A coach said that my racquet is too heavy and after 2-3 years I will have problems with my arm. I wouldn’t care, but my father heard him and you know... My racquet is a 384g PS85. I've used with it for 2 years and I’ve never had injuries. I told them that Sampras played with a 400g, but... with no effect. Considering my textbook technique and that my racquet feels maneuverable at the net, should I change the weight? And more importantly: what should I tell my "health consultants"?