The goal with Skull Crusher is simple—make every repetition look repeatable from the same stable start. The exercise mainly trains triceps long head, while front delts help support and control the movement. You will use a barbell and a flat bench while working from supine on the bench.
What makes a good Skull Crusher repetition?
Keep the upper arm controlled and finish through elbow extension without forcing a hard lockout. The movement is approachable once the setup is familiar, but balance, load control, or multi-joint coordination make clean repetitions more demanding.
Muscles worked
Primary
Triceps long head
These muscles should carry most of the intended work when the setup and movement path stay consistent.
Supporting
Front delts
These muscles assist the movement or help keep the rest of your position steady.
Set up before you move
Start from supine on the bench. Use the prescribed grip: secure, exercise-appropriate grip. Check that a barbell and a flat bench are secure and adjusted before you begin.
Step-by-step tutorial
How to do Skull Crusher
- 1
Set the starting position
Take the Skull Crusher position with barbell and flat bench, brace the trunk, stabilize the shoulders, and point the elbows along the intended path.
Breathing: Breathe steadily; do not hold your breath.
- 2
Perform the effort phase
Exhale and extend the elbows for Skull Crusher; keep the upper arms controlled and avoid using torso momentum.
Breathing: Exhale through the effort.
- 3
Control the end position
Finish with the elbows straight but not forcefully locked, shoulders stable, and wrists aligned with the forearms.
Breathing: Breathe steadily; do not hold your breath.
- 4
Return under control
Inhale and bend the elbows under control until the triceps are lengthened and the exact starting alignment is restored.
Breathing: Inhale through the controlled return.
Common mistakes to avoid
Starting before the setup is stable
Do not rush the first position. Take the Skull Crusher position with barbell and flat bench, brace the trunk, stabilize the shoulders, and point the elbows along the intended path. Make that setup feel repeatable before adding speed or resistance.
Letting the working position drift
Keep your supine on the bench setup consistent through the rep and maintain the secure, exercise-appropriate grip. If another part of the body has to swing or twist, reduce the load or range.
Rushing the return
The return is part of the exercise, not a pause between efforts. Inhale and bend the elbows under control until the triceps are lengthened and the exact starting alignment is restored.
Forcing a range you cannot control
Use the Skull Crusher setup, maintain controlled joint alignment, and stop if the movement causes pain.
Sets, reps, and rest
Start with 2–4 sets of 10–15 smooth repetitions. Rest 45–90 seconds between sets. Use enough resistance to feel the target muscles without shortening the range or borrowing momentum from the rest of your body.
Treat this as a starting framework. Your load and volume should match your current technique, recovery, and training plan.
Skull Crusher questions
Is Skull Crusher suitable for beginners?
Skull Crusher is classified as an intermediate-level movement in this guide. The movement is approachable once the setup is familiar, but balance, load control, or multi-joint coordination make clean repetitions more demanding.
What muscles does Skull Crusher work?
Skull Crusher primarily works triceps long head, with front delts assisting or stabilizing the movement.
What equipment do I need for Skull Crusher?
You need a barbell and a flat bench. Set everything up securely before the first repetition.
