If you have had it done before, then you know that it's more then a needle in the surface of your skin. The Dr. will flick the needle in your skin, then he will twist it until your muscle begins to twitch, some Dr's will then attach electrical leads to the needles and begin a muscle stimulating session for about a half hour, it is a ittle weird i the begining because you body is jumping, but you gte used to it and the injury feels better afterwards.
like the old adage: Don’t knock it until you’ve tried it!