A game played on either a flat track or banked track. Members of both teams wear quad skates and circle the track in packs. The pack for each team consists of a pivot and three blockers.
There is also a jammer for each team on the track who tries to score points by passing opposing blockers. The blockers job is to keep the opposing jammer from getting through the pack and to assist their own jammer through.
Roller derby is a full contact sport, where players are encouraged to knock down their opponents by hitting them (also called blocking). Each league maintains their own rules of blocking.