I just got my powerball yesterday for Christmas. Today my hand feels like it's dropping off and I have already spilt two bowls of cereal  

 (which I would never normally do)! Mom is not happy!
Anyway, I think it could possibly help for XCM but it depends exactly what sort of thing you do, and how extra strength would help you (?). I don't know. 
They are certainly addictive though and pretty fun too! 
*goes and plays* *wrist hurts*