Jammer
The only player who scores points. You can spot the jammer by the star on the helmet cover.
Goal: get through the pack, then pass opponents.
Roller derby
made simple.
Want to understand what's happening during a game? Start here. Learn who's who, how points are scored and when a jam ends.
01 • The roles
Who's on the track?
Each team normally has up to 5 skaters on the track: 1 jammer + 4 blockers. One of those blockers can be the pivot.
1 per team
Blocker
Helps their own jammer forward and tries to slow the other jammer down with positioning and blocks.
A team has at most four blockers; the pivot is one of them.
Pivot
A special blocker with a stripe on the helmet cover. Under certain conditions the jammer can pass the star to the pivot.
Remember: pivot = blocker with a stripe.
02 • The basic rules
What you need to know to watch
A jam lasts up to 2 minutes.
The jam can end sooner if the lead jammer calls it off.
Only the jammer scores.
The jammer earns points by lapping opponents.
The blockers form the pack.
They try to help their own jammer and hold back the other one.
A penalty can send a player to the penalty box.
There the player misses part of the jam.
The golden viewing tip 👀
Follow only the jammers at first. Look for the two stars on the helmets. Watch who gets through the pack first and which opponents they pass after that.
As a beginner you don't need to watch all the blockers, officials and tactics at once. If you can follow the jammers, you already understand a big part of the game.
03 • Legal pass
When does a pass count?
A pass = the jammer legally gets past an opponent
As a new spectator you can think of it like this: the jammer wears the Star, skates in the right direction and gets past an opponent without the pass being cancelled by a foul or by being out of bounds.
① Spot the jammer
Look for the star on the helmet cover.
② Watch the opponent
The jammer goes from behind the opponent to in front of them.
③ The officials decide
The officials officially decide whether the pass and its point count.
Rule of thumb: see the jammer legally get past a blocker? That's a moment the jammer can score. The official score is set by the officials.
04 • Lead jammer
How can a jam end early?
The lead jammer can call off the jam ✋
The lead jammer is the first eligible jammer to earn lead status by getting through the pack according to the rules.
The lead jammer can stop the jam before the 2 minutes are up by repeatedly putting both hands on their hips.
No lead jammer? Then no jammer can end the jam early this way. The jam runs to its full length, unless the game is stopped for another reason.
05 • Tactics
What happens in the pack?
Building a wall
Several blockers work together to hold back an opponent or make room for their own jammer.
The group
The pack is the group of blockers at the heart of the game. That's where much of the tactical work happens.
Splitting someone off
Getting a blocker away from the rest of the group means that player can't help as well.
06 • Example
A jam in five steps
Use these five steps as a viewing guide during a real game.
Step 1
Start
The jammers start behind the Jammer Line. The blockers line up in front and form the pack.
Step 2
Through the pack
Both jammers try to get through the blockers. Blockers help their own jammer and hinder the other.
Step 3
Lead
The first eligible jammer to earn lead status becomes lead jammer.
Step 4
Points
The jammer keeps going and can earn points by lapping opponents.
Step 5
End
The lead jammer can call off the jam with hands on hips. Otherwise the jam runs until time is up.
Example: Jammer A gets lead. A comes through the pack again and goes for points. Jammer B is closing in. A puts both hands on their hips → the jam stops. Points earned under the rules stay on the board.
07 • Terms
Tricky words in plain language
Click a term for a short explanation.
Jam
A period of play of up to two minutes.
Pack
The largest group of blockers from both teams that are close enough together to count as one group.
Lead jammer
The first eligible jammer to earn lead status. Only the lead jammer can call off the jam early.
Star
The jammer's helmet cover with the star.
Pivot / Stripe
The pivot is the blocker with the stripe on the helmet cover.
Lap
When a jammer passes an opponent for the second time relative to that opponent, it can earn an extra point.
Penalty box
The sin bin. A player who gets a penalty sits out here for a set time.
In bounds
Inside the boundaries of the track.
Out of play
Outside the area where blockers are allowed to take part in blocking under the rules.
NSO
Non-Skating Official: an official who isn't on skates and keeps track of things like score, penalties or time.
08 • See it in action
Watch the videos
The videos open on YouTube.
Video 1
Open the video on YouTube and use the explanation above to spot the jammers and the pack.
▶ Watch on YouTube09 • Test yourself
Mini quiz
1. How many jammers does each team normally have on the track?
Your score
0 / 5
Answer the questions to start.
10 • Official source
Want to know more?
This explanation is deliberately simplified for new spectators. For official definitions, exceptions and the full rules, the current WFTDA rulebook applies.