The skull crusher is an exercise that works your triceps muscles. Despite their intimidating name, it is a safe and effective upper-body isolation move. Also known as lying triceps extensions, there are a number of ways you can perform skull crushers to keep your training challenging and build bigger and stronger triceps. Look for ways to include skull crushers in your routine.
Barbell Skull Crushers
Any variation of the skull crusher involves lying on a weight bench and starting the move with weights in your hands and your arms held straight above your chest. For the barbell version, lower the bar toward your head while keeping your triceps still; the movement should happen in the elbows. Keep lowering the bar until it is just above your forehead, then return the weight back up to the starting position, focusing on your triceps muscles. You can use a regular straight bar or an EZ bar to complete the exercise. The EZ bar places less stress on your wrists, according to strength coach Mike Robertson.
Another option is to switch to dumbbells for the skull crusher. These are performed in almost exactly the same way, but with dumbbells instead of a bar. The only slight differences are that you turn your palms to face each other when holding the dumbbells and by using dumbbells you add in an element of instability, as your arms are working independently. This means you have to use less total weight. Using dumbbells will also show any strength imbalances between your arms. You can hold just one dumbbell in both hands, by holding the plates at the end of the dumbbell. This doesn't require as much stabilization as the two dumbbell version.
Changing the Angle
While skull crushers are typically performed on a flat bench, there's nothing stopping you from adjusting the angle. In fact, putting your bench on a decline, so your head is closer to the ground than your feet, enables you to get a better stretch in the triceps and increases the difficulty of the move. If you don't have access to a weight bench you can also perform skull crushers while lying on the floor.
Include skull crushers in your workouts once a week. They can either be part of a targeted triceps session, or performed when working any other upper-body muscle groups. Keep the repetitions in the eight to 15 per set range and use strict form; as an isolation exercise, going too heavy and using low reps can place excess strain on your wrist and elbow joints. To progressively become stronger, perform three sets of 12 in week one, four sets of 10 in week two and five sets of eight in week three. Take a week off, then go back to three sets of 12, but aim to use a little more weight than before.