Tricep dips vs skull crushers: which is best for supersizing your arms?

When it comes to adding size to our arms, most people turn their attention to the biceps. Busting out endless curls may feel great and leave you with an impressive pump, but what you should be thinking about is the triceps. 

The triceps are bigger than your biceps, they’re actually the largest muscle in your arm and make up two-thirds of it. Neglect that amount of muscle and you’re only limiting your chances for super-sized arms. Not only that, but stronger triceps help you smash various compound exercises, like the bench press, as they help with lockout strength and shoulder stability. 

Tricep dips and skull crushers are two of the top exercises for adding strength and size to the back of your arm. But is one superior to the other? With the help of an expert, we try and answer that very question.

Tricep dip vs skull crushers: what's the difference?

Tricep dips are a bodyweight exercise that are often performed on a dip station and target the tricep's medial head (located just below the long head) and lateral head (located on the outer portion of the tricep). They’re a compound exercise, so they fire up more muscles than just your triceps. “Dips also recruit your upper arms, front delts, and your pectoral muscles,” says Nick Mitchell, Founder of Ultimate Performance.

Alternatively, skull crushers are an isolation exercise, so they only target the triceps. “Don’t be put off by the name though, a skull crusher is just another name for a lying triceps extension,” explains Nick. They can be performed with various bits of equipment, but they’re commonly performed with either a pair of dumbbells or an EZ bar. Unlike dips, skull crushers target all three heads of the triceps, so the medial head, lateral head, and long head (located on the inner portion of the arm).

Tricep dip vs skull crushers: benefits

One of the great things about tricep dips is that they’re a scalable exercise that you can make easier or more challenging. “You can use chains, weighted belts or if you really want to feel the burn, you can slow down the eccentric portion of the dip to three or four seconds,” says Nick. Plus, you can even loop a resistance band around a dip station for extra assistance. 

They can be performed on various bits of equipment too (yes you don’t need a dip station). Nick suggests placing two weight benches parallel to each other, with your feet on one bench and your arms on the other, so that you to replicate the same movement. No weight benches free? You can even do them from the floor.

Similarly, you can use a mixture of equipment to perform skull crushers, from cable machines to barbells, and dumbbells. “This means you can progressively increase the weight, which will constantly challenge your muscles to adapt and grow,” says Nick. You can still easily perform skull crushers from the floor too, the only caveat is you need some form of weight to perform the exercise. 

Is one move easier than the other though? Well, tricep dips are challenging, as they require you to be able to control your own body weight and remain stable. However, don’t let this put you off: “This will have a strong carryover to exercises like the deadlift, where your entire body needs to be working efficiently together to lift the load,” says Nick. Whereas, with skull crushers, you can easily pick a weight that’s suitable for you, and have the support of the weight bench too, but you need to nail the form (and people tend to ego lift), otherwise they're pointless.

How to do tricep dips and skull crushers

Both these exercises require good form if you want to reap their benefits and encourage hypertrophy. Here's how to do each one, followed by some tips from Nick.

How to do tricep dips

• Grab the bars of the dip station with a neutral grip (palms facing inward)
• Keeping your elbows tucked in, lower yourself towards the floor so until you have a 90-degree angle at the elbow
• Hold here for a second, then push yourself back up and repeat

Nick's tips: 

• Don't lean forward too much (this puts more emphasis on the chest)
• Try to keep your upper back engaged throughout to keep your shoulders in the right position
• Always focus on keeping constant tension in the triceps, so don’t lock out at the bottom of the dip.

How to do skull crushers

• Sit on a weight bench holding either a pair of dumbbells or an EZ bar
• With weights in hand, lay backwards onto the bench and extend your arms above your head 
• Slowly bend your elbow towards your shoulders until they are fully flexed, trying to keep constant tension in the triceps
• Return to the start position, then repeat

Nick's tips:

• Start light and do it right
• I recommend three seconds for the lowering portion of the move and really focus on keeping the tension in those triceps muscles
• Don’t allow your elbows to flare out as you press

Tricep dip vs skull crushers: which is best for building your arms?

If your goal is simply to thicken your arms and look good in T-shirts, Nick says you’re best opting for skull crushers. “Out of the three triceps heads, the long head is the one you really want to target if you want to increase the density, thickness, and size of your triceps, and skull crushers target this more,” he says. “Also, you can incrementally increase the weights which will drive hypertrophy.”

This doesn’t mean tricep dips suck (far from it) as Nick says they still “trash your triceps”. Nick says the time you may opt for dips over skull crushers is if you’re pushed for time and need to smash through an upper body session, as they target multiple muscles, or if you don’t own any home gym equipment. 

“As a general rule, I would say that skull crushers are more effective are building overall strength in your triceps muscles, simply because it is a single-joint move that really isolates the long head,” he says. "But I would try to look at the two exercises as complimentary, rather than mutually exclusive and including both exercises in any workout is going to give you the most bang for your buck."