Skull Crushers
The skull crusher is a lying triceps extension done with an EZ bar. You lower the bar towards your forehead by bending only at the elbows, then straighten your arms to press it back up. It builds the triceps at the back of the upper arm and suits beginners who have learned the basics of pressing, as well as experienced lifters adding arm volume.
Muscles worked
The Skull Crushers mainly works your triceps.
Setting up
- Set a flat bench and load the EZ bar with light weights, fixed with collars. Start much lighter than you think you need, as this exercise is about control rather than load.
- Lie back with your eyes roughly under the bar's start position, feet flat on the floor, glutes and upper back in contact with the bench, and a slight natural arch in your lower back.
- Take the bar with a narrow grip on the inner angled sections, palms facing forward and angled slightly inwards, thumbs wrapped around the bar.
- If you are lifting heavier, ask a spotter to hand you the bar. Otherwise, sit up with the bar on your thighs and lie back, bringing it over your chest.
How to do the Skull Crushers
- Hold the bar directly above your chest with your arms straight but elbows not locked hard, and your upper arms vertical.
- Brace your core and squeeze the bar firmly, keeping your wrists straight and stacked over your forearms.
- Bend at the elbows only, lowering the bar slowly towards your forehead or just behind the top of your head, while your upper arms stay still.
- Stop when the bar is a few centimetres from your head, or when you feel a good stretch in the back of your arms.
- Drive the bar back up by straightening your elbows, thinking about pushing your triceps through the bar.
- Pause briefly at the top with your arms straight, squeeze your triceps, then repeat for the rest of your reps.
Form tips
- Keep your elbows pointing at the ceiling and about shoulder-width apart. If they flare out wide, the movement drifts away from the triceps.
- Lower the bar over about two to three seconds. A slow, controlled descent keeps the tension on your triceps and the bar under control.
- Imagine your upper arms are fixed in place, like hinges. Only your forearms should move.
- Keep your wrists firm and neutral so the bar does not bend them back. The angled EZ bar grip is there to keep your wrists comfortable, so use it.
- Choose a weight you can lift for every rep with the same smooth movement. If your elbows start drifting or the bar wobbles, it is too heavy.
Common mistakes
Elbows flaring out
Think about pointing your elbows at the ceiling and keeping them roughly shoulder-width apart. Reduce the weight until you can hold this position through every rep.
Upper arms drifting back overhead
Letting your arms travel back turns the exercise into a pullover-style movement and takes tension off the triceps. Keep your upper arms vertical and move only at the elbows.
Going too heavy and bouncing the bar
Lower the weight and slow the descent so there is no bounce at the bottom. Every rep should look the same, with a clear, controlled start to the upward drive.
Lowering the bar too fast towards your face
Take two to three seconds to lower the bar and stop a few centimetres from your head. If you cannot control the bar on the way down, drop the weight.
Sets and reps
| Build strength | 3-4 sets of 6-8 reps with a challenging but controlled weight, resting 2 minutes between sets. Do it after your main pressing work. |
|---|---|
| Build muscle | 3-4 sets of 8-12 reps, resting 60-90 seconds. Use a slow lowering phase and stop each set with a couple of reps still in reserve. |
| Fat loss and general fitness | 2-3 sets of 12-15 reps with a lighter weight, resting 45-60 seconds. Include it as part of a full-body or upper-body session alongside bigger exercises. |
Pick a weight where the last rep or two of each set is hard but your form stays clean. When every set feels easy, it's time to go up.
Skull Crushers alternatives
Machine taken, or want some variety? These work the same main muscles.
Skull Crushers FAQs
Why are they called skull crushers?
The name comes from lowering the bar towards your forehead. Used with sensible weight and control, it is a safe exercise, and many lifters lower the bar just behind the head instead of directly to the forehead. If the name worries you, you can also call them lying triceps extensions.
Should I lower the bar to my forehead or behind my head?
Either works. Lowering just behind the top of your head keeps more tension on the triceps at the bottom and the bar travels in a smoother path. Lowering to the forehead is the classic version. Pick the one that feels more controlled and comfortable for your elbows and shoulders.
What weight should a beginner use for skull crushers?
Start with just the empty EZ bar or a very light load, and aim for 10-12 smooth reps. Add small amounts of weight only when every rep looks the same. If you feel pain in your elbows or anywhere else, stop and get it checked.
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