Gendered differences in participation in active lifestyles (encompassing sport, physical activity, and physical education) are well established, with young men typically participating in more activities than young women. This paper uses a theoretical approach inspired by Bourdieu's notions of habitus, field and capital to explore the 'how' and 'why' of these differences. Drawing on mixed-methods data obtained from questionnaires (n = 332) and semi-structured interviews with 33 young men and 37 young women aged 15-16, we present two gendered trends which explain gendered differences in active lifestyle participation. Firstly, in this research, young men participated in more activities than young women, viewing their participation as integral to their identity, their sense of self. Young women, in contrast, viewed sport as an 'optional' extra, something they could do, if they wished. Secondly, in relation to the differences in the type of activities participated in, young men were more likely to participate in traditional team sports, whereas young women chose to engage in gym/fitness activities to promote appearance and feminine attractiveness. We argue that the gendered norms which dictate 'appropriate' gendered active identities are damaging to both young men and women who may wish to deviate from these norms. Social capital is allocated to gendered bodies in accordance with these norms, influencing how young people are viewed in their social hierarchies. A gender-neutral narrative which destabilises gendered sporting norms whilst simultaneously celebrating diversity is needed to promote a safe and inclusive environment where all young men and women can engage in sufficient physical activity.