What is Derby?

Roller derby is a full contact sport played by two teams of five members roller skating in the same direction around a track. Game play consists of a series of short jams in which both teams designate a scoring player (the "jammer") who scores points by lapping members of the opposing team. The teams attempt to assist their own jammer whilst hindering the opposing jammer—in effect, playing both offense and defense simultaneously. Roller Derby is an international sport played by all-female teams.