Five per side.
One star each.
In each jam, a team fields a jammer and up to four blockers. One blocker can be the pivot. All ten skaters share the flat oval; both teams are trying to help their own jammer and slow the other.
JAMMER
Scores the points.
PIVOT
A blocker who can receive the star.
BLOCKER
Defense and offense in the same jam.
Jammers begin behind the jammer line. Blockers start between that line and the pivot line, with specific pivot positioning privileges. Play proceeds counterclockwise. Helmet covers identify roles; they are not extra players or protective helmets themselves.
The first trip opens the door.
In an ordinary jam, the jammer’s initial trip through the pack is scoreless. After coming around, the jammer can score one point for each opposing blocker legally lapped. Points require earned passes under the rules, including the visible star and the applicable position requirements.
Four is the normal full-trip value, not a cap on the jam. A jammer can complete more scoring trips. Passing the other jammer adds no extra point. Rules also account for blockers who are not available to pass, so you cannot infer every point from four visible overtakes.
Watch a four-point pass in the track lab. The simple sequence leaves penalties and other scoring exceptions out.
Lead controls the exit.
The first eligible jammer to earn the required passes and gain position ahead of the foremost in-play blocker is awarded lead. The referee signals that status. It is not automatically the skater who happens to be ahead later in the jam.
Lead may end the jam early by repeatedly putting hands on hips. A jammer who scores while the opponent is still approaching may use this to protect the point advantage. Play ends through the officials’ four-whistle ending sequence.
Lead can be lost, including by committing a penalty or intentionally removing the star. A legal star pass changes the jammer, but does not transfer lead. Read what changes during a star pass before treating a cover in someone’s hand as a completed transfer.
A moving playing area.
The pack is the largest group of upright, in-bounds blockers in proximity, containing members of both teams. Proximity is up to ten feet to the nearest pack skater ahead or behind. Jammers are excluded from that definition.
The engagement zone reaches twenty feet forward and backward from the pack. Blockers outside it are out of play. If no single group qualifies as the pack, blockers must work to reform it; they cannot simply keep engaging as though nothing changed.
Read the pack guide for how group size, bridging and no-pack situations change the play.
Contact has boundaries.
Legal contact depends on the target, the body part used to initiate it, the skaters’ positions and the action’s effect. A legal target is not necessarily a legal blocking tool. Hands and forearms, for example, cannot be used to initiate a block.
A penalty normally costs thirty seconds of jam time in the box, with the final ten standing. Timing pauses between jams. Jammer penalties have special release rules when both jammers report. Seven recorded penalties foul a skater out; serious conduct can also lead to expulsion.
Decode the whistle for legal contact zones, position and penalty timing. Learn contact under a qualified trainer and use the rulebook’s casebook for close calls.
Two clocks. Different jobs.
| Clock | What it does |
|---|---|
| Period | Two periods of 30 minutes. The clock normally continues between jams. |
| Jam | Up to two minutes, unless ended earlier. |
| Lineup | 30 seconds between jams, unless a timeout changes the sequence. |
| Penalty | Normally 30 seconds of jam time, with special rules for jammer releases. |
If the period clock reaches zero during a jam, the jam plays to its end. A tied game can require overtime. In overtime, both jammers start scoring on the initial trip, neither can earn lead, and the jam runs for the full two minutes unless officials end it for a separate reason.
This reference explains WFTDA flat-track rules. A banked-track game, another ruleset or a modified training format can work differently.
The words you’ll hear.
- Bout
- A roller derby game.
- Jam
- A unit of play lasting up to two minutes.
- Jammer
- The skater whose role can earn points. Identified by the star.
- Blocker
- A skater working to impede the other jammer and help their own.
- Pivot
- A blocker identified by the stripe, eligible to receive a legal star pass.
- Lead
- A status awarded to the first eligible jammer meeting the lead requirements. It allows an early call-off.
- Initial trip
- The first trip through the pack. In ordinary jams, it earns no points.
- Scoring trip
- A later trip on which a jammer can legally lap blockers for points.
- Call-off
- An early end requested by the lead jammer.
- Star pass
- A legal handoff from jammer to pivot that transfers the jammer role.
- Pack
- The largest qualifying group of upright, in-bounds blockers from both teams in proximity.
- Engagement zone
- The area extending 20 feet ahead of and behind the pack.
- Power jam
- A situation in which one jammer is penalized while the other can score.
- NSO
- Non-skating official. A member of the crew working roles such as timing and recording.
- Bridge
- A blocker or connection of blockers maintaining proximity between groups.
- Offense
- Work that helps a team’s own jammer make progress.
The rulebook gets the last word.
Based on the WFTDA rules site, version 20250101, checked September 11, 2026. This is an independent introduction. The full rules, casebook and official interpretations resolve exceptions our examples leave out.