Don't go swimming with sharks. Creatine does work but I personally have experienced no benefits beyond the "loading" phase. I also didn't experience any benefit on subsequent loading phases. It's also not great for endurance and since we're primarily concerned about tennis here (or squash, racquetball, trailrunning, skiing for me), it has limited benefit. Bodybuilding is a world I have ZERO interest in. Regardless (or irregardless, per r2's wishes), good luck with your diet/exercise plans.