Roller derby is a roller skating contact sport played on an oval track by two teams of five skaters. It is played by approximately 1,250 amateur leaguesA Roller Derby league is synonymous with an individual club or team in other team sports, as opposed to the more typical use of the word league. worldwide, though it is most popular in the United States.

A 60-minute roller derby game, or bout, is a series of two-minute timed jams. Each team, typically with a roster of 15, fields five skaters during each jam: one jammer, designated with a star on their helmet, and four blockers. During each jam, players skate counterclockwise on a circuit track. The jammer scores a point for each opposing blocker they lap. The blockers simultaneously defend by hindering the opposing jammer, while also playing offense by maneuvering to aid their own jammer. Because roller derby uses a penalty box, power jams, in which one team has a temporary numerical advantage after a foul, can have a major effect on scoring.

Overview While the sport has its origins in the banked-track roller-skating marathons of the 1930s, Leo Seltzer and Damon Runyon are credited with evolving the sport to its competitive form. Professional roller derby quickly became popular; in 1940, more than 5 million spectators watched in about 50 American cities. In the ensuing decades, however, it predominantly became a form of sports entertainment, where theatrical elements overshadowed athleticism. Gratuitous showmanship largely ended with the sport's grassroots revival in the first decade of the 21st century. Although roller derby retains some sports entertainment qualities such as player pseudonyms and colorful uniforms, it has abandoned scripted bouts with predetermined winners.

Modern roller derby is an international sport, mostly played by amateurs. It was under consideration as a roller sport for the 2020 Summer Olympics. Fédération Internationale de Roller Sports (FIRS), recognized by the International Olympic Committee as the official international governing body of roller sports, released its first set of Roller Derby Rules for the World Roller Games, organised by World Skate, that took place September 2017 in Nanjing, China. Most modern leagues (and their back-office volunteers) share a strong "do-it-yourself" ethic that combines athleticism with the styles of punk and camp. , the Women's Flat Track Derby Association (WFTDA) had 451 full member leagues and 46 apprentice leagues and the Roller Derby Coalition of Leagues (RDCL) supporting women's banked track roller derby had eight full member leagues.

Rules

Contemporary roller derby has a basic set of rules, with variations reflecting the interests of a governing body's member leagues. The summary below is based on the rules of the Women's Flat Track Derby Association (WFTDA). In March 2010, Derby News Network said that more than 98% of roller derby competitions were conducted under WFTDA rules. For example, members of the United Kingdom Roller Derby Association are required to play by WFTDA rules, while members of the former Canadian Women's Roller Derby Association were encouraged to join the WFTDA.

Basics of play Roller derby is played in two periods of 30 minutes. Two teams of up to 15 players each field up to five members for episodes called "jams". Jams last two minutes unless called off prematurely. Each team designates a scoring player (the "jammer"); the other four members are "blockers". One blocker can be designated as a "pivot"—a blocker who is allowed to become a jammer in the course of play. The next jam may involve different players of the 15 roster players, and different selections for jammer and pivot.

PositionHelmet coverResponsibilityJammerStarScores points by lapping opposing blockers.BlockerNoneForms the pack, hinders the opposing jammer from passing through the pack, and helps their team's jammer pass through the pack.PivotStripeA blocker who may be converted to a jammer during the course of a jam, if the jammer's helmet cover is correctly transferred in a "star pass" maneuver. The pivot is often an experienced player who establishes team strategy during play and sets the pace of the pack.

During each jam, players skate counterclockwise on a circuit track. Points are scored only by a team's jammer. After breaking through the pack and skating one lap to begin another "trip" through the pack, the jammer scores one point for passing any opposing blocker.Until 2019, the jammer also scored a point by passing the opposing jammer. There were 5 potential points per trip. The rules describe an "earned" pass; notably, the jammer must be in-bounds and upright. The jammer's first earned pass scores a point for passing that blocker and a point for each opponent blocker not on the track (for instance, serving a penalty, or when the opposition did not field five players for the jam). If the jammer passes the entire pack, it is a four-point scoring trip, commonly called a "grand slam".

Each team's blockers use body contact, changing positions, and other tactics to help their jammer score while hindering the opposing team's jammer.

Jams

Play begins by blockers lining up on the track anywhere between the "jammer line" and the "pivot line" in front. The jammers start behind the jammer line. Jams begin on a single short whistle blast, upon which both jammers and blockers may begin engaging immediately.

The pack is the largest single group of blockers containing members of both teams skating in proximity, arranged such that each player is within of the next. Blockers must maintain the pack, but can skate freely within behind and ahead of it, an area known as the "engagement zone".

The first jammer to break through the pack earns the status of "lead jammer". A designated referee blows the whistle twice and continually points at the jammer to confer lead jammer status, which lets that jammer stop the jam at any time by repeatedly placing hands on hips. Lead jammer status cannot be transferred to other skaters, but certain actions (such as being sent to the penalty box) cancel lead jammer status, meaning that the jam has no lead jammer and must continue for the full two-minute period. If the jam is not called off by the lead jammer, it ends after two minutes. If time remains in the period, teams then have 30 seconds to get on the track and line up for the next jam. If the 30-minute period ends while a jam is underway, the jam plays out to its natural conclusion.

Blocking

A skater may block an opponent to impede their movement or to force them out of bounds. The blocker must be upright, skating counterclockwise, in bounds, and within the engagement zone. Groups of blockers on the same team typically create formations, known as walls, to prevent the opposing blocker from passing. Blocking with hands, elbows, head, and feet is prohibited, as is contact above the shoulders, below mid-thigh, or to the back.

Penalties

Referees penalize rules violations. A player receiving a penalty is removed from play and must sit in the penalty box for 30 seconds of jam time. If the jam ends during this interval, the player remains in the penalty box during the subsequent jam until the interval ends. While the penalty is being served, the penalized player's team plays short-handed, as in ice hockey. A player "fouls out" of the game on the seventh penalty, and is required to return to the locker room.

A "power jam", derived from ice hockey's "power play", refers to a scenario when one team's jammer is sent to the penalty box. In this case, that jammer's team cannot score. The opposing team's blockers typically switch to playing offense for the duration of the other jammer's penalty. If the lead jammer is penalized, no one can prematurely end the jam.

It would be pointless to play if neither team could score; thus, both jammers cannot serve a penalty at the same time. If one jammer is sent to the penalty box while the opposing jammer is already serving a penalty, the opposing jammer is released from the penalty box early. The second jammer's penalty is then only as long as the amount of time the first jammer spent in the box.

Equipment

Players skate on four-wheeled ("quad") roller skates, and are required to wear protective equipment, including a helmet, wrist guards, elbow pads, knee pads, and mouth guards. All current sets of roller derby rules explicitly forbid inline skates for players. (USARS requires quad skates for all skaters. WFTDA and MRDA permit inline skates for referees, but virtually all referees wear quad skates.) Individual teams may mandate additional gear, such as padded knee length pants, similar to what aggressive skateboarders wear, and sex-specific gear such as a hard-case sports bra and protective cups.

Strategy and tactics Offense and defense are played simultaneously, a volatile aspect that complicates strategy and tactics. For example, one team's blockers may take offensive action to create a gap in the opposing wall for their jammer to pass through, but this same maneuver could potentially weaken their own defenses and allow the opposing team's jammer to score.

Strategies (high-level plans toward achieving the game's goal, which is to outscore the opposition) include the following: Ending the jam: The lead jammer can "call off" or end the jam at any time, controlling the opposition's ability to score points. The strategy for a jam is not to score a lot of points but to outscore the opposition. Often, the lead jammer scores as many points as possible on the first scoring trip, and then ends the jam before the opposing jammer has the opportunity to score any points. If the jammer gets the lead but is then passed by the opposing jammer, they may decide to call off the jam without scoring any points themself in order to prevent the other team's jammer from scoring any points. Passing the star: The jammer for a team may "pass the star" (may perform a "star pass") to the pivot—that is, hand the helmet cover with the star to the pivot, which turns the pivot into the jammer. Passing the star does not nullify any earned pass of an opponent that the former jammer made, but passing the star forward never constitutes an earned pass. A jammer might pass the star because of fatigue, injury, or because the pivot is in a better position to score. Passing the star is also sometimes referred to as "passing the panty", as helmet covers are sometimes known as "panties". Killing a penalty: Captained by the pivot, blockers adapt their play to a penalty situation. For example, a short-handed team may try to make the pack skate faster to slow down scoring action until the team returns to full strength.Before 2013, there were "major" and "minor" penalties, the former included any player's fourth penalty, and it was strategic for a key player to deliberately commit such a penalty when it would have least effect.

Tactics (deliberate conceptual tasks in support of the strategy) may include the following: Walling up: Two or more blockers skate together to make it difficult for the opposing team (especially its jammer) to maneuver. They may skate side by side and use a "wide stance" to maximize the blockade, but must not link with or grasp each other, or otherwise form an impenetrable connection. The ability to suddenly form a wall denies the opposition time to respond. A wall can inhibit, slow down, and ultimately trap the opposing jammer. An effective wall may last for an entire jam. Variations on the tactic include the following: Backwards bracing, in which one skater, forward of the wall, skates backward to sight the jammer and direct teammates forming the wall. A skater may break off from the wall to actively challenge the opposing jammer, with a teammate replacing the skater in the wall. If the opposing jammer tries to pass the wall on one side, players may abandon the other side to fortify the active side of the wall.