Doing the Triceps Extension 'Skullcrusher'

The skullcrusher is a versatile triceps exercise with several variations

Extending the arms by flexing and extending the elbow joint in a rear or overhead motion while holding dumbbells or barbells or a weighted cable is called triceps extension.

The triceps extension often called the skullcrusher is an overhead extension performed while lying on a flat bench using a dumbbell, two dumbbells, or a barbell.

The skullcrusher gets the name because some exercisers perform it incorrectly by lowering the weight directly toward the forehead.

For further guidance you ca refer to the beginner's guide.


How to Perform the Skullcrusher

Overhead triceps exercise - starting position
Photo © Paul Rogers
  1. Choose a flat gym bench and lie face up with legs comfortably to each side on the floor or resting on the footrest. Select a position that provides comfort and stability.
  2. Select a single dumbbell of suitable weight.
  3. Hold the dumbbell with both hands above your chest, straight up, and with the dumbbell shaft in a vertical position. This is the starting position.
  4. Move the weight down toward the rear of your head with a flexing of the elbows – the motion takes place in the elbows, while upper arms generally remain perpendicular to the body. Keep the upper arms from moving back and forth with the weight as this transfers some of the work to the shoulders instead of focusing it on the triceps. Remember to start with a breath and exhale on exertion. 
  5. Continue lowering the weight behind the head until the dumbbell head is about in line with the bench top, or even a little higher if this feels unwieldy.
  6. Reverse the movement until the weight is held above the chest in the starting position again. Don't lock the elbows at the starting position; instead, stop just shy of locked position to maintain tension in your muscle. Repeat the exercise for the number of repetitions defined in your program.

Points to Note

Overhead triceps exercise - execution
Photo © Paul Rogers
  1. You can place your feet on the bench with knees flexed if this suits your body shape.
  2. You should aim for 10 to 12 extensions for each of 3 sets, or whatever you program indicates.
  3. You can clench the dumbbell with one hand over the other because most people will not fit two hands around a dumbbell shaft side by side.
  4. Make sure you have a firm grip because the skullcrusher will be traveling above the region of your head and face – you don't want to provide a literal demonstration of this exercise's figurative name.
  5. Don't lower the weight toward the face or forehead; it should travel behind your head. Ensure you pass the weight over the head. This exercise should be done slowly and carefully under good control.
  6. Keep the elbows in close and tight to the body. Flaring elbows is poor form, distributing the effort to other muscles.
  7. Take care not to impact the back of the head when raising the dumbbell from behind the head to return to the starting position.
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