Your triceps make up about two-thirds of your upper arms, so if you want bigger arms, building your triceps is a must.

When it comes to developing the tris, every weightlifter has a different approach. Two of the most common triceps lifts you’ll hear about are skull crushers and lying triceps extensions. Some of your gym buddies might even tell you these two lifts are identical.

Are they right? In this blog, we’ll discuss the triceps muscles, the similarities and differences between lying triceps extensions and skull crushers, how to do each exercise, and the advantages of adding these lifts to your repertoire at AFAC’s gym in Thornton, Colorado.

What Are the Triceps?

The triceps brachii – or “triceps” for short – is a large, three-headed muscle in the upper arm. The three heads of the triceps are the long head, medial head, and lateral head.

The triceps are located on the back of the upper arm. Triceps run from the shoulder to the elbow along the humerus, which is the main bone of the upper arm.

When you contract your triceps, your elbow straightens and your forearm extends. If you relax your triceps and flex your biceps, your elbow will bend and your forearm will retract.

The triceps also stabilizes the shoulder joint at the top of the humerus. Since the shoulder has the greatest range of motion of any joint in the body, it tends to be unstable, and the triceps plays a major role in supporting it.

To strengthen and build your triceps, you need equipment like dumbbells or a barbell that you can use to extend your elbow joint under resistance.

What’s the Difference Between Lying Triceps Extensions and Skull Crushers at the Gym?

The lying triceps extension and skull crusher are both exercises that isolate the triceps and involve extending the elbows (straightening the arms). This movement is done under the resistance of holding a weight such as a dumbbell or barbell.

The main difference between a lying triceps extension and a skull crusher is that a skull crusher is a type of triceps extension.

A triceps extension can be done from a lying down, seated, or standing position. When you do a triceps extension, you hold a weight above your head, bend at the elbows to lower the weight behind your head, and then lift the weight back to the starting position.
The skull crusher is almost always completed from a lying down position. When you do a skull crusher, you lower the weight to behind your head or to your chin, face, or forehead.

They’re Basically the Same Exercise

So, to summarize, the only difference between skull crushers and lying triceps extensions is that when you perform a skull crusher, you can lower the bar to your forehead, nose, chin, or behind your head. That means skull crushers are customizable to a certain degree.

A lying triceps extension, on the other hand, is almost always performed by lowering the weight behind your head.

What Are the Advantages and Disadvantages of Lying Triceps Extensions and Skull Crushers at the Gym?

Even though a skull crusher is considered a variation of a lying triceps extension, both exercises have pros and cons for increasing the strength and size of your triceps.

Advantages of Lying Triceps Extensions

They build arm strength — Lying triceps extensions with a barbell are good for progressively overloading your muscles. You can increase the weight on the barbell in small increments, which allows you to gradually boost triceps strength and mass.
They activate the long head of the triceps — The long head of the triceps has two main functions, extending the elbow and extending the shoulder. The overhead lying triceps extension makes you extend your elbows and shoulders to keep the weight steady above your head. This targets the long head of the triceps.
They improve your performance in other lifts — While you isolate your triceps with triceps extensions, you’ll build strength to improve other lifts like your bench press and overhead press.
They give you a deeper stretch and tension compared to skull crushers — By lowering the weight behind your head during lying triceps extensions, you’ll achieve a deeper stretch in the long head of the triceps. You’ll also increase the time your triceps are under tension compared to skull crushers.

Disadvantages of Lying Triceps Extensions

Using a straight barbell might cause wrist pain — Using a straight barbell during lying triceps extensions forces your hands into a fully pronated (palms facing away from your body) position. As you lower the barbell behind your head, you might feel strain on your wrists.
They might cause elbow pain — If you feel elbow pain after doing lying triceps extensions, it could be a sign that you’re allowing the weight to drop down behind your head instead of lowering it with control. If you’re not able to slowly lower the weight during a triceps extension, you might need to reduce the weight.
They can create muscle imbalances — Lying triceps extensions with a barbell are a bilateral exercise, which means you’re working both arms at the same time to move the weight. When you do this, there’s a chance your dominant arm or other arm muscles will help you lift the weight, which could take the focus off your triceps.
They put more strain on your rotator cuffs compared to skull crushers — Lying triceps extensions put your shoulders into a higher degree of flexion than skull crushers. This puts your rotator cuffs under more strain.

Advantages of Skull Crushers

They target the medial head of the triceps — Compared to other triceps exercises, skull crushers are effective at targeting the medial head of the triceps. While it’s less visible than the long and lateral heads, the medial head of the triceps is important to the stability and strength of the upper body.
They can be modified to allow for more variations — Skull crushers can be easily modified to meet your fitness goals, preferred equipment, and personal biomechanics. You can use barbells, dumbbells, kettlebells, or resistance bands with skull crushers.
They give you a clear beginning and end position — Unlike lying triceps extensions which allow you to extend the weight behind your head as far as you can go, skull crushers have a clear place to stop moving your weight — right in front of your skull. This consistency can intensify your workout and prevent overextension.
They can be used to address muscle imbalances — You can do skull crushers with dumbbells, which means you can isolate each arm unilaterally and target weaker muscles. This can help balance the strength and size of your right and left arms.

Disadvantages of Skull Crushers

They are riskier when you use heavier weights — When you do skull crushers, you’re lowering a weight close to your face. Remember that you don’t have to bring the bar down to your face just because the exercise name has the word “skull” in it. Make sure to always grip the bar firmly with your thumbs around the bar. Beginners to this exercise should use lighter weights to avoid injury. As you start to lift heavier, the risk of dropping the weight onto your face or head increases. If you’re unsure whether you can handle the weight you’re using, get a spotter to assist you. Regardless of your experience level, avoid lifting excessively heavy weights with the skull crusher.
They require more control — During skull crushers, you need to have full control during the eccentric (lowering) and concentric (lifting) phases of the exercise. Whenever you lower a weight toward you, it’s temping to let gravity take over and create momentum. This can strain your joints and make the lift less effective in building your muscles.
They can cause elbow pain — Some lifters say that skull crushers give them elbow pain. You can try reducing the weight and adjusting your grip to address this, but if you notice severe elbow pain or sustain an injury during skull crushers, this might not be a good exercise for you.

How to Do Lying Triceps Extensions at the Gym

Lie down on a flat bench with a neutral spine. Plant your feet firmly on the floor for stability and support.
Hold your barbell directly above your upper chest with straight arms and an overhand (pronated) grip.
Your hands should be shoulder-width apart. Tuck your elbows close to your body.
Bend at the elbows so that only your forearms move. Lower your barbell over your head until it reaches just behind your head.
To give yourself a big stretch on the triceps, flex your shoulders back to lower the bar further behind your head until it reaches below your shoulders. Keep your elbows at a 90-degree angle.
Hold this position for a moment.
Extend your shoulders first to begin lifting the barbell up to the top of your head.
Then, extend your elbows to push through your triceps and straighten your arms vertically above your upper chest.
Your elbows should not be locked or hyperextended.
Repeat for the desired number of reps and then set the barbell down safely.

How to Do Skull Crushers at the Gym

Lie down on a flat bench with a neutral spine and with your feet planted firmly on the floor.
Hold a barbell directly above your chest with a shoulder-width, overhand (pronated) grip.
Keep your wrists straight and stacked with your elbows and shoulders. Do not bend your wrists back.
Bend at the elbows to bring the weight slowly toward your forehead until it almost touches your forehead.
Hold that position for a second.
Contract your triceps to straighten your arms and lift the weight to its starting position.
Repeat for the desired number of reps and then set the barbell down safely.

Training Your Triceps at AFAC Gym

Lying triceps extensions and skull crushers are similar exercises, and both of them are effective at targeting your triceps brachii. Are you wondering which one is better? The best triceps exercise for you is the one that feels most comfortable and gives you the strongest engagement of your triceps. As long as you use proper form, either exercise will help you isolate and build your triceps.

When you work your triceps at AFAC gym, you have lots of choices for the equipment you use. Lying triceps extensions and skull crushers can be performed with standard barbells, EZ bars, dumbbells, kettlebells, cable machines, and resistance bands, and AFAC gym has an ample supply of all these options.

AFAC gym is available to support you in your strength training goals. Our team of personal trainers can help you learn good form when doing lying triceps extensions, skull crushers, and any other workouts you’d like to try at our gym. We can also tailor a strength training and cardio program to help you reach your goals and get the results you’re striving for.

If you’d like more information about our strength training equipment, cardiovascular machines, and packed schedule of fitness classes, please stop by and speak to our team at AFAC gym. We’ll give you a tour and show you why we’re the best gym in Thornton, Colorado. For more information and assistance, you can also contact our gym owner, Susan, at 720-849-0245 or susan@adventurefitness.club.