Roller derby is a growing, popular sport, where teams compete on roller skates, and where rules allow ‘blocking’ and full body contact. Roller derby is primarily played by women, with men restricted to support roles during its revival stage in the early 2000s. However, men and gender diverse skaters are increasingly playing the sport, in mixed/co-ed leagues and Men’s teams. This has created deep divisions within the derby community regarding the role of men in a women’s space and the playing of a full-contact sport with men against women on the track. The tensions within derby highlight the wider gendered problems in sport regarding perceptions of athletic ability, strength and capability. Drawing on an ethnographic methodology, we present a range of perspectives from derby players and counter-point their lived experiences with the structural constraints on gender enforced by the governing bodies with the sport Women’s Flat Track Derby Association and Men’s Roller Derby Association. We explicitly engage from a radically inclusive position inspired by Hargreaves’ call for sport to challenge gendered notions of capability.