Originally Posted by Limpinhitter
Borg and Lendl's balls are ranging from 3-6 feet over the net. Fed and Djokovic's balls are about the same. You can't tell what the clearance is from that perspective, but, I've seen them live, and they get a lot of clearance over the net.
I haven't seen Fed or Djokovic play a real match from court level, but I have watched both play practice sets from court level on the hard courts at Indian Wells. Neither was hitting an average rally ball between 3 to 6 feet over the net. The shots 6 feet over the net or close to that were almost always defensive shots designed to get the player back in the point. I'd say the usually rally ball has less than 3 feet of net clearance.
Last week I was out at Indian Wells watching again (didn't see either Fed or Djok on the practice courts). However, I watched a number of professional players at court level on the outer courts and in practice sets. Low net clearance was standard. The average rally ball in a match was hit between the net cord to 3' over the net, with probably as many in the lower half as in the upper half.
The players do hit higher heavier topspin balls, but those are definitely not the standard balls in my experience watching hard court tennis.