Roller Derby is played on a flat oval track, the so-called “flat track”. The playing time is divided into two halves of 30 minutes each, consisting of an unlimited number of jams with a maximum of two minutes. The teams start with five players each. Among them are four blockers including the pivot and the jammer.
The jammer is marked by a helmet cap with a star and collects points for the team by legally overtaking the opposing blockers. She starts behind the “pack” (the group of blockers and pivots of both teams). The jammer who makes it through the pack first is the “lead jammer” and can therefore break off the jam early. The sign of this is the knock with the hands on the hip. The aim of the blockers is to support their own jammer by maneuvering and/or tackling and also to prevent the opponent jammer from scoring points.
The allowed use of the body is exactly defined in the rules and is monitored by up to 21 officials during the game. Among them are also the referees. Anyone who violates the rules will be sent to the “penalty box” and must serve his 30-second penalty.