Dumbbell Skull Crushers (How To, Muscles Worked, Benefits)

Dumbbell Skull Crushers are a great triceps exercise that can be done with nothing more than a set of dumbbells.

Here’s how to do DB Skull Crushers, what muscles the exercise works and a few alternatives if you’re unable to do them.

How To Do DB Skull Crushers

Dumbbell Skull Crushers are an isolation exercise that directly targets the triceps, helping to build size and strength in the back of the upper arms. Using dumbbells allows each arm to work independently, improving muscle balance and range of motion compared to a barbell. It’s a solid move for rounding out your arm training.

Primary Muscles Worked: Triceps Brachii
Secondary Muscles Worked: Forearms, Shoulders (Stabilizers)
Equipment Needed: Dumbbells, Flat Bench (optional)

---

Step-by-Step Instructions

1. Set-Up:
   • Lie flat on a bench or on the floor, holding a dumbbell in each hand.
   • Extend your arms straight up over your shoulders with your palms facing each other.
2. Execution:
   • Keeping your upper arms stationary, bend at the elbows to slowly lower the dumbbells toward your temples or just outside your ears.
   • Press the dumbbells back up by extending your elbows until your arms are fully extended.
3. Tips for Proper Form:
   • Keep your elbows in and avoid letting them flare out to the sides.
   • Move only at the elbow joint—your upper arms should stay fixed.
   • Lower the dumbbells slowly and under control to avoid strain on the elbows.

---

Key Benefits

• Isolates the triceps for focused arm development.
• Allows for a deep stretch and strong contraction through the full range of motion.
• Dumbbells offer better joint freedom and can reduce strain on the wrists and elbows.

---

Modifications and Variations

• Easier Option: Use lighter dumbbells or reduce range of motion to stay within a comfortable range.
• Harder Option: Use heavier weight, add a pause at the bottom, or perform on an incline bench to change the angle of resistance.

---

Common Mistakes

• Flaring Elbows: Keep elbows tucked to keep the tension on your triceps.
• Moving the Upper Arms: Focus on only bending at the elbow—don’t turn it into a press.
• Letting the Dumbbells Drop Too Low: Stay in control to avoid elbow or shoulder strain.

---

Reps and Sets Recommendations

• For Beginners: 3 sets of 10–12 reps with light dumbbells.
• For Strength: 3–4 sets of 6–8 reps with heavier weight.
• For Hypertrophy: 3–4 sets of 8–12 reps focusing on slow, controlled movement and a good squeeze at the top.

DB Skull Crusher Alternatives

If you’re not able to do DB Skull Crushers (or maybe you just want to change your workout up a bit), here are a few alternatives.

If you’d like even more options, check out my 10 favorite dumbbell skull crusher alternatives.

Barbell Skull Crushers

The most natural alternative for Dumbbell Skull Crushers is Barbell Skull Crushers with a bar. You can use a straight barbell or an EZ Curl Bar (shown above) although most lifters prefer a Curl Bar because of the angle it allows the wrist to turn.

If you don’t have dumbbells, but you have a bar, this would be my first recommendation.

Dips

If you have access to a dip rack attachment or a dip station, Dips are one of the best exercises you can do to build triceps strength.

Band Triceps Pushdowns

Don’t have dumbbells, but have a resistance band? Hang the band off a rack or pull-up bar and do Band Triceps Pushdowns instead.

More Links and Info

If you’d like step-by-step instructions for more biceps and triceps exercises, check out the Arm Farm section of the Exercise Library.

Share This