Jy. You have to know its not my instruction. I'm just trying it. And yes i know the racket does not go backwards as the ball comes at you. I just tried the techniqiue. It feels different and i dont think the pros do it or not. You cant tell from video because even when I watch myself in a mirror the swing looks the same but it feels different. Like I said try it and it feels different. The sound is different. If its right or wrong the racket head moved faster. Thats all. Not endorsing anyone. And anyone can perform the experiment for themselves. Go to you racket bag and just do it.