What is roller derby?
"You kind of describe it as rugby on skates without the ball."
The game is between two teams — each team has four blockers and one jammer.
"The aim of each jammer is to get through the opposition's four blockers."
Once through the jammer scores points by lapping members of the opposing team.
"There's lot of rules and strategies.
"It can get a little bit crazy out there but it's fun and everyone has a great time.
"It's also very sociable sport."
Kapiti Coast Derby Crew, nicknamed KC/DC, has been on the coast for six years.
The club caters for a range of people, both male and female, from the age 16.
It has a learn to skate programme, which Gemma coaches, in the Waikanae Memorial Hall on Monday nights.
When players have progressed through their training they go onto game preparation which takes place at the new Kāpiti College gym on Sunday nights.
The doors to the gym, for Saturday's big game, open at 1.30pm. Adults $5, kids $2, under 5s free.
"We will have a coffee cart there and hopefully some merchandise for sale," Gemma said.
"Bring the kids along."