On Thursday, August 31, 2017 at 3:40:23 PM UTC-7, JQ wrote:

Back in the day when I was a runner on the USA national scene, I never
wore women's undies nor anyone that I knew. Now some did wear women's
leggings during the winter and freezing temps for races, as far as I
know we all wore men's briefs. My day was back in the 70's, I can't say
post 70's as I was no longer able to run.

And you didn't want to socialize with men that wore women's undies.