Everyone focuses on racket stiffness and poly strings causing arm problems, which is very true. Has anyone else noticed that some types of balls can be tough on someone with elbow or wrist problems? I deal with both, so it is always a balancing act to not create too much damage. I just about can't play with Dunlop or Wilson US Open balls. Dunlop balls are very hard, feels like I am hitting rocks. The Wilson US Open ball is heavier and slower than the standard Wilson or Penn heavy duty championship ball. I did drills with my son last night using the local university team's standard practice US Open balls. I felt like I was hitting balls that were filled with water. Just heavier and slower, with alot more stress on my wrist. Anyone else notice this before? I know I've walked on the court where someone else provided the balls, and after 3 shots realized we were hitting Dunlop balls due to their hardness. Seems like at least in my case, the ball type is as big a factor in bringing out elbow and wrist issues as racket and string type.