Amanda Calabrese has traveled all over the world as a competitive lifeguard—picture a decathlon, but at the beach—diving into 15-foot waves in South Africa and sprinting across Italian beaches. But she struggled to find a tampon that wouldn’t leak during competitions. During her senior year at Stanford University, she met up with fellow student athlete Greta Meyer, who struggled with the same issue as a Division 1 lacrosse player. Together, they raided pharmacy shelves, filled their dorm room with tampons and tore them apart to sew them back together in new structures. What they discovered led them to found their women’s health startup, Sequel. It’s a tough journey ahead—they continue to wait for final Food and Drug Administration approval before they can begin selling their tampons—but they raised $5 million from Pear VC and Mac Venture Capital to help them get there. Here, the women share how their background as athletes inspired their invention.