Incline Cable Overhead Extension
There are a couple of reasons to place your arms at a 45 degree angle during the skullcrusher. One is to induce constant tension on the triceps from start to finish. When you draw your arms back slightly, your triceps are called upon throughout with no real chance of resting during the rep or set. The second reason is that the farther back your arms approach an overhead position, even when you’re lying down, the more you engage the meaty, long head of the triceps. The incline cable overhead extension puts your arms in an almost an identical position as the 45 degree skullcrusher.
Single-Arm 45 Degree Dumbbell Skullcrusher
If you don’t have an incline bench or an EZ-bar, you can still target the long head with a dumbbell by angling your arm back above your head slightly. In fact, even though you may be able to do both arms simultaneously, the benefit of using a dumbbell is that you can use your free arm to provide a spot if you want to train past failure. Help just enough to squeeze out a few more reps. At the end of the set you can sit up and rest for 30 seconds before hitting the opposite arm. It is advisable to start these exercises with a different arm from one workout to the next so that each has the benefit of beginning first when you’re freshest.