Do you have any evidence for that ? I know for a fact that Federer doesn't (he said it himself in an interview), and all the videos of top pros I have seen like Nadal or Djokovic seem to show that they don't either. Citation needed.
Btw 2nd serve and first serve are different shots, so it's not surprising that players change grips between those, that's not what I'm talking about.
Same for return or serve, even I use a lightly different grip there especially for my backhand.
As for the fact that a good amateur can learn several grips for his forehand ? Sure, obviously even. I'm not even a good amateur and I can hit a variety of Forehands. I can hit one handed or 2 handed backhands too. The question is, are there more pros to switching grips to get more spin or drive on specific shots than there are cons ? It would require twice as many hours of play to get to the same level on each grip, maybe more considering your muscle memory might get confused from time to time, so imo it is time better spent elsewhere.
Again, it is very rare even among pros.
Calling BS on that Fed interview claim. I have seen an interview where Roger was asked what Fh grip he uses. He indicated that HE REALLY DOES NOT KNOW.
This is Not unusual. Many pros are consciously unaware of how they grip or execute various shots. They are performing much of their mechanics on an unconscious level. Do you know the
four levels of competence? Elite athletes, for the most part, are operating at the 4th level. Because of this, many top players do not make good coaches. At least, until they stop and actually analyze exactly what they are automatically subconsciously) doing. The 4 levels:
1 - Unconscious Incompetence
2 - Conscious Incompetence
2 - Conscious Competence
2 - Unconscious Competence
When asked about how he serves, Novak Djoko got some of the details wrong. Anyone who has studied his serve closely could see this. Novak was merely parroting what he heard his coaches had said to him (as a junior player) when he was developing his serve and his other strokes.
Many pro players recommend using the same toss for all serves. They claim that this is how they do it. However, Hawk-Eye data and slow-motion HD video reveals that this is false. These players often employ a significantly different toss for the 1st serve than the 2nd.
In his Udemy course, Andre Agassi insisted that he used a standard Eastern grip on his Fh. Vids & pics reveal that he did use an EFh grip... Sometimes. Other vids & pics of AA, in his early years as well as his later years, show that he often used a grip that was much closer to a std SW, esp on high shots.
If elite level cannot accurately tell you exactly how they perform strokes, there is a very good chance that they are unaware of subtle grip changes that they employ. Or grip changes that are not so subtle.
Try perusing this forum. Over the past 2 decades (almost), a lot of video & photographic evidence shows many of the differences I've mentioned.
For example Will Hamilton (FYB) and Ian Westerman (Essential Tennis) "prove" that Roger used a standard Eastern Fh grip. However, Tennis Mag, Tennis Channel and various other sources show him using something different.