The whistle blows, and the jammers set off smashing into a wall of blockers.
Limbs hit the floor and wheels screech around them but the skaters are up and off again.
This is the fast paced, contact sport of roller derby.
Find out all the rules, tips and ins & outs of roller derby, Europe's Fastest Growing Female Sport.
What it takes to be a roller derby skater
Core body strength and quick thinking are just a couple of things you need to be a good Roller Derby skater according to Courtney Welch, aka Bette Noir.
Bette is one of the co-founders of London Rollergirls, the UK's first roller derby league.
There are now over 100 leagues in the UK and is the world's fastest growing female sport.
Find out what all the fuss is about and how to get involved, as Bette explains what it takes to play roller derby.
Learn the rules
Roller Derby can look like havoc on the track if you don't know the basic rules, so it's not surprising that it take seven referees to officiate a game, not to mention the several none-skating officials!
These rules will give you a basic understanding of the positions and how to score during a game.
Bette Noir, co-founder of the first roller derby league in the UK explains the rules with two of the UK's best teams, the Middlesbrough Milk Rollers and Greater Manchester's Rainy City Roller Girls.
How to stop
First thing you need to learn if you are going to take up roller derby? How to stop!
Power stops, hockey stops, derby stops and power slides. In the game of roller derby there are many ways hit, turn and block your way to skating dominance.
This video will give you all the tips you need from one of the UK's best roller derby players, Fay Roberts, who plays internationally for England and in the Rainy City Roller Girls league.
How to hit
Making a hit in roller derby is all about getting really low, using your gluts and popping or pushing your opponent out of action.
London Rollergirls skater, Tess Robinson, takes us through the many different ways to achieve this with hits and blocks.
Watch the video and you'll soon discover it's all about lower body energy. So for serious power, get squatting and lunging and you'll be pushing and popping your opponent in no time!
The legal hitting zones
Roller Derby is a physical and full contact sport that will leave you with bruises (or derby kisses as they are also known) so it's important to always hit safely in order to avoid injury.
Magic Beans from the London Rollergirls takes us through a step-by-step guide to the legal hitting zones and the importance of skating in a safe manner.
When hitting and blocking, you can only attack the below the neck and above the knees. If hitting an opponent from behind, you cannot directly target their back or within the bra straps.
However, you're completely allowed to hit with your bum!
How to Apex Jump
Get low, then get up. The Apex Jump is one of the key techniques to escaping the blockers in Roller Derby.
It's a move where the skater cuts the inside of the track by jumping over it.
It's a legal move as long as the skater jumps from in-bounds, lands in-bounds and does not make contact with any other skaters in the process.
All you have to do is gain as much speed as possible, take off with your right, jump straight in the air, and land on your left. Bend your knees to make the landing easier and hope not to fall on your landing!
How to perform a Crabwall
Blockers can be most effective when they work together.
The London Rollergirls are back to give us a tutorial on how to perform a successful Crabwall.
A Crabwall is a defensive wall formation, covering the track in order to stop the opposing team's Jammers from weaving through and scoring points.
There are three Blockers and a backwards facing Blocker providing extra support and strength as the Jammer hits.
What are you waiting for? Get your skates on and take a look at our guide to Roller Derby.