In the United States, culturally responsive computing is a framework that aims to support broadening the participation of racially and linguistically diverse children in computing and technology education through bottom-up interventions that are community-oriented, technology rich, and culturally dynamic. Despite the important role that youth sports play in many local neighborhoods and communities across demographic groups there is only a small amount of research on developing culturally responsive computing education that incorporates these activities. We report findings from a culturally responsive computing collaboration between computing education researchers and coaches, mentors, and academic staff who ran a youth boxing program that predominantly served African American children. The purpose of the collaboration was to learn about and represent the adults' expertise and knowledge in the co-development of culturally responsive computing activities. Using an emergent mixed methods research design, we collected qualitative data (i.e., interviews and group discussions) and quantitative data (i.e., pre- and post-surveys) throughout the collaboration. We analyzed these data to study how coaches, mentors, and staff members brought their knowledge and expertise to bear on the co-development of culturally responsive computing activities for the youth boxing program. Our findings show how the coaches, mentors, and academic staff used their expertise and knowledge in ways that leveraged boxing culture to go beyond boxing itself in the co-development of the activities. In addition, even when connections between computing and boxing did not appear authentically motivated this did not negate the adults' engagement with the culturally responsive computing project. These findings have implications for anti-deficit theorizing about authenticity and inauthenticity in the co-development of culturally responsive computing in youth sports contexts. The construction of authenticity in culturally responsive computing might be less understood as a direct translation from community into education and more so as a negotiation between locally defined demarcations of what is considered authentic and inauthentic.