There was a time in our not so distant past—before 1977, to be exact—when sports bras didn’t exist. And considering how awkward and uncomfortable it is for the boob-endowed to run, jump, or move vigorously without a sports bra, we were surprised to learn its a relatively recent invention.

Lisa Lindahl, the creator of the sports bra, is used to this reaction. “I’ve met plenty of people who are surprised that the creator of the sports bra is still alive,” she says letting out a laugh.

Lindahl was a grad student at the University of Vermont in the mid-1970s when she picked up jogging as a hobby. Her sister, Victoria Woodrow, mentioned she was interested in running too, and asked Lindahl what kind of bra she wore. The unfortunate answer: Lindahl usually doubled up on bras or wore one that was a size too small to give her the support she needed mid-run. (Ouch!)

Women’s undergarment company Glamorise came out with the Free-Swing Tennis Bra in 1975, a first attempt at sportswear-meets-lingerie for women, but it was a far cry from the sports bra we’re used to today. Advertisements for the Free-Swing suggested it was best suited for leisurely sports, such as golf or sailing.

Woodrow joked that women needed the equivalent of a jockstrap for their breasts—or at least a bra with straps that wouldn’t fall off and fasteners that wouldn’t dig into the skin. Lindahl couldn’t get the idea of a specialized athletic bra out of her head, so she approached her friend Polly Smith, a costume designer, for help. The two women came up with a number of initial mockups, but nothing seemed to fit—either the prototype was too tight or didn’t give enough support. That is, until one day when Lisa’s husband at the time paraded around the house with an upside down jockstrap across his chest. The next day, Smith cut apart two jockstraps, sewed them together, and the first jockbra was born.

The design of the jockbra (which was later known as the jogbra and then the sports bra), was improved from its beta version (which simply mimicked a jockstrap), but the crossed straps in the back and supportive elastic band under the breasts remained. Lindahl says she thought jockbra would be a small mail-order business she could do on the side while she was in graduate school.

With Title IX, which prohibits gender-based discrimination in schools, and the increasing popularity of jogging throughout the 1970s, more women were exercising than ever before. When Lindahl placed a small ad for the jockbra in a running magazine, her mailbox started to overflow with orders. Four decades later, sports bras have become just as common as yoga pants and a good pair of running shoes.