The Complete Skull Crushers Guide: How to Do Them Right and Which Bar to Use
Skull crushers are one of the most effective tricep exercises ever devised and one of the most frequently butchered. The name alone puts people off — which is unfortunate, because when done correctly they are among the safest, most direct ways to develop tricep mass and lockout strength available. When done incorrectly, the name starts to feel apt.
This guide covers everything: what skull crushers are, why they work, the exact technique, the programming, and — critically — which bar to use, because the bar choice on skull crushers matters more than on almost any other exercise.
What are skull crushers?
Skull crushers — also known as lying tricep extensions, French press, or EZ bar tricep extensions — are an isolation exercise for the triceps performed lying on a bench. The bar starts at arms-length overhead, and is lowered toward the forehead (or slightly behind it) by bending the elbows, before being pressed back to the start. The upper arms stay fixed and vertical throughout; all the movement happens at the elbow joint.
The name comes from what happens if you lose control — something worth not experiencing. In practice, controlled skull crushers with an appropriate weight are no more dangerous than any other barbell exercise. The risk management is mostly about bar choice and loading, both of which this guide addresses directly.
Why skull crushers are worth doing
The triceps make up roughly two-thirds of upper arm mass. If arm size is the goal, the triceps are doing more of the work than the biceps — which surprises most beginners, who spend the majority of their arm training on curls. More importantly for strength athletes, the triceps are the primary driver of lockout in both the bench press and the overhead press. Weak triceps mean missed lifts at the top, not the bottom.
Skull crushers develop the long head of the tricep more effectively than pressdowns and other elbow extension movements performed in a shortened position. When the arm is overhead — as in a skull crusher — the long head is placed under a stretch that elbow pressdowns at the cable stack cannot replicate. This stretched position under load is one of the most powerful stimuli for muscle growth available, which is why skull crushers produce results that cable pressdowns, despite their popularity, struggle to match for pure mass development.
The exercise also trains all three heads of the tricep simultaneously — long head, lateral head, and medial head — making it a comprehensive tricep movement rather than a partial one.
Skull crusher technique: how to do them correctly
Set up: lie on a flat bench with your feet flat on the floor. The bar should start held at arms-length directly over the shoulder joint, not over the chest. Upper arms should be perpendicular to the floor or very slightly inclined toward the head — this keeps the long head under load throughout the movement.
The descent: bend at the elbows only. The upper arms stay fixed and vertical. Lower the bar toward the forehead, or slightly behind the head — lowering behind the forehead rather than to it increases the range of motion and the stretch on the long head, and is the variation preferred by most experienced lifters for mass development. The bar should travel to within a few centimetres of the skull or slightly past it.
The ascent: extend the elbows to press the bar back to the start. Squeeze the triceps at the top. Do not flare the elbows outward during the movement — elbow flare shifts work away from the triceps and onto the chest and shoulder.
What not to do: using the shoulder to compensate (the upper arm moving rather than staying fixed), bouncing the bar off the forehead, using too much weight and losing control of the elbow position, and going too fast through the eccentric portion. Skull crushers respond well to a controlled eccentric — two to three seconds down — which increases time under tension and maximises the stimulus on the long head.
Which bar to use for skull crushers — and why it matters
Bar choice on skull crushers is not cosmetic. The grip angle, shaft diameter, weight of the bar, and sleeve type all affect wrist and elbow comfort, the range of motion available, and how much load can be used productively. These are the options:
The most widely used bar for skull crushers and the best starting point for most people. The angled grip positions of the EZ bar place the wrists in a semi-supinated position — partway between fully supinated (palms up) and fully pronated (palms down). This immediately reduces the torque placed on the wrist and elbow joint compared to a straight bar, making the exercise more comfortable for the overwhelming majority of lifters.
The practical result: you can train with more focus on the tricep contraction and less on managing wrist discomfort, particularly as the weight gets heavier. The EZ bar also allows a narrower effective grip than a straight barbell, which keeps the elbows more naturally aligned for tricep isolation.
Specs: 1200mm length, 6.7kg, 25.4mm shaft, 50mm sleeves compatible with all Olympic plates, steel bushing rotating sleeves, black E-coating finish with 2-year warranty.
The E-coating is worth noting — harder wearing than black oxide, chrome, and zinc, resistant to corrosion, oxidation and everyday wear. This is the bar you use daily for years, not the one that starts looking rough after six months.
The heavy-duty option. At 12kg and 135cm with a 28mm shaft and needle bearings, this bar is built for serious training loads. The 26cm loadable sleeve length means significantly more plates can be loaded than a standard EZ bar allows — directly relevant when skull crushers get heavy and you need 25kg or more per side.
The needle bearing sleeve rotation is the meaningful engineering upgrade over bushing-based bars: smoother sleeve rotation means less friction and a more consistent bar path under load, which matters on a skull crusher where any lateral drift in the bar exacerbates elbow and wrist strain. The 150kg max suggested load and 155,000 PSI steel give confidence for progressive loading over a long training career.
Best for: lifters who skull crush heavy, intermediate to advanced athletes, anyone training at a volume where the bar will see significant daily use.
The specialist option. At 50mm shaft diameter and 13kg, this bar trains the triceps and the grip simultaneously. The thicker shaft recruits significantly more forearm and hand musculature throughout the movement — which some lifters actively want, and others do not.
For skull crushers specifically: the thick shaft changes the feel of the exercise considerably. Those with strong forearms and established grip capacity will find it adds a productive extra stimulus. Those newer to training or with limited grip strength will find the grip fatigue limits the tricep training before the tricep does. This bar rewards being earned — start with one of the standard EZ options, develop baseline skull crusher strength, then add the thick bar as a variation.
The ergonomic EZ curve and rotating Olympic sleeves are present here too, so the joint-friendly angle advantage over a straight bar is retained.
The most wrist-friendly option on this list and the one that changes the exercise most fundamentally. The tricep bar — also called a football bar or hex bar for tricep work — allows a neutral grip: palms facing each other, thumbs up. This is the position in which the wrist is under least biomechanical stress, which makes it the correct choice for anyone dealing with existing wrist discomfort or recovering from a wrist or elbow issue.
The neutral grip changes the muscle emphasis slightly compared to the EZ bar — the lateral and medial heads of the tricep become more prominent, and the long head slightly less so, though all three heads are still worked. For bodybuilders chasing specific head development, this distinction is worth knowing. For general tricep mass and strength development, it makes very little practical difference.
Specs: 9kg, 86cm total length, 19cm wide, 18cm between handles, 25mm handle diameter, E-coating, 50mm sleeves. The compact length (86cm) makes it easy to handle on a bench, particularly in a home gym where space may be tighter.
The most joint-friendly and mechanically unique option. The freely rotating handles mean the wrist finds its own natural position throughout each rep rather than being locked into a fixed angle — the biological equivalent of removing a fixed constraint and letting the joint self-select its most comfortable path. For lifters with wrist mobility limitations, previous injuries, or simply chronic discomfort on fixed-grip bars, this bar frequently allows skull crushers to be trained pain-free when nothing else does.
The dual function — use as a standalone curl bar or attach to a cable pulley for tricep pushdowns, curls, and rows — extends its utility significantly for home gym setups. On the cable, rotating handle skull crushers (or cable overhead tricep extensions, which share the same mechanics) provide a continuous tension variation that the free weight version doesn't offer.
Specs: 1200mm total length, 25mm shaft, approximately 16.6kg, 50mm Olympic sleeves, 150kg max load.
Bar comparison: which to choose
| Bar | Grip type | Best for | Wrist friendliness | Shaft diameter |
|---|---|---|---|---|
| EZ Curl Bar | Semi-supinated | Most lifters, everyday use | ✓✓✓ | 25.4mm |
| Riot EZ Curl Bar | Semi-supinated | Heavy loading, advanced | ✓✓✓ | 28mm |
| Thick EZ Curl Bar | Semi-supinated | Grip + tricep combined | ✓✓ | 50mm |
| Tricep Bar | Neutral | Wrist issues, lateral head emphasis | ✓✓✓✓ | 25mm |
| Rotating Handle Bar | Self-selecting | Injury rehab, max comfort | ✓✓✓✓✓ | 25mm |
Programming skull crushers: sets, reps and frequency
Skull crushers are a hypertrophy exercise — they respond best to moderate to higher rep ranges rather than the low-rep heavy loading appropriate for compound movements. The most productive rep ranges are 8–15 reps, with sets taken close to failure (1–2 reps in reserve). Going below 6 reps with very heavy loading on skull crushers increases elbow stress disproportionately relative to the training benefit.
Frequency: two to three times per week is appropriate if skull crushers are the primary tricep exercise. Once per week works if they're one of several tricep movements in a programme that already includes heavy bench press, which provides substantial indirect tricep stimulus.
Volume: 3–4 working sets per session is the productive range for most intermediate lifters. Beginners can start with 2–3 sets. Advanced lifters chasing hypertrophy may go higher, but elbow joint tolerance is the limiting factor rather than muscular capacity — the elbow responds more slowly to training stress than muscle tissue, and exceeding its adaptive capacity produces tendinopathy.
A reliable skull crusher superset: skull crushers followed immediately by close-grip bench press. The skull crusher pre-fatigues the tricep through the long-head stretch, and the close-grip bench press follows up with a heavier compound movement while the tricep is already stimulated. This combination is one of the most efficient tricep training pairings available.
Common skull crusher mistakes and how to fix them
Upper arms drifting back: the most common fault, and the one that reduces tricep involvement by shifting the load onto the shoulder. Fix: consciously keep the upper arms perpendicular to the floor and still throughout — video yourself from the side to confirm.
Bar drifting toward the chest: related to elbow flare. Fix: keep elbows pointing directly at the ceiling throughout the movement, not flaring outward.
Too much weight: manifests as loss of elbow position, bar bouncing, and compensation through the shoulder. Fix: reduce load until all reps are clean, then rebuild gradually. Skull crushers with sloppy technique load the elbow joint in exactly the wrong way.
Using a straight bar when the wrists complain: the straight bar requires full pronation through the skull crusher, which is not the natural wrist position under elbow stress. Fix: switch to an EZ bar or tricep bar. Joint discomfort on skull crushers is almost always solved by bar selection rather than by gritting through it.
Skipping the eccentric: rushing through the lowering phase wastes the most productive part of the movement. Fix: three seconds down, controlled at the bottom, press back up.
FAQ
Are skull crushers safe?
Yes, when performed with correct technique and an appropriate bar. The name is theatrical — controlled skull crushers with an EZ bar or tricep bar, loaded sensibly and performed with full elbow control, are no more inherently dangerous than a dumbbell press. The risk increases with too much weight, sloppy elbow control, and using a bar that forces the wrist into an uncomfortable fixed position.
Should skull crushers go to the forehead or behind the head?
Both are valid. To the forehead is the classic variation and safe. Behind the head increases range of motion and long head stretch, producing a slightly greater hypertrophic stimulus. Start with to-the-forehead until the movement is reliable, then experiment with lowering further behind the head.
Can I do skull crushers with a straight barbell?
Yes, but it's the worst option on this list for most people. The straight bar requires full pronation, which places more stress on the wrist and elbow than the semi-supinated EZ position. Use a straight bar only if the other options genuinely aren't available.
How heavy should skull crushers be?
Heavy enough that the last two reps of each set are genuinely hard, light enough that technique doesn't break down. As a rough guide: if you bench press 80kg for reps, working skull crusher weight is typically 30–45kg including bar. The skull crusher is an isolation exercise, not a max effort movement — the load should be appropriate to that function.
Do skull crushers build mass or just strength?
Both, but they're better for mass than for raw strength in isolation. The stretched position under load on the long head is a powerful hypertrophic stimulus. For strength, the skull crusher builds the tricep mass that translates to bench press lockout strength — so it contributes to strength gains indirectly but meaningfully.
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