Hi there,I owned a Yonex Muscle Power 19 light racket and with a BG-6 string on it, After a smash in game, i need to readjusting my string to everytime, please guide me waht can i do for the next, and i prefer to change my string since is quite old ( 3 years) didn't even change the string, and for the view and reply if you willing to tell me what to do next. thanks