There are certain tennis strokes that adults can't learn. For instance, adults can't learn to hit a "kick" serve that has a lot of topspin. I think part of the problem is that the kick serve requires counterintuitively hitting the ball to the sky and letting gravity and spin pull it down to earth. Adults can't handle the idea of hitting up, it just seems wrong. I learned kick serves as a kid and it's like riding a bi…
There are certain tennis strokes that adults can't learn. For instance, adults can't learn to hit a "kick" serve that has a lot of topspin. Do you have anything to back this claim? I don't believe this at all. The plasticity changes as we get older, but the human brains does not lose the ability to learn things, counter intuitive or not.
Perhaps not lose entirely, but certainly age can dramatically reduce the ability to learn certain things. This (rather long) article goes into detail:
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2947444/
The section marked "Language Exhibits a “Critical Period” for Learning" is maybe the most relevant.
However, the article was written in 2010, and may be out of date. Understanding the brain's mechanisms and plasticity has advanced significantly over the last few years.