Ethnic background and spints
Most of the world record holders for the 100 m sprint, especially for men, have traditionally been African American in Origin. Jesse Owens was the first high profile African American athlete in the 1936 Olympics
The world record holder for 100 m sprint for women is Usmain Bolt from Jamaica and the earlier record holders like Carl lewis are also African American in their ethnic background. While training plays a role in the success of athletes, it appears that genetic factors also determine whether an athlete will be successful in the sprints, especially for world class events.
In contrasts there are relative few Asians who have won world level sprint events of 100 m, 200 m and 400 m or are ranked in the top 10 in the world.