The basics:
A league is typically made up of two or more teams. Each team plays as part of the same league, but bout in competition against each other. Each team is made up of an assortment of skaters with differing skills and abilities. On each team, you will find both fast and agile skaters, as well as solid, hard hitting skaters. Both are extremely important to the game and no one body type is at an advantage or disadvantage in the sport.
A game or bout is played between two opposing teams. A bout consists of two thirty minute halves with each half being broken down into two minute Jams.
For each bout, up to 14 players can be registered for a team, but a team’s full lineup for a single jam will consist of five players – one pivot, three blockers and one jammer. Each team may field up to five players for each jam.

Blocker – The other three blockers do not wear helmet covers. All blockers may play offense anddefense at any given time and frequently switch between offensive and defensive tasks. The rules do not differentiate between the remaining three blocking positions, however most Roller Derby teams choose to assign names and focus areas to the blocking positions for strategic purposes.
Jammer – The jammer wears a helmet cover with a star on it. They line up at the second starting line and begin play at the second start whistle. The jammer’s goal is to pass opposing blockers and emerge from the pack as quickly as possible. If they are the first of the two jammers to escape the pack without committing any penalties, they gain the strategic advantage of being able to stop the jam at any time by placing their hands on their hips.Once a jammer laps the pack, they begin scoring one point for every opposing blocker they pass legally. They can continue to lap the pack for additional scoring passes for the duration of the jam.
The Jammer can also score points on opponents who are in the penalty box and can get a fifth point if they lap the opposing jammer. Blockers are trying to stop the opposing team’s jammer while helping their own jammer get through.
Are there any rules or penalties?
For all the rules and penalties, check out the official WFTDA Rules.
Here is a brief outline:
• No tripping
• No back blocking (pushing from behind)
• No deliberate falling in front of another skater
• When using arms for blocking, the arm must be bent, not extended
• No use of elbows as a weapon to the chest or face
• No blocking 20 feet ahead of or behind the pack
• No grabbing or pulling a skater from the ground
• It is illegal to GRAB, HOLD or PULL an opposing player – so hands off!
If a skater is in the penalty box and the jammer from the other team passes through the pack, they will still get a point for the missing skater who is in the penalty box. So the penalty is truly only against the team who is losing a player for that period of time and not against the other team who is trying to score points.
A jammer can be put into the penalty box which creates a scoring opportunity for the opposing team. If both jammers end up in the penalty box, the first jammer in the box is allowed back on to the track as soon as the second jammer reaches the box.