ROLLER derby is an American-invented contact sport which dates back to the 1920s.

It is a full-contact women's sport played on quad roller skates, by players skating around an elliptical track. The game consists of a series of two-minute countdown jams.

Each game consists of two 30-minute periods. Each team sends five players onto the track: one jammer (point scorer), three blockers (defensive/offensive players) and one pivot (last line of defence and lead blocker). The jammers' aim is to make it through the pack and skate a full lap to re-enter the pack again. Once they do so, they score a point for each opposing skater they pass legally.