Originally Posted by sureshs
What causes the oblong shape? I had an interesting discussion with a guy during the Nadal practice. Top spin causes the ball to go down due to the Magnus effect - more pressure (less air speed) on the top than the bottom. Is this the same reason for the compression of the ball vertically giving rise to the oblong shape.
This guy also went on and on about how he asked Dennis Ralston about modern pro forehands and was told that the secret was a wrist bend and then a movement of the last two fingers (the ones closer to the ground) which provided the extra force into the ball. Don't know about that.
regular ol' centrifugal force. the 12 and 6 areas of the ball are travelling faster than 3-9 areas. so after a certain threshold is reached the pull of the 6-12 is strong enough to stretch the ball.
i wonder what that guy meant by the 2 fingers.