By Audrina Bigos

(CBS) – It’s a big week for roller derby, a sport that began in Chicago more than 80 years ago.

The sport may have reached its pinnacle here, when 50,000 people packed old Comiskey Park in September 1972. The derby rink was on the pitcher’s mound.

A Chicagoan named Leo Seltzer invented the sport. He put on the first roller derby at the Chicago Coliseum in August 1935.

“The kids who are playing today, who are involved in derby — they’re playing it for real,” says Chet Coppock, who announced that 1972 event.

After a decades-long drought, the Windy City Rollers were part of a grassroots resurgence of the sport in the early 2000s.

“A lot of people that still remember it are from my parents’ generation, where it was very WWF,” Kristina Rago says.

Now, they’re more skilled athletes.

“We definitely have started focusing a lot on cross training, making sure we’re strong and fit,” Nicole Negrete says.

There are now about 2,200 roller derby leagues, in 65 countries around the world.

This week, the sport is celebrating its Chicago roots with World Roller Derby Week. There’s a retro derby on Saturday to say happy 82nd birthday. For more information, click here.