TO her students at Woodcrest State College she's known as Ms Kovacevic, a mild-mannered, senior school art teacher.
But when Kimberley Kovacevic straps on her roller derby gear, she transforms into KimboKazee a fast and furious roller derby skater for the Nasty Nancies.
Since she joined the sport two years ago, the 31-year-old has become a fierce competitor within the Brisbane City Rollers, a roller derby league based in Ipswich.
The sport, which has seen an explosion in popularity, is a fast-paced, full contact game played out on quad roller skates.
In Australia alone, there are now more than 1000 registered skaters with 21 leagues spread across all seven states.
Springfield Lakes web designer Cass Van Wyk, who competes under the name Chaser on the Rocks, said being involved in the league was like being a part of a big family.
"It's fantastic, everyone welcomes you with open arms and you develop such great friendships," she said.
A former figure skater, the 32-year-old said it had been a challenge adopting a new style of skating that involved hitting people.
"But most derby leagues have a fresh meat program to teach you the rules as well as derby roller skating technique," she said.
While modern roller derby is dominated by all-female teams, men's roller derby is also starting to grow.
Oxley's Elton Christiansen, known on the track as Hellton, has been heavily involved in the sport for more than three years.
The father of two said men currently had limited opportunities, but more and more men's leagues were starting up around the country.
Christiansen, who competes in the league with his wife, said he was trying to raise the profile of men's derby by working with other male skaters interstate.
"The game is really quite exciting," he said. "My wife and I are very supportive of each other and very proud of what the other has achieved within the sport."
The next Brisbane City Roller event will take place at the Ipswich Showgrounds on July 28, with games played throughout the day. For more information on the league and its events visit www.brisbanecityrollers.com.