White, Caucasian men tend to dominate strongman competitions.
Blacks tend to dominate boxing (I can only think of Tyson Fury and Klitschko) and sprint events.
Gymnastics is starting to have equal representation at the highest level.
MMA does tend to be predominately white.
A strange mix here.
I mean there may be something to that but one also has to think that culture and expectations play into it. We know that athletes come in all colors, races and ethnic groups (also sexes, genders etc).
However, if one considers African American's in the US than many are going to be geared towards basketball or football. Not so much hockey. Does not mean it is a zero sum game but that does slant things.