In this article we show how a hybridisation of elite sport and school in lower-secondary education in Denmark produces a particular kind of learning subject with dual tracks for development, and we ask what kind of actions the students apply in order to stay becoming along both tracks. We apply theoretical conceptions of 'becoming' inspired by Brembeck and Johansson that allow us to understand how the sports students live up to the code of conduct of the sports classes. The article is based on an ethnographic study carried out in four schools located in four regions of Denmark. We argue that the hybrid obliges students to follow a narrow developmental track with an ambitious goal of performing in both sport and school, and that the hybrid is threatened when a sports student prioritises either sport or school while he/she is still enrolled in the class.