Sports or studies psychology:
In sports specially, you will find a person who plays all day but doesn't become a champion, and remains an average sportsperson.
On the other hand, somebody else who plays less and less becomes a champ almost overnight.
You will find winners at a very young age, or very brilliant students in schools and colleges.
It may be all about psychology.
There are so many books on how to become a great sportsman, or how to do well in studies.
It's also about a single minded dedication in a particular field.