The same demo you get in the GymAdapt app for this exercise.
How to do it
What it should feel like
The back of the upper arm working hard, with a deep stretch at the bottom. No pain inside the elbow.
Common mistakes
- Flaring elbows. Keep them pointing toward your feet, roughly shoulder width.
- Moving the upper arms. That turns it into a pullover. Keep them fixed.
- Too heavy. Elbows complain first. Use a weight you can control for 8 or more reps.
- Fast reps. Lower under control, especially near your head.
Variations
Cable triceps work that is easy on the elbows.
Bodyweight triceps work.
Compound pressing that hits the triceps hard.
Sets, reps and programming
| Goal | Sets × reps | Effort | Rest |
|---|---|---|---|
| Muscle | 3 × 8–15 | 0–2 reps in reserve | 60–90 s |
| Small muscles (delts, calves) | 3–4 × 12–20 | 0–2 reps in reserve | 45–75 s |
| Learning it | 2 × 12–15, light | Slow, 1 s squeeze | 60 s |
An EZ bar is usually more comfortable on the wrists than a straight bar. The simplest rule that works: add reps inside the range first, and once every set hits the top of the range, add weight next session. GymAdapt does this for you from the sets you log, and tells you why the target changed.
Questions people ask
What do skull crushers work?
The triceps, especially the long head on the back of the upper arm.
Are skull crushers bad for your elbows?
Not when done with control and a sensible weight. Going too heavy or flaring the elbows is what causes trouble.
Should I lower to my forehead or behind my head?
Just behind the head gives a bigger stretch and keeps tension on the triceps; to the forehead is fine too.
How many sets and reps for skull crushers?
3 sets of 8 to 12 reps.
GymAdapt is free to start. Want Pro free for a month?
The free version gives you an AI-built plan and unlimited workouts. Code TRYFREE01 adds a full month of Pro on top: weights that adjust from what you log and unlimited coach chats.
Redeem the free month → Opens the App Store with the code filled in. iPhone only. After the month it's $4.99/mo unless you cancel in Settings, and the free version stays yours either way.Every exercise in GymAdapt comes with a demo like this, plus a target that moves.
An AI plan for your goal and equipment, a video for every lift, and next session's weight set from what you logged.
Get GymAdapt on the App Store → Free to start. Pro is $4.99 a month or $24.99 a year (7-day free trial), or $79.99 once for lifetime. iPhone only.