Some lifters prefer this to the the regular skullcrusher because the triceps must work harder and tension is maintained.
You must keep your elbows in at your sides throughout the set and dont let them move forward or back.
Do not lock your elbows out at the top of the movement as this takes tension off the triceps.
Instructions
This exercise is a variation of the lying tricep extension (or skullcrusher). Sit on the end of a flat bench width a barbell on your thighs.
Grip the barbell with an overhand (Palms facing down) with your hands about shoulder width apart.
Bring the bar up to your chest and lay down on your back.
Extend your arms straight up above your chest.
Keeping your arms straight move the bar back to the position shown in the video above.
Keeping your elbows fixed in place and not pointing out, slowly lower the bar until it is almost touching the top of your head or bench behind your head.
Pause, and then slowly extend your arms back to the starting position.
Do not lock your elbows out, and then repeat for desired reps.