You can keep the arms bent the whole time pretty much. And that's what I do. There is always a bend in the elbow. Just pick up the bell with the arms a tad bent, then lower behind the head. Keep your hips OFF The bench. The only thing that should be on the bench is your upperback really.
Like so.
http://www.kcount.com/webIQ/Img/back_dumbbell_pullover_end.jpg
Now she's got the idea there, but what I do is let the elbows drop even just a hair lower than that. Then just do a pullover/extension type movement. It's not a lockout. Really it's just a regular ol bent arm dumbbell pullover, however most do these with straighter arms for more lat effect but once you bend the arms the triceps are going to fire like mad.
Check out Nassers tri's here and tell me they aren't screaming....
http://www.giantpt.com/BodyPerfect/Afbeeldingen/Pullover01.jpg
Skip LaCour
http://www.skiplacour.com/All_Images/skip_pullover_10-12-98.jpg
You can clearly see the tris contracting big time, so I never understand how some say your tri's aren't being hit with these. It's impossible for them not to be.
What you are NOT after is this.....
http://www.darkworldgraphics.com/workout/c_pullovers2t.jpg
Frank here is doing more of the straight arm version. Again, anyone I get to do the bent arm type gets more sore in their tri's than anything else they do.
Here we go! Here is exactly what I am talking about. Although he's using a bar, the movement is perfect. The only thing that happens different is that when you use a dumbbell instead of the bar, it makes you do more of an extension at the top, because otherwise the dumbbell will hit you in the head. Where as with the bar, you can use it more for the lats.
http://www.exrx.net/WeightExercises/LatissimusDorsi/BBBentArmPullover.html
have fun
