Originally Posted by sureshs
I don't think they can. All they seem to do is to manage to get the racket face perpendicular to the ball trajectory at impact and control the curvature to some extent, so as to meet the trajectory smoothly (as I had said before). You seem to think of linear as parallel to the sidelines. I think of it more as a measure of local curvature of the arc at impact (what you would know as reciprocal of the second derivative).
It is absolutely obvious that in order to hit through 5 bolls the racquet should move along a straight line at least 10’’ with stable racquet face orientation. “Piston stroke” can provide this, but you don’t want to utilize it because it is slow motion. Then, you should think about approximation of the straight line.
Radius of Osculating circle of the straight line is infinity. Thus, if you use rotational motion only, you have to increase radius of rotation as much as possible. From this point of view, straight arm FH is probably the best, because that creates maximum radius. However, most pros use bend elbow FH. So, they don’t care about hitting through.
If you know some different but particular way to “control the curvature to some extent, so as to meet the trajectory smoothly”, just let me know please.