Pedagogy is not reality. In fact, many of the things he is expressing are many of the things I feel when I play my own topspin. Are they literally true? Probably not. But are they communicating his technique how he thinks about and feels it so that someone else can replicate it? I would argue yes. It is okay if you disagree. But a common issue with communication is when someone listening tries to take someone communicating so literally that they fail to understand their intent is to teach, not to get a PHD in Physics.I just looked at the video. This is a great video. But part of it is ridiculous and absurb.
He is great at top spin but I have a couple comments:
there are only two types of top spins: one is higher arc where you use almost mostly the topsheet to grip the ball so the spin has a high arc to it and a bit slow (tacky Chinese rubber is very good at doing that). two is the hitting through the ball while snap your arm and wrist upward like a sling so you engage the sponge; in that case the topspin has a more linear projectory.
That the first and the third top spin he was referring to.
there is no "second" topspin he was referring to. He was basically driving the ball/smashing the ball in that "second" topspin demonstration. I don't consider that topspin at all. I consider that a drive or smash that you put a little bit of top spin to make sure the ball gets over the net.
With the first type of topspin, where you lightly brush the ball with the top sheet only, it is much much easier to be done using a Chinese rubber.
With the second type of topsin, where you engage the rubber and the top sheet at the same time, that's what all pro's do. That's why their topspin is so powerful when you are trying to block it because you have to deal with two sources of energy that the opponent puts onto the ball: a) the forward momentum and b) the rotational energy.
Finally yeah, in order to do top spin well, you have to be completely relaxed and then burst and sling your body, legs/waist/forehand/wrist in one single moment when you contact the ball. That is the only way to get a quality top spin. You cannot be stiff and just "hit/brush" the ball hard. Instead you need to use your body like a sling.
Also once you commit to an angle for your blade, you commit to that angle; there should be no going back. Balls are coming at you fast. Why would you change your bat angle in the middle of your motion.
The instructor is saying, to make your topspin better, don't forget to change the angle in the middle of it and "cover" the ball so you have a longer dwell time. For 99% of us mere mortals out there, that is not really possible and really not reasonable. People are using Super Viscaria with Dignics on both sides. You really think there is any dwell time for you to "cover" the ball and let the ball "stay on the blade" longer? no, the ball was already slung out of the blade by then. Plus, like I said, when you do a topspin (whether the incoming ball has topspin, no spin or backspin), when you mentally assess the type and the amount of incoming spin, you have to adjust your bat angle and be 100% committed to it. The ball will be there in a split second (or less!). Changing your bat angle in the middle of your motion "to cover the ball" is the worst thing you can do your development as a player.
So please, try to understand and empathize with what he is saying (I am assuming you have hit sufficiently high level forehands to critique him insightfully). What he is saying is that he pronates his salute at contact (or possibly throughout the stroke) and swings through a curved path that shapes the ball. People who have this technique will know what he is saying. Unfortunately, people who don't and focus on how he expresses himself will miss the point entirely. And this is not a bad thing as long as one realizes that in teaching and learning, one should never assume that the way one communicates it is the only way others can understand it. Let's just say that I am convinced based on my experience with the stroke that his instruction will work for some people even if it doesnt work for you.