This Book Reveals Some Shocking Truths About the History of Fitness Culture

Fitness has made women a societal force to be reckoned with, says Danielle Friedman, author of Let's Get Physical: How Women Discovered Exercise and Reshaped the World. It has also changed lives on almost every level: The physical empowerment it brings can lead to more happiness, confidence, and fulfillment. Here, Friedman talks about harnessing that power. (More: Black Trainers and Fitness Pros to Follow and Support)

Shape: Your book establishes a fact most don't realize — that exercise is a relatively new phenomenon for women. Why did it take so long to catch on?

Friedman: Until fairly recently, women didn't have the freedom to exercise. We transformed from a culture where sweating was unladylike, women were afraid of muscle, and girls grew up believing vigorous exercise would cause their uterus to fall out, to the world we live in today, where women's fitness is ubiquitous. I wanted to explore how we got here. What I found was that there was a perfect storm of social and cultural shifts that contributed to women being more active: The rise of the women's movement, a growing body of research suggesting that everyone could benefit from exercise, including women, and women entering the workplace in greater numbers than ever before, which, for many, meant they had money to spend on exercise classes.

Shape: How did getting physically stronger make women feel more powerful?

Friedman: What I heard, again and again, is that as they developed physical strength and trust in their bodies, women suddenly felt more capable of navigating life's challenges. For instance, fitness icon Kathy Smith told me about students who would come up to her after aerobics classes and say, "I finally asked my boss for a raise," or "I told my husband I want to go back to work." And so many women reported the same thing. The benefits of feeling physically strong can extend to mental and emotional health, too. (

Think about this: In mid-20th century America, men were told from a very early age to be physical and become strong, and women were told to fear their bodies. As that began to change, which I believe was largely thanks to the rise of women's fitness, the social balance started to shift. The scope and impact of women learning to connect with their bodies has been huge.

Shape: The women you spoke to said working out made them feel young. Has exercise changed the way age is perceived?

Friedman: There's a lot of focus on exercise for longevity from a clinical medical standpoint. But perhaps the real secret lies in the ways that exercise helps women feel fully present and able to use their bodies and live their lives the way they want to into their seventies, and eighties, and beyond. There's the idea that 50 is the new 30, and so on. I think age has a very different connotation now because of our activity level. (More: How to Stay Young and Increase Your Longevity)

Shape: So then, how can we motivate even more women to embrace exercise?

Friedman: In our culture, fitness has been sold as this all-consuming lifestyle that requires a fancy wardrobe and significant amounts of money and time. I experienced this myself — I didn't feel like I had enough time to run, even though I love running. But now, on a day where I don't have the 45 minutes to go out for a run, instead of just sitting at my desk and doing nothing, I go for a 30-minute walk. Maybe that's not exercise in the way I was conditioned to believe in because it's not rigorous, but I feel so much better afterward. I think we need to expand our understanding of what fitness is. If we start focusing on moving in ways that feel good, that's one way to get more people involved.

Shape: What was the most surprising thing you learned while writing the book?

Friedman: That the sports bra wasn't invented until the 1970s. And like many innovations in women's fitness, necessity was the mother of invention. For the first time, women were moving in numbers that were great enough to inspire the idea and turn it into a wardrobe staple. Before that, some women would wear two bras, and others would wear no bra at all. The inventors of the sports bra — three women, of course — were very savvy about marketing it. The lingerie market was notoriously difficult to break into, so they sold it through sporting goods stores. But they had to package it in a way that was socially acceptable and discreet. They came up with the idea of categorizing it as a piece of athletic equipment. (More: The 12 Best Sports Bras for Running, According to Customer Reviews)

And then there's the story behind Lycra. It was invented to create girdles, but as women started ditching their girdles, it became used to make leotards. Lycra completely transformed from being a fiber of repression to one of liberation. That just blew my mind.

Danielle Friedman is an award-winning journalist whose writing has appeared in such publications as The New York Times and Vogue.