Modern roller derby has a basic set of rules, with variations to reflect the interests of the governing body member leagues . The following summary is based on the rules of the Women’s Flat Track Derby Association (WFTDA).
Roller derby is played in two periods of 30 minutes each. Two teams of up to 15 players each field up to five competitors for episodes called “jams.” A jam lasts two minutes unless prematurely canceled. Each team designates a scoring player (“jammer”); the other four members are “blockers.” One blocker may be designated as a “backstop” – a blocker who is allowed to become a jammer during the course of the game. The next jam may feature different players from the 15 players on the list, as well as different choices of jammers and supports.
During each jam, players roll counterclockwise on a circular track. Only the team’s jammer is scored. After breaking through the pack and completing one lap to begin a new “journey” through the group, the jammer receives one point for passing any blocking opponent. The rules describe an “earned” pass; specifically, the jammer must be within the court and upright. The first earned pass by a jammer gives a point for passing that blocker and one point for each blocking opponent not on the track (e.g., serving a penalty or when the opponent has not fielded five players to block). If the jammer goes through the entire pack, it is a four-point trip, commonly referred to as a “big hit.”
Blockers on each team use body contact, position changes, and other tactics to help their jammer score points while obstructing the opposing team.
The game begins by lining up the blockers on the track somewhere between the “line of interference” and the “turn line” 30 feet in front of them. The jammers start behind the jammer line. Jamming starts with one short whistle, after which both jammers and blockers can immediately engage.
The pack is the largest group of blockers, with members of both teams rolling in close proximity, positioned so that each player is within 10 feet of the next. The blockers must support the pack, but are free to move within 20 feet behind and in front of it, in an area known as the “kill zone.”
The first jammer to break through the group gains the status of “lead jammer. “. The designated referee blows the whistle twice, rides next to the leading jammer and points to him/her. Earned lead jammer status cannot be transferred to other skaters, but certain actions (particularly getting into the penalty area) may result in its loss. A lead jammer can stop a jam at any time by repeatedly placing both hands on their hips. If the jam is not stopped early, it will be over in two minutes. If time remains in the period, teams have 30 seconds to get on the track and line up for the next jam. If the period expires, it doesn’t stop the jam from happening.
A skater may block an opponent to impede their movement or to force them out of bounds. The blocker must stand upright, skate counterclockwise, within and in the combat zone. Blocking with hands, elbows, head and feet is prohibited, as is contact above the shoulders or below mid-thigh and blocking from behind.
Referees penalize for infractions of the rules. The player receiving the penalty is removed from the game to sit in the penalty box for 30 seconds of the sticking time. If the jamming ends during this interval, the player remains in the penalty box during the subsequent jamming until the interval is over. The penalized player’s team plays at short tables, like ice hockey .
It would be pointless to play if neither team could score; thus, the jammer is released from the penalty box early if the opponent’s jammer enters the penalty box. The penalty for the second jammer will be equal to the time the first jammer spent in the box. A player is “trespassed” after the seventh penalty and must return to the locker room.
Equipment
Players skate on four-wheeled (“quad”) roller skates. , and must wear protective equipment including helmet, wrist guards, elbow pads, kneepads and mouth guards. All current roller derby rule sets explicitly prohibit roller skates for players. (USARS requires quad skating for all skaters. WFTDA and MRDA allow roller skates for referees, but virtually all referees wear quads.) Individual teams may require additional gear such as knee-length padded pants similar to those worn by aggressive skateboarders, and gender specific gear such as a hard case sports bra for female players and protective cups for men.