Hi, I'm a 50 year old player that hits with power, I've been using a Wilson Kblade 98 at 11.5 ozs. I've tried to use a heavier racquet but have not been successful as my arm just tires so easily and not being the best of shape I just get fatigued. I have so wanted to play with a heavier racquet for all its benifits so I started a new and pretty easy training regime. Simply I started to swing 10 pound barbells as though it were a racquet, doing forehands, backhands, volleys and serves. It was very tough at first, for the first few days, but after that it became pretty easy. I can swing 10 lb barbells at 60 reps now for each motion. It has done tremendous for my arm strength, endurance and racquet head speed. I really wish I had done this before, though I do notice my right side getting alot stronger than my left, so I've been including my left side also as of late. I've been able to add alot of weight to my racquet, 1 ounce since I started. In fact my racquet right now is 12.5, 4 points head light. The fact that it is only 4 points head light is very significant in that I have so much head weight into the ball now that, the ball is just crushed. Its quite remarkable actually how much and how heavy the ball is. As an experiment to see how heavy it would be at about 8 points head light, the racquet would be well over 13 ounces. I would say it helped out the serve and overheads the most. they are heavy heavy shots. The backhand is very solid and so is the volley's. My strongest part of my game was my fore hand and now its just a ripper. Anyway, I kinda revealed to my friends what I've been doing and now, everyone is doing it. It improves the game that much. Its a easy way to help develop your strength and improve your game. You should try it see what ya think, I can't be any happier with the results.