One of the ladies taking lessons with me is having some issues with a developing tennis elbow with a Wilson Hammer 6.3. Her therapist told her it was because her racket was too old (more than 5 years old) which i personally think is not an issue at all. However, i feel like the 6.3 is on the stiff side just from hitting a couple of balls with it. It is strung with a soft multi. Any "modern" suggestions to replace her trusty Hamer 6.3? I thank you in her name.