Roller Derby is a full-contact sport on quad roller skates. Every game (or “bout”) lasts 60 minutes and is divided into two 30-minute periods. Each period is a succession of “jams”, each lasting no more than two minutes, with 30-second breaks between jams. Players are substituted during these breaks. Each team fields 5 players per jam, 4 blockers and one jammer. The jammer is the only player able to score points. One point is awarded every time a jammer passes the hips of a blocker from the opposing team (a blocker can yield only one point per lap, such that a jammer can score a maximum of 4 points per trip around the track). The blockers work on both offence and defence. Their job is to block the opposing jammer with their hips, booty and shoulders and clear the path for their own jammer at the same time. 

The game follows rules that discourage dangerous actions, such as blocking to another player’s back or use of elbows, while allowing the game to remain exciting. Breaking the rules usually results in earning a 30-second trip to the penalty box, during which the team skates short and is at a tactical disadvantage. If a jammer commits a penalty, the opposing team has a chance to focus purely on offense during their 30-second “power jam”.

The team with the most points at the end of the game wins!