Roller Derby is a contact, team sport where participants roller skate around a circular track, and attempt to score points by lapping members of the opposing team.

Roller derby is a physical sport where teams of skaters travel around a circuit track on roller skates. Designated players on each team score points by quickly skating past a grouping of other players. Generally a woman's sport, roller derby is known for its sometimes violent matches and campy aura.

Score more points than the opposing team by skating past a back of would-be blockers.

All roller derby matches are held on circuit tracks, and consist of two 30-minute periods. Matches are between two teams of five. Teams consist of three blockers, one pivot and one jammer. Helmet covers are used to display each player's position. Pivots and blockers start the game by forming a single pack. The pivots line up next to each other, followed by a layer of two blockers. The two jammers position themselves 20 feet behind the pack. Packs move counterclockwise around the track until they've reached the original starting point. At this point the referee blows the whistle, signaling the beginning of a jam. During a jam, points can only be scored by jammers, who move counterclockwise in an attempt to pass the pack and lap around as many times as possible. After passing the pack once, jammers earn one point each time they legally pass an opposing blocker or pivot. The first jammer to pass all pivots and blockers becomes the lead jammer, and can stop the jam at will. The team with the most points at the end of the match is the winner.

Roller derby draws its roots from endurance roller skating races held in the 1920's. Physical contact was added in the 1930's to make the sport more appealing to spectators. The sport took root as a pop culture staple in the second half of the 20th century despite going through a number of ups and downs. In the 21st century a number of small roller derby organizations were created, focusing on camp and athleticism. Many of these organizations still exist today, and can be seen live or on television.

Helmet
Padding
Roller Skates

By nature roller derby is a dangerous sport. Common injuries include bruises and broken bones. A helmet and padding should be worn at all times.

Roller derby athletes must be strong, possess great balance and be excellent skaters. These skills are best attained through weight training and skating practice.

Blocker - defensive player; identified by a coverless helmet

Camp - deliberately exaggerated and theatrical in style, typically for humorous effect

Jam - two-minute period during which both teams attempt to score points

Jammer - scoring player; identified by a two-star helmet cover

Pivot - defensive player similar to a safety in football; identified by a striped helmet cover

http://en.wikipedia.org/wiki/Roller_derby