The roller derby revival which began deep in the heart of Texas in 2003 has spread expansively across North America. Stripped of the big business financing and public consciousness of its high-water mark in the 70's, the sport has been transformed into a fiery subculture of gritty determination, progressive diversity and personal development, each new league a semi-clandestine accomplishment against the odds.

Today’s derby is a grassroots reboot of the basic concept – two teams of skaters scoring points by passing opposing players and preventing the other side from doing the same – where grace and agility are met with bursts of punishing, controlled violence. For spectators it can be an acquired taste; the mechanics of roller derby might seem monotonous, like a demolition version of NASCAR. But what’s going on beneath the surface, at the sidelines and in the hallways, is an exceptional sporting culture of amateur athletes immersed in a calling which makes room for everyone and tests everything: strength, endurance, confidence and will.

They aren’t just playing to win. They skate to expunge personal demons, bury turbulent pasts and smash current frustrations, and it gives the game an incendiary passion both on and off the track. That intensity, however, is always undercut by kindness, modesty and a touching empathy. The bonds forged between teammates can be profoundly deep. They love their sport, and it loves them back.