Roller derby is sport which is played by two teams, and they are roller skating in the same direction around a track. The sport was developed from roller skating marathons in the 1930’s.
The teams consists of five players each, there should be fourteen players on a roster. Roller derby consists of short matchups, which is also called jams, the teams assign a scoring player, or the jammer, who should score points by lapping the opposing team’s members. The blockers assist the jammer and they try to hinder the jammer of the opposing team.
The players can knock the opposing team out of the bounds. There are certain rules for legal blocks, contact mad by hands, elbows, head, feet, shoulders, and mid-thigh are not allowed. Roller derby is played indoors in a roller rink. Some of the equipment used are roller skates, helmets, knee pads, elbow pads, wrist guards, and a mouth guard.