Originally Posted by Cheetah
you actually get greater swing speed if you dont look at the ball at contact.
This certainly appeared to be the case for Roddick. His eyes appear to be on the ball when his arm reaches full extension (racket in the "big L" position). however he quickly pulls his eyes/head down so that at contact he appears to be looking at the receiver.
Contrast this with Sampras
. These guys keep their eyes on the ball longer/later. From the slow-mo videos that I've seen of these two, their eyes appear to be on the ball pretty close to contact. From repeated viewing of a number of videos, it is conceivable that their eyes might be on the ball at contact but it is difficult to determine, with absolute certainty, if their eyes are really still on the ball.
Because the hitting shoulder comes over the top (shoulder-over-shoulder cartwheel action), the head must move off to the side a bit. The head and neck also rotates somewhat to accommodate the shoulder. However, it does appear that Roger and Pete still watch the ball out of the corner of their eyes
even tho' the head had moved/rotated.
Bottem line: I would say that Roger & Pete might very well be looking at the ball at contact. Even if this is not so, it is apparent that their eyes are still on the ball very close to contact unlike Andy (Roddick) and others.