Originally Posted by _craze
...the first ball he hits is a half-volley (ball hits the court and you finesse it back in the court), not a volley. The second shot is a classic volley, no topspin there.
So if what you're doing is a half-volley, then fine...that's one more tool in the toolbox, and everybody who comes anywhere near the net needs a half-volley.
The Williams sisters, among others, do use a swing volley when the ball is up high, and it's basically a topspin groundstroke in stroke path. Doesn't work for me, or most volleyers, but if that's what you're doing and it works, fine. I don't see how anybody can hit a true topspin volley against a low ball, so I'd like a video of what you're doing, too...