You can also see it here with a medicine ball: http://www.exrx.net/WeightExercises/Oth ... hupMB.html
I remember reading that some people will do this with 1 or both hands on a dumbbell so that when they lift the hand in the air at the end of the repetition, they are lifting the dumbbell up.
I was wondering, does anyone ever do this motion without doing the push up part, where you just twist your torso and raise the dumbbell up? It seems like a good back exercise. Basically like it would hit the same muscles as doing a reverse fly. Not just for the free-moving arm, but also for the base arm because it is like a closed-chain movement where the torso is being lifted up on top of the arm, whereas the free arm lifting the dumbbell is open chain.
It makes me wonder, it'd get pretty hard with higher weights, not just due to the lateral raise, but you would be shifting your weight more and more over the base arm the heavier the weight got and the straighter you kept the arms.