I once heard that if you ball your hand into a fist, and punch the palm of your other hand, that depending on how loud it is, you can tell if you are hitting hard or not. I don't think this is true. After a workout, I can punch my palm and it will sound loud, but most of the time it won't sound that loud, whereas all the kids and school can do it and it will sound very loud. Anyonek know anything about this?