What Is a Skull Crusher?

A skull crusher is a weight lifting exercise that works the triceps muscles on the back of the upper arm. They are called "skull crusher" because of the way the weight is lowered toward you head. It is a bit of a bad joke. You are not actually crushing your skull, but you would if you let go of the weight while doing the exercise. The skull crusher can be performed almost anywhere with a variety of different weight types.

Function

To perform the skull crusher exercise, pick up weights with an overhand grip. Lie flat on your back on a weight lifting bench or other flat surface. Raise both arms straight up above your chest. Your arms should be perpendicular to your body. This is your starting position. Bend both elbows and carefully lower the weight toward your head. Keep your upper arm perpendicular to your body as you do this. Only your forearms should move as you bend your elbows. When your arms are bent at a 90 degree angle, raise the weight again to the starting position. This is one repetition of the skull crusher exercise.

Types

The skull crusher exercise can be performed with dumbbells, a barbell or an EZ curl bar. Dumbbells are safest since they allow you to drop the weight if it gets too heavy. Barbells force your wrists to remain in a stationary position. An EZ curl bar does the same but lets your wrists turn at a more comfortable angle. The skull crusher exercise can be done while lying down on any flat surface, but a padded weight bench is the most comfortable.

Effects

The skull crusher exercise develops the triceps brachii. This is a three headed muscle group used when you straighten your arm at the elbow. The skull crusher exercise is excellent for building and defining the triceps. Many weight lifters focus on their biceps thinking they make the arms look big and strong. In reality it is the triceps that make up about two-thirds of the girth of the upper arm.

Size

You should use a relatively small size weight for the skull crusher exercise. The triceps are a small muscle group and do not require heavy weights. In fact, heavy weights will prevent you from using good form and wont work your triceps properly. If you have trouble lowering the weight or must bend your back and swing the weight up, it is too heavy.

Warning

The exercise is called skull crusher for a good reason. If you drop the weight while performing the exercise you will crush your skull. Start with very light weights and gradually increase the weight as you feel comfortable. If keeping good form ever becomes difficult, then decrease the weight. With the skull crusher exercise safety is always the most important concern.