My opinion is shorter backswings are MUCH better. I think Agassi ground strokes or Federer's FH with compact backswings and full WW follow-thrus have inherit advantages. At higher levels, a full backswing will be difficult as you will not have as much time and timing the hit will be more difficult. Also, shorter swings have less moving parts which equates to less things to go wrong in my view.
But, Soderling had massive swings and did well with them. So, it can work either way but I strong feel compact backswings are the way to go. Some WTA players also have longer backswings like Wozniacki.
My rule of thumb is the entire swing should be in front of your shoulders - you pivot the shoulder to the side as part of the prep and from there, the hand and racket head should start entirely in front of you chest/shoulders. The racket head should never go so far back that your opponent can see it sticking out from behind you back.
Last edited by TennisCJC; 09-27-2012 at 06:55 AM.