The development of stretch materials has had a profound impact on both active wear and fashion. These include Lastex yarn in the 1930s and, at the end of the 1950s, spandex (also known by the brand name, Lycra). Their suitability for swimwear quickly became obvious. By the 1980s, spandex could be found not only in specialized sportswear (for competitive bicycling, for instance) and in exercise and dance clothing, but also in similarly body-conscious fashions.

"Exercise clothes seem to be everywhere," wrote fashion journalist Allison Kyle Leopold in 1986. "Sneakers, sweatpants, leggings and tank tops — gear that is meant to be worn in the gym — have become a standard part of everyday dressing for exerciser and nonexerciser alike."

Norma Kamali’s 1980s sweatsuit fashion exemplified the proliferation of active sportswear as mainstream style. "Just when you thought the influence of active sportswear on street fashion was running out of breath, along sprints Norma Kamali," said the New York Times in April 1981. The newspaper was referring to Kamali’s line of fashion garments crafted from the humble gray cotton of gym sweatshirts. "The Hot-Selling Locker Room Look" — as Time magazine called it — could be worn nearly anywhere.