brady viles sucks taint
Emile Heskey
Stefka Kostadinova
Michael Phelps is the most decorated olympian of all time.
tupac shakur
Pele
The 50m is the shortest, but not necessarily the "easiest". If an athlete is truly competing to the best of his ability, all events are difficult in the sense that the athlete is pushing himself to his limits. With the 50m, you are running for the shortest amount of time, but at the fastest pace.
Don Bradman.
Tiger Woods
ddd
Decathlon.
The amount of time that an athlete trains varies greatly from athlete to athlete. Some train for up to 30 years depending on the sport and some barely train at all
This answer may vary depending on what you define as "successful," but generally, Michael Jordan is usually considered the most famous American athlete of his time.