The Critical Body logo

How to do TRX skull crushers for your triceps

Learn how to do a TRX skull crusher with the optimal tricep-building technique.
Written By  James Jackson
Last Updated on 18th September 2021
A man performing a TRX skull crusher for his triceps

The TRX skull crusher (also called the nose breaker exercise) is a challenging muscle-building movement for developing your triceps and strengthening your core.

But can this bodyweight skull crusher variation provoke as much muscle growth as the free weight versions?

You’ll soon find out.

TRX skull crusher exercise details

  • Also Known As: Suspension trainer skull crusher, TRX tricep extension
  • Main Muscles: Triceps brachii muscle
  • Secondary Muscles: Abs
  • Exercise Type: Strength
  • Exercise Mechanics: Isolation
  • Difficulty Level: Intermediate
  • Equipment Needed: TRX

How to do TRX skull crushers

  1. Suspend your TRX above head height.
  2. Stand facing away from the suspension point with your feet shoulder-width apart and grab the handles with a neutral grip.
  3. Lean forward slightly to create some resistance.
  4. Bend your elbows to move the handles behind your head.
  5. Descend slowly until you feel a really strong stretch in your triceps.
  6. Reverse the motion by pushing into the handles to extend your elbows.
  7. Squeeze your triceps once your elbows reach full extension.
  8. Perform 3-5 sets of 8-15 reps.

TRX skull crusher advantages

TRX skull crushers provide your triceps with plenty of resistance to grow bigger and stronger. Since your triceps only respond to tension, performing skull crushers on the TRX is just as effective as doing them with free weights.

Yet, there are a few ways in which TRX tricep skull crushers are actually better than the free weight variations.

These benefits are what you’re going to learn about now.

It increases your core strength

Man with a bar on his back looking at his abs

Having muscular arms is great, and a pair of well-defined triceps can really enhance your physique.

But without enough core strength, your muscles will just be for show because you won’t be able to stabilize your abs under heavy loads.

Thankfully, you don’t have to choose between a rock-solid core and muscular triceps with suspension trainer skull crushers; they work your triceps and your abs excellently.

This is one reason why TRX BW skull crushers can challenge even the biggest bodybuilders (the other reason is that the resistance is always relative since it’s based on your body weight).

Free-weight skull crushers don’t activate as many stabilizer muscles as the TRX version because, when you’re using a suspension trainer, you need to contract your abs intensely in order to keep your torso stable.

Stability ball skull crushers are the exception to this. Although the exercise doesn’t require as much core strength as suspension trainer skull crushers, using a stability ball, as the name implies, requires you to contract your abs to keep your body stable.

It’s completely customizable

Sure, you can swap the plates around on free-weight skull crushers to increase or reduce the resistance, but it’s not as efficient as modifying the TRX tension.

You can make TRX skull crushers harder in multiple ways.

First off, you can simply lean further forward to increase the percentage of your body weight that’s used for resistance.

Second, you can slow down your negatives, which, in my opinion, you should actually do by default to increase the time under tension.

Also, if you’re used to moving the handles to your forehead, then you can lower them behind your head in order to intensify the stretch in the long head of your triceps. Again, this is something that you should do by default because you can literally double your range of motion by lowering the handles behind your head rather than merely moving them toward your forehead.

It targets the long head

A man showing the three heads of the triceps brachii muscle

It’s only when you actually develop the long head of the triceps on your own physique that you realize just how much mass it contributes to the upper arms.

While you can have nicely toned triceps by focusing on the lateral (outer) head, you need to develop the long (inner) head if you want to beef up your arms.

TRX skull crushers are one of the most effective exercises in this regard because there’s no limit on how far you can lower the handles behind your head.

The reason this behind-the-head stretch works so well is that, unlike the other two heads, the long head of the triceps actually performs shoulder extension as well as elbow extension.

So when you combine these two functions in the same exercise, you generate a really potent muscle-building stimulus for the major head of your triceps.

It’s a safe exercise

Performing skull crushers on a TRX is safer than doing them with free weights because you can’t suddenly drop a bar on your face.

Unlike a barbell, you can also hold the TRX handles with a neutral grip to ease the pressure on your wrists.

Using a TRX for skull crushers doesn’t completely eradicate the elbow discomfort that some people experience on this exercise, but, in my experience, it does lessen it significantly.

You can take this safety a step further by really controlling your reps with your triceps rather than just moving your hands from Point A to Point B.

Variation: TRX single arm skull crusher

A man doing a one arm TRX skull crusher

I’ve seen a few people asking about the single hand TRX skull crusher.

Here’s my opinion on the exercise.

The one arm TRX skull crusher requires extreme amounts of core strength to execute correctly, far beyond what most people can hope to develop.

Secondly, the exercise is very harsh on the elbows because all the force is going through that one elbow joint rather than being dispersed over the usual two.

Moreover, even if you can do a rep or two, you’re simply not going to be able to perform enough reps to make the exercise worthwhile.

For these reasons, you’re much better off sticking with regular, two-arm TRX skull crushers. If you want to make the movement more challenging, then you can implement the modifications recommended above. And if those don’t do the trick, then you can even wear a weighted vest.

Conclusion: Who should do TRX skull crushers?

Anyone who wants to strengthen their triceps can benefit from incorporating the TRX skull crusher into their workout program.

This is true regardless of whether you’re a bodybuilder or simply someone who’s trying to keep fit because TRX resistance, being based on your body weight, is always relative and thus accessible to people of different ability levels.

If you’re already really strong, then TRX skull crushers are a great way to burn out your triceps after a hard workout.

But for many people, TRX skull crushers are actually a tremendous primary tricep exercise since they provide such an intense, growth-stimulating stretch.

Just be sure to use controlled negatives to get the best results. Remember, it’s all about tension when you’re training with a TRX, and you can increase this tension by modifying the movement with greater torso lean and a bigger range of motion.

James Jackson
James Jackson is a personal trainer who uses his expertise in strength and conditioning to create helpful workout tutorials that show fitness enthusiasts how to build muscle while staying safe in the gym. He draws on the latest sports science data as well as tried and tested training techniques to get the best results for his clients without them having to live in the gym.
chevron-upmenu-circlecross-circle linkedin facebook pinterest youtube rss twitter instagram facebook-blank rss-blank linkedin-blank pinterest youtube twitter instagram