but we'd be remiss to not mention the upper arms as well, primarily the shoulder stabilizers. These stabilizer muscles keep the arm steady and maintain tension and form. Given the muscles worked, skull crushers could (and should!) be incorporated into an arm workout.
Triceps:
Skull crushers isolate and work the triceps muscles in their entirety. This is pretty obvious given the name. As the "tri" in triceps implies, the muscle is made up of 3 different muscle heads. While all are involved with elbow extension, the primary function of the triceps, each head plays a slightly different role.
Long Head:
The long head of the triceps is unique in that it crosses two joints, the shoulder and elbow, making the triceps a biarticular muscle. As a result, long head exercises typically involve elbow extension in addition to shoulder extension. In this role, it'll help to stabilize the shoulder joint during isometric and dynamic movements. This is why you feel it in your triceps when you perform a straight arm front pulldown or perform movements like freestyle swimming.
The long head sits on the inner portion of the arm and runs down the entire length.
Lateral Head:
The lateral head sits on the outside of the arm and runs along most of the arm, only crossing the elbow joint. While the long head is longer, the lateral head is substantially meatier than the others and is responsible for generating a high amount of force, particularly during lateral head triceps exercises.
Medial Head:
The medial head is the smallest of the three heads and sits in the middle of the posterior side of the arm. Further, it lays underneath the lateral and long head, so you don't see it as much.
The medial head and medial head exercises are responsible for smaller muscle actions with small amounts of force.
Benefits Of Using Skull Crushers
Skull crushers' name is well deserved as it provides major benefits when included in your workout routine. Here are a few reasons you want these in your workout split.
1. Allows a Heavy Load For Stronger Triceps.
Triceps exercises like kickbacks are great for adding finesse to your workout, but they simply don't allow for heavy loads. If you look at the biomechanics, you notice that the load is far from the elbow and shoulder joints during tricep kickbacks.
However, the skull crusher places the load directly above the joints. And the positioning of the arms places the muscle in a more eccentric position, meaning the muscle is long and able to produce more force.
All of this leads to skull crushers enabling a lot more weight to be used, meaning greater muscle building and some seriously strong triceps.
2. Can Be Performed At Home.
While you're supposed to perform skull crushers on a flat bench, you can easily perform these laying on the ground. Another option is to opt out of the barbell and use an easily accessible skull crusher variation: the resistance band skull crusher.
3. Builds Bigger Arms.
The upper arm consists of two muscles: triceps brachii and biceps brachii.
These are the only two muscles you have to work with when building a set of impressive arms. Out of them, the triceps, make up approximately 2/3 of the upper arm's total muscle mass.
There's absolutely nothing wrong with training the biceps. However, many guys exclusively focus on them when building bigger arms. In reality, the muscles worked should be the triceps. So don't forget your dumbbell triceps exercises!
4. Generates Massive Amounts Of Pushing Force.
The triceps is one of three pushing muscles. The other two are the chest (pectorals) and medial and anterior shoulders.
The primary job of the triceps is elbow extension, and negating to train this movement will ultimately leave you with weak pushing power. We love resistance band triceps exercises for improving pushing force.
5. Strengthens Your Lockout On Pressing Exercises.
When we think of pushing force, we generally think of the chest and shoulder muscles pushing barbells in the overhead press and bench press. That's not wrong, but if you look at when most people fail during these exercises, it's usually at about that halfway mark when the elbow begins to break 90-degrees.
This happens to be the point at which the triceps are taking over to complete pressing exercises. In other words, weak triceps caused the lift to fail. This is why using a triceps exercise that allows heavy weight is essential for all weight lifters.
How To Properly Perform Barbell Skull Crushers
Even though barbell skull crushers are an isolation exercise, the movement can be tricky. As we want you to get the most out of this exercise, here are step-by-step instructions for performing barbell skull crushers properly. Don't forget to move slowly and concentrate on that mind-muscle connection throughout the barbell movement.
Set-Up For The Barbell Skull Crusher:
To set up, you need a flat bench and a barbell. Keep in mind a barbell does not need to be an Olympic-size barbell. You can use one, but shorter barbells or even an EZ-bar work fine. As you are able to use an angled grip with an EZ bar, we actually prefer this as it takes the stress off the elbow joint.
Starting Position For The Barbell Skull Crusher:
Sit on the bench and hold the barbell overhand with a shoulder-width grip. Lay back on the bench with your entire body on and feet planted on the ground.
Lift the barbell, so it's directly above your upper body with elbows fully extended.
Movement Pattern For The Barbell Skull Crushers:
Keeping your elbows stationary, flex your elbows to allow the load to come down to your head. This should be done in a slow and controlled manner for obvious reasons.
Once the barbell comes down to your head, you will extend your elbow powerfully and lift the load until your elbow is fully extended.
Again, the elbows remain still the entire movement as this is an isolation exercise.
Common Mistakes Performing Barbell Skull Crushers
While skull crushers are one of the more complicated isolation exercises, there luckily aren't too many steps. That said, a few mistakes happen more often than others. Watch out for these when training.
1. Letting The Elbows Flare:
Inexperienced lifters are more to prone to letting the elbows flare out. If this occurs too much, you will mitigate the involvement of the triceps. Keep them solid and close to your body.
2. Using Too Much Weight:
For whatever reason, lifters tend to let their egos get the best of them. While we have said numerous times one of the advantages is that skull crushers allow for heavy weight, this is relative.
Not only can the form be a bit complicated, but a lot of stress can also be placed on the wrist (again, this is why we like the EZ-bar). Therefore, keep your ego in check and focus on solid form, emphasizing wrist, elbow, and shoulder stability, especially as a beginner. The weight will come. As long as you're using correct form and progressively overloading, you'll make gains.
3. The Arm Angle Changes:
We want your elbow pointing straight up the entire movement. Most people can keep accomplishing this the first couple of reps. However, after a few more, the arm positioning begins to change, usually drifting backward.
4. Allowing Too Much Elbow Movement:
Similar to the above two, in order to get optimal activation out of the triceps, you need to keep the elbow as still as possible. In addition to flaring, the elbow can come inwards, toward your feet, or back at your head. Any of these movements can put undue stress on the elbow joint, potentially leading to elbow injury.
This requires significant activation from your shoulder stabilizer muscles, so go lighter at first. Once these muscles are trained, you can then focus on adding weight.
Proper Programming
The skull crusher can work on various training days, depending on how you program it. Options for where to incorporate the move include an upper body workout, push day workout, or an arm day.
The skull crusher is a powerful isolation exercise that can be used with both heavy and light weight. Here are some basic parameters to follow.
Using The Barbell Skull Crusher For Strength:
Skull crushers are one of the few exercises that we like to go heavier on (relative and absolute). In fact, it's one of a handful of triceps exercises we recommend using for improving strength. That said, you still shouldn't max out.
The heaviest you should go should be around the 6 rep range with 3-4 sets.
Using The Barbell Skull Crusher For Muscle Hypertrophy:
The primary driver for muscle hypertrophy is accumulating volume, assuming the load is heavy enough. To do this, using a lighter weight that allows 3 sets of 8-12 reps is optimal.
While using a high-rep burnout set once in a while (15-20+ reps) is a fun tactic, this should be done sparingly. As the skull crusher does allow you to use heavier weight, save the ultra-low weight for other exercises.
Skull Crusher Variations
Skull crushers are easily one of the best triceps exercises you can do. But having other exercises in your tool belt is always a good idea. You may find yourself in a gym that lacks the same equipment. Or perhaps your training has become stale, and you just want a little extra variety.
Regardless of why you may want a variation, these options will deliver.
1. Dumbbell Skull Crusher:
The movement pattern of a dumbbell skull crusher is exactly the same as performing a barbell skull crusher. This includes the initial set-up, starting position, and entire movement.
The only difference is you will use a pair of dumbbells. Also, use a neutral grip instead of an overhand one when performing dumbbell skull crushers. As you come down, the dumbbells will track, so they're on either side of your head. You then power up exactly the same.
Dumbbells can be extremely useful for someone with any type of mobility issue in their elbow and shoulder joint. And if you're unsure where you stand with mobility, we suggest testing your mobility right away.
Because the dumbbell is held in only one hand, you are able to alter your position to train around the pain. Don't forget some tricep stretches after your workout!
2. Rolling Dumbbell Triceps Extensions:
Rolling dumbbell triceps extensions are like skull crushers on steroids. Apart from using dumbbells, these lying triceps extensions will appear close to the same exercise, with the primary difference occurring at the positioning of the elbow joints.
First, you need to pick up a pair of dumbbells. From here, the initial set-up is exactly the same as skull crushers, including the starting position with arms extended straight up. The only difference is you will be holding the dumbbells with a neutral grip.
Now you're ready for the movement pattern. You will begin by allowing the dumbbells to drop back toward your head, just like barbell skull crushers. Ideally, you get the dumbbells to sit on either side of your head with the elbows remaining in the same position.
Instead of performing elbow extension as you do with skull crushers, you will first allow the elbow joints to drop straight back until they're almost in line with the head. From here, you will power your elbows back forward to the original starting position and then extend your elbows.
This provides better muscle activation by enabling more stretch in the muscle fibers of the triceps, requiring greater involvement from the long head due to shoulder extension, and allowing the muscles to move heavier loads due to body movement.
3. Incline Skull Crushers:
Incline skull crushers simply involve using an incline bench rather than a flat bench, and your arms won't be perpendicular to your body. While you'll still have them extended in the air, they will be at an incline angle when comparing them to your torso, similar to an incline bench press.
The primary benefit that some people report is the mitigation of elbow pain. This move would work well in a chest and triceps workout.
4. Resistance Band Skull Crushers:
This version is great as a rehab move, or for beginners or anyone looking to throw in a good burnout set in their workout routine. Again, the basic movement pattern is exactly the same, except you perform the skull crusher with a resistance band.
Depending on the length and thickness of your band, you will wrap them under your flat bench. There are a few ways to do this:
- Place the entire body under the bench near your head.
- For shorter or thicker bands, only place one strap under the bench.
- For longer or skinny bands, place the strap under the leg and come up behind the end near your head.
It doesn't matter how you set it up as long as it works. Using an overhand grip works best.
Skull Crusher Alternatives
Now perhaps for whatever reason, you can't perform barbell skull crushers. Or, maybe you just want some other exercises to use in your triceps workouts. Here are some awesome skull crusher alternatives.
1. Close Grip Bench Press:
The close grip bench press is an amazing exercise that allows you to place a heavy load on the triceps while using deep elbow flexion. Similar to the barbell bench press, with this barbell triceps exercise, you'll bring your hands in instead of using a shoulder-width grip so they're slightly narrower than shoulder width.
Then bring the barbell down below your nipple, a bit lower than the traditional bench press. As you come down, be sure to keep your elbows tucked. People tend to let their elbows flare, which puts unneeded stress on the joints.
You'll notice your elbows come lower than normal, providing that deep elbow flexion. Close grip bench presses are a classic barbell triceps extension movement used by strength athletes to build impressive pushing strength.
2. French Press:
The French press looks similar to a skull crusher but is done sitting on a bench with the arms extended straight up. Due to this position, the long head is stretched considerably, giving it a little extra attention.
If you like overhead extensions, the French press is a good option.
3. Triceps Dip:
We love dips. They're an amazing exercise to increase your overall pushing power and athleticism. Further, you can slightly alter your movement pattern to change up muscle activation. To hit the triceps more, you want to keep your torso upright to decrease activation of the chest.
4. Close Grip Push Up:
The close grip push-up follows the same logic as the close grip bench press. Using narrower hand placement greatly increases the activation of the muscle in the triceps. Plus, these tricep exercises are perfect to use at home!
5. Cable Machine Overhead Triceps Extension:
Our last favorite triceps extension is done using the cable pulley and rope attachment to perform an overhead extension. Aren't cable arm exercises just the best?
Skull Crushers: Get Ready to Feel Your Triceps Burn!
Skull crushers are a hell of a triceps exercise and can improve anyone's workout program. They build strong triceps for strength athletes and big triceps for bodybuilders (have you seen the tris on Chris Bumstead?!). It may take a bit of time to get used to the movement, but when you do, your triceps will grow and your major pressing lifts will improve. Hello, triceps muscle hypertrophy!
Related:
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15 Best Bodyweight Triceps Exercises
- Triceps Pushdown Exercise
- 8 Kettlebell Exercises to Build Horseshoe Triceps
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Garett Reid
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