I have checked out all the 'useful links' threads but I couldn't find out whether the string pattern on your racquet makes any difference in the 'heaviness' of the ball you hit. My 5.0 level friend who uses an old i.prestige MP constantly gives me trouble with heavy balls, both at the net and at the baseline. He broke his strings the other day and I let him borrow my 6.1s. I found that his balls were easier to hit though he had not changed his swingstyle or path or his body positioning during the stroke. Is it just a case of him not being used to the racquet or does string pattern influence how heavy you hit the ball?