Roller Derby Origins
While the sport has its origins in the banked-track roller skating marathons of the 1930s, Leo Seltzer and Damon Runyon are credited with the basic evolution of the sport to its initial competitive form.
Professional roller derby quickly became popular. In 1940 more than 5 million spectators watched in about 50 US cities. In the ensuing decades, however, it predominantly became a form of sports entertainment where the theatrical elements overshadowed the athleticism. This gratuitous showmanship largely ended with the sport's contemporary grassroots revival in the first decade of the 21st century. Although some sports entertainment qualities such as player pseudonyms and colorful uniforms were retained, scripted bouts with predetermined winners were abandoned.
Modern roller derby is an international sport dominated by all-female amateur teams, in addition to a growing number of male, co-ed, and junior roller derby teams, and was (as a roller sport) under consideration for the 2020 Olympics. Most modern leagues (their back-office volunteers included) share a strong "do it yourself" ethic which combines athleticism and commitment .
As of 2014 the Women's Flat Track Derby Association, or WFTDA, had 234 leagues. The Mens Roller derby Association or MRDA with 43 leauges as of 2014 and now this group also includes The Junior Roller Derby Association or JRDA with 67 leagues world wide.