The first Women’s World Cup was in 1991, and the games were only 80 minutes, compared to the 90-minute games played by men. Part of the rationale was that women just weren’t tough enough to play a full 90 minutes of soccer.This idea of women as the “weaker sex” is everywhere in early scientific studies of athletic performance. Sports science was mainly concerned with men’s abilities. Even now, most participants in sports science research are men.Luckily things are changing, and more girls and women are playing sports than ever before. There’s a little more research about women too, as well as those who fall outside the gender binary.SciFri producer Kathleen Davis talks with Christine Yu, a health and sports journalist and author of Up To Speed: The Groundbreaking Science of Women Athletes, about the gender data gap in sports science.Read an excerpt of Up to Speed: The Groundbreaking Science of Women Athletes at sciencefriday.com.Transcripts for each segment will be available after the show airs on sciencefriday.com.  Subscribe to this podcast. Plus, to stay updated on all things science, sign up for Science Friday's newsletters.