Among the most important advances in sports technology, few can compete with the invention of the sports bra. Following the passage of Title IX in 1972, women’s interest in athletics surged. But their breasts presented an obstacle.

Bouncing breasts hurt, as women getting in on the jogging craze found out. Then some friends in Vermont had an idea to stitch a couple jock straps together to build a contraption to keep things in place.

Their creation revolutionized women’s participation in sports and launched what’s become a multi-billion-dollar industry.

Today, high-tech labs are helping designers make ever more effective—and stylish—iterations, even for athletes with DDD cups.

Outside contributing editor Florence Williams, author of Breasts, looks back at the game-changing invention, takes measure of just how far we’ve come, and points towards an even brighter, bounce-free future.

This featured story was produced by Phoebe Flanigan and edited by Peter Frick-Wright, with music by Robbie Carver and Dennis Funk. XX Factor: How the Sports Bra Changed History was originally aired on the Outside podcast, a production of Outside Magazine and PRX.