Not the person you are responding to but you might find this article interesting: https://www.outsideonline.com/2336111/defining-upper-limits-fitness https://ww

Not the person you are responding to but you might find this article interesting: https://www.outsideonline.com/2336111/defining-upper-limits-fitness https://www.outsideonline.com/2336111/defining-upper-limits-... I’m not sure what role testosterone plays in ultra endurance sports but there are other considerations besides only testosterone.