Roller Derby Basics
A bout (game) consists of two 30-minute periods, broken up into 2-minute jams. Between jams there are 30-second breaks for substitute skaters to reset in their starting positions. If all skaters are not in position at the beginning of the jam, the jam will start without them and their team will skate short.
BASIC GAME PLAY
A single whistle from the jam timer gets the pack and jammers started. A jam ends with four rapid whistle blows.
Blockers try to impede the opposing jammer while trying to get their own jammer through the pack. The first jammer to pass through the pack legally and in-bounds becomes the "lead jammer." The jam referee will signal this by pointing at the lead jammer and making an "L" with their left hand held high above their head.
Once their initial pass has been completed, jammers may begin to score points. Jammers score one point for each blocker they legally pass (hips in front of hips) on each subsequent pass through the pack. Passing all opposing blockers gives 4 points.
The lead jammer may choose to end the jam strategically by touching their hands to their hips repeatedly. If there is no lead jammer, the jam will last a full two minutes. This is known as a "power jam." A jam ends with four short whistle blasts, and points may continue to be scored until the fourth and final whistle blast.