How to perform skullcrushers Target and strengthen your arms with skullcrushers.The Move:SkullcrushersWhy: Skullcrushers are a great exercise to superset with other tricep exercises and work well as the second exercise because you can go fairly heavy with weight.How: Lie down on bench and bring weight up. Keep arms straight up to ensure you’re working against gravity. Only bend your elbows. Avoid allowing upper arms to move. If they do, allow some of the load to your shoulders.