I make no claim at all of my knowing what I'm talking about here, but I did watch Cynthia Guffey demonstrate this in her "Darts" class at ETA, and to the best of my recollection, this is what she said and did to attest for the fact that her arms -- even older than mine -- look great!
You are to use TWO pound weights (these are only one pound), and you are to do it FAST for TWO minutes.
Hope you will try it.
If you had problems viewing it, please try again. I think I fixed it.