LOL that is the infamous MIT video which caused a lot of embarrassment in a famous deleted thread. Push the ball, slap the ball, and throw it over the net? Really? This is one of the few videos which actually shows the technique being taught and practiced - as you can see, there is no power in the shots.
Instead of answering this, you will find a lot of videos of Fed and Nadal thrown at you, as if they have something to do with this.