I think many of us like to hit groudstrokes like or remotely close to Fed's or Nadal's at some point. A shot like that would look beautiful when it goes over with topspin and speed. I dont' mean one can easily achieve Fed or Nadal's level, but any healthy adult can crank a pretty hard shot, but most people's problem is the shot will likely be out! I see this problem as some sort of NOT having a definitive knowledge of the mechanic of performing such a shot. I think I had it but I really don't because I just don't know where to emphasize and train on. Most of my "hard" shots are just result of random luck. That's my problem. It's frustrating. What's yours?