Skull Crushers: How to Do It, Muscles Worked & Benefits
Animated demoSkull crushers (lying triceps extensions) are done lying on a bench, lowering an EZ bar toward your forehead and extending the arms. They stretch and load the long head of the triceps for great growth.
What is the skull crushers?
Skull crushers (lying triceps extensions) are done lying on a bench, lowering an EZ bar toward your forehead and extending the arms. They stretch and load the long head of the triceps for great growth.
The skull crushers is beginner-friendly and a isolation movement. Isolation exercises move one main joint, which lets you focus on a specific muscle, fix weak points and add extra training volume without tiring the whole body. You can do it in a gym, which makes it easy to fit into almost any routine.
Muscles worked
The main muscles trained by the skull crushers are the triceps, with help from the forearms.
Triceps (primary)
The triceps make up about two-thirds of the upper arm. They straighten the elbow and help in every pushing movement, from push-ups to the bench press.
Forearms (secondary)
The forearm muscles control the wrist and fingers. They power your grip, which limits how much you can lift in pulls, rows and deadlifts.
How to do the skull crushers: step by step
- Using a close grip, lift the EZ bar and hold it with your elbows in as you lie on the bench. Your arms should be perpendicular to the floor. This will be your starting position.
- Keeping the upper arms stationary, lower the bar by allowing the elbows to flex. Inhale as you perform this portion of the movement. Pause once the bar is directly above the forehead.
- Lift the bar back to the starting position by extending the elbow and exhaling.
- Repeat.
Coach’s note: Practice the first sessions with a light load or an easier variation. Perfect technique first, then add reps, then add weight.
Benefits of the skull crushers
- Strong triceps mass builder
- Stretches the long head of the triceps
- Works with EZ bar or dumbbells
- Builds lockout strength
Like all resistance training, the skull crushers also contributes to the general health benefits of strength work: stronger bones, better blood-sugar control, improved mood and a higher resting metabolism over time. The U.S. Physical Activity Guidelines recommend muscle-strengthening activities for all major muscle groups on two or more days per week for adults.
Common mistakes to avoid
- Elbows flaring wide
- Moving the upper arms too much
- Too heavy (elbow pain)
- Dropping the bar fast
Most of these mistakes happen when the weight is too heavy or when you rush. Film one set from the side with your phone. It is the fastest way to spot form problems without a coach.
Form tips from a trainer
- Upper arms slightly tilted back, not straight up
- Lower the bar to just behind the head
- Keep the elbows pointing up
- Use moderate weight and control
How to breathe
Breathe in as you lower the weight or your body (the easier phase) and breathe out as you push. For heavy sets, take a big breath into your belly before the rep, brace your core, and breathe out near the end of the push.
Sets and reps by fitness level
| Level | Sets × reps | Rest | Frequency |
|---|---|---|---|
| Beginner | 3 × 10 light | 60–90 sec | 2× per week |
| Intermediate | 3 × 10–12 | 60–120 sec | 2× per week |
| Advanced | 4 × 8–12 | 90–180 sec | 2–3× per week |
Choose a load or variation where the last 1–3 reps of each set feel hard but your form stays clean. When you can do the top of the rep range for every set, make it harder: add weight, add reps, slow the tempo or move to a harder variation. This is called progressive overload, and it is the main driver of strength and muscle gains.
Easier and harder variations
Make it easier
- Dumbbell skull crushers
Make it harder
- Incline skull crushers
Skull Crushers for men and women
The technique of the skull crushers is the same for men and women. The difference is in programming. Men often aim for more upper-body size and use heavier loads with lower reps, while many women prefer more lower-body and glute volume and moderate loads with higher reps. Both approaches work. Muscle responds to effort and progressive overload regardless of gender, and women typically recover a little faster between sets.
You will find this exercise in these HelloMyTrainer programs:
- Men's Intermediate Gym Program (4-Day Upper / Lower Split)
- Advanced Push / Pull / Legs Gym Program for Men (6 Days)
Safety tips
- Warm up for 5–10 minutes before your first working set: light cardio plus a few easy reps.
- Stop immediately if you feel sharp, stabbing or joint pain. Muscle burn is normal; pain is not.
- If you have an injury, are pregnant, or have a heart, blood-pressure or joint condition, ask your doctor or a physical therapist before doing this exercise.
- Use safety pins, safety arms or a spotter whenever you lift a barbell close to your limit.
Frequently asked questions
What muscles does the skull crushers work?
The skull crushers mainly works the triceps, with the forearms helping.
Is the skull crushers good for beginners?
Yes. It is a beginner-friendly exercise. Start with the beginner sets and reps above and focus on clean technique.
How many sets and reps of the skull crushers should I do?
Beginners: 3 × 10 light. Intermediate: 3 × 10–12. Advanced: 4 × 8–12. Train each muscle group about twice per week.
Can I do the skull crushers at home?
This version needs gym equipment. At home, try Dumbbell skull crushers instead.
How often should I train with the skull crushers?
Two to three times per week is ideal for most people, with at least 48 hours between hard sessions for the same muscle group.
Related exercises
Animated demoClose-Grip (Diamond) Push-Ups
Placing your hands close together under your chest turns the push-up into one of the best bodyweight triceps exercises.
Animated demoBench Dips
Bench dips use a bench, chair or couch to train the triceps with your body weight.
Animated demo