I'd find a new stringer because yours is delusional.
I'll go ahead and elaborate...any stringer who would make such a comment either has zero perspective, innate bias, or just likes to hear himself talk and/or argue.
Babolat rackets are used by the masses (Pure and Aeropro drives) typically strung too tight with a poly string and the number of people who get on this message board reporting arm problems are very likely out of proportion to the population who actually has arm problems secondary to a Babolat racket. People have perpetuated the myth that Babolat rackets are automatic arm killers. I know people from 12-80 playing with pure drives with ZERO issues. We have had people on here say Babolats cause arm problems, yet they have never hit with one. Let it go! A prestige can cause arm problems just as easily as a Babolat if you have poor technique. I'd rather swing an 11 ounce racket around improperly than a 12.2 ounce racket. I'd venture to say your risk of injury is lower. If people really think that 1 ounce in weight makes a big difference in whether or not you will get tennis elbow, I'll go ahead and say probably not. If you hit a one handed backhand, are out of shape, and make contact behind the ideal point, thereby adding stress to the common extensor tendon origin at the lateral epicondyle, you are probably going to get tennis elbow with any racket out there.
If you use a racket with a stiffness of 70+ with tight poly strings, you are probably more likely to experience discomfort (wrist, elbow, shoulder) than using a prince o3 tour with an RA of 52 with natural gut at 44 pounds, but you may also be less likely to injure your rotator cuff muscles muscling a heavier racket trying to hit a 120 mph serve (which odds are almost no one on this forum can hit). Life and injury are all about trade offs, and I can assure you playing with a light stiff Babolat has pluses and minuses in the health department as well as in the tennis performance department.
I think tight poly strings are more dangerous than a stiff frame. Pure Drives are pretty comfortable with a synthetic gut...which 95+% of rec players should be using. The problem lies in people wanting to use what the pros use. I've seen plenty of people with problems trying to muscle around a k six one 90 with added lead as 3.5 players.
Let's also admit that many people don't want to use a pure drive because of their popularity...saying they cause arm problems is a more noble excuse in some people's eyes for staying away.
I'm not as strong as Nadal (in a tennis sense of muscular), but I have never had any problems with a Babolat frame and I've tried many. To say they aren't good rackets is asinine. To say they have to be played at 44lbs is even stupider.
I will now step off my soap box.
