Lately, I've been thinking a lot about genetic restrictions and the impact that has my practice routines.
I know Thomas Lang explains "Creative Coordination" that he doesn't believe in "talent" . . . but that hard work will pay off for just about anybody. That's why he's reached such a level - through focused practice for many years.
However, people do have (at least) physical restrictions which prevent them from doing certain things. Or, it makes it a lot harder to master something, because progress is much slower than it can be for other people.