As a human biology major, she scrutinized the lessons of every class through the lens of an elite athlete. When she studied primate behavior, she contemplated human competition, noting how bonobos were drawn to the teamwork she yearned for. In osteology, she considered how her bones connected so she could optimize her stride. Studying psychology, she taught herself to recognize adrenaline as false fear, and to mitigate the power of pain so that she could tolerate more.

Image Lauren Fleshman winning the women’s 5,000 meters at the N.C.A.A. track and field championships in 2003 while at Stanford. Credit... Steve Yeater/Associated Press

By the time Fleshman graduated from Stanford in 2003, she was an all-American 15 times over 12 straight seasons — having finally earned the scholarship she had once been denied — and a five-time N.C.A.A. champion.

But she also realized that throughout her career, all of her athletic role models had been men. She was particularly interested in the Stanford men’s running team, at that time a legendary cohesive body known as the Machine, which regularly outperformed the similarly talented women’s team.

“They had a tradition and history and richness of accountability that they had created for one another, and we didn’t have that,” she said. “I was fascinated. I decided part of it had to do with the effects of puberty on men — they get more muscular and powerful — whereas women get more body fat and estrogen. Their whole hormonal profile gets optimized for childbearing, whether you want to or not. We were terrified of it. So we weren’t working together, and we were weaker.”

As Stanford’s captain, Fleshman pushed for camaraderie, and when she remained for a year after graduation to work as an assistant coach, the women finally won a national championship.

Navigating the field of professional running proved more difficult.

Sponsored by Nike, Fleshman won her first national championship in the 5,000 meters in 2006. But she was troubled by her role in the company; in Nike’s ad campaigns, she noticed, male athletes figured prominently, while the marketing materials directed at women featured fashion models. Restless one night, she emailed Nike’s chief executive, Mark Parker, asking if she could meet with him. Parker invited her to his office the next day.