Get up get off (alternate version)

I know I'm not it's, uh, target demographic, but I love Men's Health magazine.

Nelly's on the cover this month with the inspirational quote 'A great body is a gift to yourself.' Well, yes, but your body is also a gift for us chicks, dear Nelly.

My triceps are sore today because yesterday I followed the 'Build The Perfect Triceps' pull-out poster. Here's the move I like (cuz I'm guessing you could use it too):
While lying on a bench, 'hold a set of light dumbells (I did 8 lbs but could only do 3 sets of 10, so I'm thinking lower weight would be better--for me at least) overhead with your arms straight and your palms facing each other. Keeping your upper arms stationary, slowly lower the weights toward your shoulders until they reach the sides of your head. Pause, then slowly press the weights back up, keeping your elbows locked.'

Sounds so simple, yet is so hard, hard, hard.