FitCi
Lying Triceps Extension (Skull Crusher) is an isolation exercise for the triceps: one joint works, so it comes after the compound lifts to finish the target muscle. Equipment: barbell, dumbbell. Difficulty: intermediate, add it once the basics are solid. It takes 5 steps; the most common mistake is covered in the tip below.
Step-by-step
- Lie on your back and hold the bar or dumbbells over your chest at shoulder width.
- Start with your arms straight and your upper arms perpendicular to the floor.
- Keeping your upper arms still, lower the weight toward your forehead or just past your head.
- Stop when your elbows reach about 90 degrees.
- Press the weight back up to the starting position using your triceps.
Coaching tip
Keep your upper arms vertical; lower the bar or weight toward your forehead.
Caution
Skip this move or ask a professional first if you have pain or an injury in: elbow, wrist. FitCi filters it out of your program automatically based on the injuries in your profile.
How to program it
Sets × reps and rest by goal; tempo and controlled reps matter most on isolation work. Start at the bottom of the range in week one; add 2.5–5% when you hit the top with clean form.
| Goal | Sets × Reps | Rest |
|---|---|---|
| Strength | 3 × 6-8 | 120 s |
| Muscle gain | 3 × 10-15 | 75 s |
| Fat loss / conditioning | 3 × 12-15 | 60 s |
FitCi applies this table to your age and goal automatically and writes weekly progression.
Alternatives
- At home, no equipment: Bench Dips, Diamond Push-Up
- Same muscle, different equipment: Triceps Dips, Bench Dips, Cable Triceps Pushdown
More triceps exercises
Add this exercise to your program
Build your own program in FitCi, pick an expert template, or photograph the plan your coach gave you; the app tracks sets, reps and weight.