Are you sure about that? That goes completely against everything I've seen, and I come from an area known for high performance athletes. So much so that I used to eat lunch in highschool with someone who would go on to compete in the Olympics.
I associate sports, and especially their pursuit at a high level, with a high socio-economic background. Only the rich can afford the gym memberships, travel, gear(heh), time and energy to pursue sports. Every single Millennial I know who is serious about sports came from an upper-middle class or better background. 0 exceptions. I laugh hard about sports scholarships being really just a kickback for the rich. Every person who got one in my highschool class came from a family rich enough to put them through multiple camps a year, private trainers, fancy equipment. They were going to college either way.
Meanwhile, I like running and lifting weights and almost every older person in my blue collar network thinks it's stupid and I should work outside if I want to get exercise.