Before there was Lululemon, before Nike Women and Lucy and Title Nine — both the apparel company and the actual law — there was Roberta “Bobbi” Gibb in a one-piece bathing suit, her brother’s Bermuda shorts, and little boys’ running shoes. Gibb, the first woman to run the Boston Marathon back in 1966, didn’t have the luxury of choosing which sports bra or capri leggings to wear for her historic 26.2 mile run. Women’s athletic wear didn’t exist yet.

It would be 10 more years until Nike manufactured a running shoe specifically for women, and another year after that before the introduction of the “jockbra,” the precursor to the modern day sports bra.

Gibb ran that red-letter marathon illegally, as women were banned from participating due to concerns that a woman’s fragile body couldn’t withstand the demands of distance running (reminder: this was only 50 years ago. Whoa!). “I hadn’t intended to make a feminist statement,” said Gibb. “I was running against the distance [not the men] and I was measuring myself with my own potential.”

If you’re an athleisure aficionado like me, I think we owe a collective debt of gratitude to Bobbi Gibb. Had she not run Boston in 1966, Kathrine Switzer likely wouldn’t have run the race the following year, and the eight female runners who crossed the finish line as legal participants when the female ban was lifted in 1972 likely wouldn’t have shown up either. But they did. And women across the country took note. One mile at a time, women’s running became mainstream.

So Nike took note. And the three women who invented that “jockbra” in 1977 realized that maybe they weren’t the only ones who were in the market for women’s activewear. They were right, of course, and the market officially exploded in 1998 when Lululemon, Athleta, and Sweaty Betty all hit the scene with the same aim: To create active wear for women that is both functional and fashionable.

One mile at a time, women’s running became mainstream.

Why does all of this matter? Are cute yoga pants really cause for a historical retrospective? Maybe, but that’s not what I see as the moral of this story. What I see is that the world was not ready for Bobbi Gibb, but she ran her race anyway. Without the right shoes, the right clothes, the right support, or the right social constructs, she followed her passion. “I was not a competitive runner, but I felt connected to the earth and air and sky,” she says of why she ran.

And the world caught up with her. Eventually. I ran my first marathon a few months ago in Big Sur, California, amongst a crowd of runners comprised of 51% women. I wore high-tech running leggings from Lucy, an elaborate and stylish sports bra from Victoria’s Secret, and Asics shoes that a running store professional selected just for me. And I thought of Bobbi Gibb while I waited at the start line, feeling nervous and not ready. I thought about how “not ready” isn’t a valid excuse, and how different that scene would have looked if she had acquiesced to a world that wasn’t ready.

The world is rarely ready for the women who make history. No matter, they’ll catch on eventually. And if you need a reminder, just look in your activewear drawer and say a silent thank you to Bobbi Gibb and her black bathing suit.

Anna is a freelance writer and copywriter living in Sacramento, CA with her husband and two young sons. She believes that stories bring people together, sweat cures almost everything, and time spent outside is never wasted. You can catch up with her on Instagram, Facebook, Twitter, and her personal website.

www.annaquinlan.net/