You know the feeling you get when jammed inside, feels like you hand is bruised. This happens to my DD when hitting off a machine. Makes no difference if she squares it up or not.. hitting off a machine hurts her hand. She's not one to complain and would play on one leg, so I am wondering what she's doing wrong. FYI, the balls are regulation. I know this is a weird topic that doesn't make a lot of sense.. but I am just tossing it out there, :0