There are two 30-minute periods in a game, and each jam is two minutes long. At the start of the jam, each team sends out five skaters: four blockers and a jammer. The jammer wears a star on their helmet. The jammers try to get past the opposing team’s blockers, and the blockers try their best to stop the jammer from passing them. After the jammer passes all of the blockers once, they start earning one point for each opposing blocker they pass. The first jammer to get out becomes the “lead jammer” and they have the power to call off the jam.